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Micro tensile bonding strength to milled and printed permanent CAD/CAM materials
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Micro tensile bonding strength to milled and printed permanent CAD/CAM materials
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Content
Copyright 2023 Waad Mzain
Micro Tensile Bonding Strength to Milled and Printed Permanent
CAD/CAM Materials
By
Waad Mzain, BDS
A Thesis Presented to the
FACULTY OF THE USC HERMAN OSTROW SCHOOL OF DENTISTRY
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
MASTER OF SCIENCE
(BIOMATERIALS AND DIGITAL DENTISTRY)
December 2023
ii
Dedication
To my parents, Mohammed Mzain and Safyah Kalanta, and my siblings Hamzah, Abdulaziz,
Muyaser, Feras, Mayar, Narmeneen, and Lara, I want to express my profound gratitude for the
consistent love, support, and motivation you've provided me with throughout my academic
journey. Your unwavering belief in my abilities has been my source of strength and
determination. I dedicate this thesis to you in recognition of the sacrifices you've made, the latenight discussions we've had, and your enduring faith in my aspirations. Your love forms the
bedrock upon which my achievements are built, and I will forever cherish your presence in my
life.
With all my love,
iii
Acknowledgments
I want to express my gratitude and appreciation to Allah, the Almighty, whose gracious help
made it possible for me to complete this work. I also extend my heartfelt thanks to my home
country, the Kingdom of Saudi Arabia, and Saudi Ministry of Education for financial support. I
am profoundly appreciative of this support.
First and foremost, I would like to convey my deep appreciation to my advisor, Dr. Jin-Ho
Phark. His expertise, understanding, time, and patience were invaluable additions to my graduate
journey. I am truly grateful for his unwavering support, advice, guidance, and mentorship
throughout my master's program.
I would also like to extend special thanks to my co-supervisor, Dr. Sillas Duarte, for his
professionalism, expertise, understanding, patience, and mentorship during my clinical training
in digital and adhesive restorative dentistry. His guidance played a significant role in my
achievements during the program.
I must express my gratitude to my other thesis advisory committee member, Dr. Nazanin
Forghani, for taking the time to review my thesis. I am delighted to collaborate with you and
eagerly anticipate learning more from your expertise.
A big thank you goes out to my faculty members during my Advanced Operative and Adhesive
Dentistry program, namely Dr. Alena Knezevic, Dr. Eddie Sheh, and Dr. Jenny Son. I am
thankful for your continuous support, guidance, and encouragement during my training.
I would also like to acknowledge the exceptional efforts of Ms. Karen Guillen, the program
specialist, for going above and beyond to accommodate my requests.
I would like to express my gratitude to my fellow resident colleagues, Jordi, Flavio, and
Alejandra, for their consistent motivation and words of support as we navigate this shared
journey. Additionally, I want to extend my appreciation to my friends during this journey,
namely Dr. Sarah Alsaleh, Bayan Badeeb, Nora Bahibishi, Manar Al Abdelkarim, and Kholoud
Alzaharani, for their unwavering support and assistance.
iv
Table of Contents
Dedication ......................................................................................................................................ii
Acknowledgments.........................................................................................................................iii
List of Tables............................................................................................................................... viii
List of Figures ............................................................................................................................. xiv
Abstract ..................................................................................................................................... xviii
Chapter One: Introduction..............................................................................................................1
1. Composite Composition: ....................................................................................................1
1.1. Organic Components: .................................................................................................1
1.2. Inorganic Components:...............................................................................................2
1.3. Coupling Agents: ........................................................................................................2
1.4. Initiator: ......................................................................................................................3
2. Degree of Conversion (DC):...............................................................................................5
3. CAD/CAM Materials: ........................................................................................................5
3.1. Subtractively Manufactured CAD/CAM Materials: ...................................................6
3.2. Additively Manufactured/Printed CAD/CAM Materials:...........................................8
4. Bonding Mechanism:........................................................................................................10
4.1. Micromechanical Retention:.....................................................................................10
4.2. Mechanical Treatment: .............................................................................................11
4.3. Chemical Surface Treatment:....................................................................................12
5. Adhesive Systems:............................................................................................................13
5.1. Total Etch Systems (Etch-and-Rinse Adhesives):.....................................................13
5.2. Self-etch Systems (Etch-and-Dry Adhesives):..........................................................14
6. Resin Cement: ..................................................................................................................17
v
6.1. Adhesive-Based Resin Cement:................................................................................17
6.2. Self-Adhesive Resin Cements: .................................................................................19
7. Bonding Testing:...............................................................................................................20
7.1. Micro Tensile Test: ...................................................................................................21
7.2. Micro Shear Test:......................................................................................................22
7.3. Retention Testing:.....................................................................................................23
8. Objective: .........................................................................................................................26
9. Aim:..................................................................................................................................26
10. Null Hypothesis:...............................................................................................................26
Chapter Two: Materials and Method ............................................................................................27
2. Specimen Fabrication and Preparation .............................................................................31
2.1. Object Fabrication ....................................................................................................31
2.2. Polishing:..................................................................................................................34
2.3. Treatment of the Bonding Surface:...........................................................................35
2.4. Bonding Procedure: ..................................................................................................40
2.5. Specimen/Stick Fabrication:.....................................................................................42
3. Artificial Aging.................................................................................................................43
3.1. Thermal Fatigue:.......................................................................................................43
4. Micro Tensile Bond Strength (μTBS) Testing: .................................................................44
5. Failure mode analysis.......................................................................................................44
6. Statistical Analysis: ..........................................................................................................46
6.1. Micro Tensile Bond Strength:...................................................................................46
6.2. Weibull Analysis:......................................................................................................47
Chapter Three: Results .................................................................................................................49
1. Descriptive Analysis of Micro Tensile Bond Strength (µTBS): .......................................49
vi
2. Data Normality Analysis and Equality of Variances:........................................................52
3. Analysis of Variance (ANOVA): ......................................................................................54
3.1. Materials:..................................................................................................................55
3.2. Surface Treatment: ...................................................................................................88
3.3. Ar=ficial Aging:........................................................................................................123
4. Analysis of Failure Mode:................................................................................................128
4.1. Overall:....................................................................................................................128
4.2. Rela=on of Failure Mode and Material:..................................................................129
4.3. Rela=on of Failure Mode and Surface Treatment:..................................................130
4.4. Rela=on of Failure Mode and Aging: ......................................................................132
5. Weibull Analysis:.............................................................................................................133
5.1. Materials:................................................................................................................137
5.2. Surface Treatment: .................................................................................................153
Chapter Four: Discussion ...........................................................................................................182
1. Materials:........................................................................................................................182
1.1. Factors Affecting the mechanical Properties of 3D Printed Materials:...........................183
1.1.1. Degree of Conversion and Post-Curing Procedures: ..............................................183
1.1.2. Layer Thickness:.....................................................................................................184
1.1.3. Printing Angulation: ...............................................................................................185
1.1.4. Printers:...................................................................................................................185
2. Surface Treatment:..........................................................................................................186
2.1. Control....................................................................................................................186
2.2. Airborne Particle Abrasion .....................................................................................186
2.3. Coupling Agents: ....................................................................................................187
2.4. Adhesive:................................................................................................................188
4. Aging:.............................................................................................................................189
5. Testing: ...........................................................................................................................191
vii
6. Violation of ANOVA prerequisites: ................................................................................192
7. Weibull Statistics for Bond Strength Data:.....................................................................193
Conclusions................................................................................................................................195
References..................................................................................................................................196
viii
List of Tables
Table 1: Material Composition __________________________________________________ 28
Table 2: Overall Micro Tensile Bond Strength (MPa) of Lava Ultimate, VarseoSmile Crown Plus,
and Ceramic Crown ______________________________________________________ 51
Table 3: Shapiro-Wilk Test (Normality) ___________________________________________ 52
Table 4: Levene’s Test (Equality of Variances)______________________________________ 53
Table 5: Summary of Analysis of Variance (Material, Surface Treatment, and Aging) and Their
Interactions _____________________________________________________________ 54
Table 6: Estimated Marginal Means (Material) _____________________________________ 55
Table 7: Group-wise Comparisons (Material) ______________________________________ 55
Table 8: Analysis of Variance of Control Non-Aged Surface Treatment (Materials)_________ 56
Table 9: Estimated Marginal Means (Material) in control Non-Aged ____________________ 56
Table 10: Group-Wise Comparisons (Material) in Control Non-Aged ___________________ 57
Table 11: Analysis of Variance of Control Aged Surface Treatment (Materials) ____________ 58
Table 12: Estimated Marginal Means (Material)in control Aged ________________________ 58
Table 13: Group-Wise Comparisons (Material) in Control Aged________________________ 59
Table 14: Analysis of Variance of Airborne Particle Abrasion Non-aged Surface Treatment
(Materials)______________________________________________________________ 60
Table 15: Estimated Marginal Means (Material)in Airborne Particle Abrasion Non-Aged ____ 60
Table 16: Group-wise Comparisons (Material)in Airborne Particle Abrasion Non- Aged_____ 61
Table 17: Analysis of Variance of Airborne Particle Abrasion Aged Surface Treatment (Materials)
_______________________________________________________________________ 62
Table 18: Estimated Marginal Means (Material) in Airborne Particle Abrasion Aged________ 62
Table 19: Group-wise Comparisons (Material) in Airborne Particle Abrasion Aged_________ 63
Table 20: Analysis of Variance of Silane Non- Aged Surface Treatment (Materials) ________ 64
Table 21: Estimated Marginal Means (Material) in Silane Non- Aged ___________________ 64
Table 22: Group-wise Comparisons (Material) in Silane Non-Aged _____________________ 65
Table 23: Analysis of Variance of Silane Aged Surface Treatment (Materials) _____________ 66
Table 24: Estimated Marginal Means (Material)in Silane Aged_________________________ 66
Table 25:Group-wise Comparisons (Material) in Silane Aged__________________________ 67
ix
Table 26: Analysis of Variance of Adhesive Non-Aged Surface Treatment (Materials) ______ 68
Table 27: Estimated Marginal Means (Material) in Adhesive Non- Aged _________________ 68
Table 28: Group-wise Comparisons (Material) in Adhesive Non- Aged __________________ 69
Table 29: Analysis of Variance of Adhesive Aged Surface Treatment (Materials)___________ 70
Table 30: Estimated Marginal Means (Material) in Adhesive Aged______________________ 70
Table 31: Group-wise Comparisons (Material) in Adhesive Aged_______________________ 71
Table 32: Analysis of Variance of Airborne Particle Abrasion+ Silane Non- Aged Surface
Treatment (Materials) _____________________________________________________ 72
Table 33: Estimated Marginal Means (Material) in of Airborne Particle Abrasion+Silane NonAged __________________________________________________________________ 72
Table 34: Group-wise Comparisons (Material)in Airborne Particle Abrasion+Silane Non- Aged
_______________________________________________________________________ 73
Table 35: Analysis of Variance of Airborne Particle Abrasion+Silane Aged Surface Treatment
(Materials)______________________________________________________________ 74
Table 36: Estimated Marginal Means (Material)in of Airborne Particle Abrasion+Silane Aged 74
Table 37: Group-wise Comparisons (Material)in Airborne Particle Abrasion+Silane Aged ___ 75
Table 38: Analysis of Variance of Silane + Adhesive Non-Aged Surface Treatment (Materials) 76
Table 39:Estimated Marginal Means (Material) in of Silane + Adhesive Non- Aged ________ 76
Table 40: Group-wise Comparisons (Material) in Silane + Adhesive Non- Aged ___________ 77
Table 41: Analysis of Variance of Silane + Adhesive Aged Surface Treatment (Materials) ___ 78
Table 42: Estimated Marginal Means (Material) in of Silane + Adhesive Aged ____________ 78
Table 43: Group-wise Comparisons (Material) in Silane + Adhesive Aged________________ 79
Table 44: Analysis of Variance of Airborne Particle Abrasion +Adhesive Non-Aged Surface
Treatment (Materials) _____________________________________________________ 80
Table 45: Estimated Marginal Means (Material) in of Airborne Particle Abrasion +Adhesive
Non-Aged ______________________________________________________________ 80
Table 46: Group-wise Comparisons (Material) in Airborne Particle Abrasion +Adhesive NonAged __________________________________________________________________ 81
Table 47: Analysis of Variance of Airborne Particle Abrasion +Adhesive Aged Surface Treatment
(Materials)______________________________________________________________ 82
x
Table 48: Estimated Marginal Means (Material) in of Airborne Particle Abrasion +Adhesive
Aged __________________________________________________________________ 82
Table 49: Group-wise Comparisons (Material) in Airborne Particle Abrasion +Adhesive Aged 83
Table 50: Analysis of Variance of Airborne Particle Abrasion +Silane +Adhesive Non-Aged
Surface Treatment (Materials) ______________________________________________ 84
Table 51: Estimated Marginal Means (Material) in of Airborne Particle Abrasion +Silane
+Adhesive Non-Aged _____________________________________________________ 84
Table 52: Group-wise Comparisons (Material) in Airborne Particle Abrasion +Silane +Adhesive
Non-Aged ______________________________________________________________ 85
Table 53: Analysis of Variance of Airborne Particle Abrasion +Silane +AdhesiveAged Surface
Treatment (Materials) _____________________________________________________ 86
Table 54: Estimated Marginal Means (Material) in of Airborne Particle Abrasion +Silane
+Adhesive Aged _________________________________________________________ 86
Table 55: Group-wise Comparisons (Material) in Airborne Particle Abrasion Abrasion +Silane
+Adhesive Aged _________________________________________________________ 87
Table 56: Estimated Marginal Means (Surface treatment) _____________________________ 88
Table 57: Group-wise Comparisons (Surface Treatments)_____________________________ 89
Table 58: Mean Micro Tensile Bond Strength and Standard Deviation of Lava Ultimate_____ 91
Table 59: Analysis of Variance of Lava Ultimate (Surface Treatment, and Aging) and their
interactions _____________________________________________________________ 92
Table 60: Estimated Marginal Means (Surface Treatment) Lava Ultimate ________________ 92
Table 61: Group-wise Comparisons (Surface Treatment) in Lava Ultimate _______________ 93
Table 62: Analysis of Variance of Non-Aged Lava Ultimate (Surface Treatment) and its
Interactions _____________________________________________________________ 95
Table 63: Estimated Marginal Means (Surface Treatment) Non-Aged Lava Ultimate _______ 95
Table 64: Group-wise Comparisons (Surface Treatment) in Non-Aged Lava Ultimate ______ 96
Table 65: Analysis of Variance of Aged Lava Ultimate (Surface Treatment) and its Interactions 98
Table 66: Estimated Marginal Means (Surface Treatment) Aged Lava Ultimate____________ 98
Table 67: Group-wise Comparisons (Surface Treatment) in Aged Lava Ultimate___________ 99
Table 68: Mean Micro Tensile Bond Strength and Standard Deviation of VarseoSmile Crown
Plus __________________________________________________________________ 101
xi
Table 69: Analysis of Variance of VarseoSmile Crown Plus (Surface Treatment, and aging) and
their interactions ________________________________________________________ 102
Table 70: Estimated Marginal Means (Surface Treatment) VarseoSmile Crown Plus _______ 103
Table 71:Group-wise Comparisons (Surface Treatment) in VarseoSmile Crown Plus ______ 103
Table 72: Analysis Of Variance Of VarseoSmile Crown Plus Non-Aged (Surface Treatment) and
Its Interactions__________________________________________________________ 106
Table 73: Estimated Marginal Means (Surface Treatment) VareoSmile Crown Plus Non-Aged106
Table 74: Group-wise Comparisons (Surface Treatment) in VarseoSmile Crown Plus Non-Aged
______________________________________________________________________ 108
Table 75: Analysis of Variance of VarseoSmile Crown Plus Aged (Surface Treatment) and its
Interactions ____________________________________________________________ 109
Table 76: Estimated Marginal Means (Surface Treatment) VarseoSmile Crown Plus Aged __ 109
Table 77: Group-wise Comparisons (Surface Treatment) in VarseoSmile Crown Plus Aged _ 110
Table 78: Mean Micro Tensile Bond Strength and Standard Deviation of Ceramic crown ___ 112
Table 79: Analysis of Variance of Ceramic Crown (Surface Treatment, and Aging) and Their
Interactions ____________________________________________________________ 113
Table 80: Estimated Marginal Means (Surface Treatment) Ceramic Crown ______________ 114
Table 81: Group-wise Comparisons (Surface Treatment) in Ceramic Crown _____________ 114
Table 82: Analysis of Variance of Ceramic Crown Non- Aged (Surface Treatment) and its
Interactions ____________________________________________________________ 116
Table 83: Estimated Marginal Means (Surface Treatment) Ceramic Crown Non- Aged _____ 117
Table 84 :Group-wise Comparisons (Surface Treatment) in Non-Aged Ceramic Crown ____ 118
Table 85: Analysis of Variance of Ceramic Crown Aged (Surface Treatment) and its Interactions.
______________________________________________________________________ 119
Table 86: Estimated Marginal Means (Surface Treatment) Ceramic Crown Aged _________ 120
Table 87: Group-wise Comparisons (Surface Treatment) in Aged Ceramic Crown ________ 121
Table 88: Estimated Marginal Means (Aging) _____________________________________ 123
Table 89: Group-wise Comparisons (Aging) ______________________________________ 123
Table 90: Estimated Marginal Means of Lava Ultimate (Aging) _______________________ 125
Table 91: Group-wise Comparisons Lava Ultimate (Aging) __________________________ 125
Table 92: Estimated Marginal Means of VarseoSmile Crown Plus (Aging) ______________ 126
xii
Table 93:Group-wise Comparisons VarseoSmile Crown Plus (Aging) __________________ 126
Table 94: Estimated Marginal Means of Ceramic Crown (Aging)______________________ 127
Table 95: Group-wise Comparisons Ceramic Crown (Aging) _________________________ 127
Table 96: Failures mode distribution ____________________________________________ 128
Table 97: Percentage of type of failure and materials. _______________________________ 129
Table 98: Percentage of Failure Mode in Surface Treatment __________________________ 130
Table 99: Percentage of Failure Mode Based on Aging ______________________________ 132
Table 100: Weibull distribution (Two-parameters) Characteristic Strength (��) and Weibull
Modulus (m) of Lava Ultimate , VarseoSmile Crown Plus, and Ceramic Crown ______ 134
Table 101: Weibull Distribution (Two-Parameter) Characteristic Strength (σo) and Weibull
Modulus (m) of Lava Ultimate _____________________________________________ 137
Table 102: Weibull Distribution (Two-Parameter) Characteristic Strength (σo) and Weibull
Modulus (m) of VarseoSmile Crown Plus ____________________________________ 143
Table 103: Weibull Distribution (Two-Parameter) Characteristic Strength (σo) and Weibull
Modulus (m) of Ceramic crown ____________________________________________ 148
Table 104: Weibull distribution ( Two Parameters) Characteristic Strength ( ��) and Weibull
Modulus (m) of Control Treatment__________________________________________ 153
Table 105: Weibull Distribution (Two Parameters) Characteristic Strength (��) and Weibull
Modulus (m) of Airborne Particle Abrasion treatment ___________________________ 156
Table 106: Weibull Distribution (Two Parameters) Characteristic Strength (��) and Weibull
Modulus (m) of Silane Treatment___________________________________________ 159
Table 107: Weibull Distribution (Two Parameters) Characteristic Strength (�o) and Weibull
Modulus (m) of Adhesive treatment _________________________________________ 162
Table 108: Weibull Distribution (Two Parameters) Characteristic Strength (�o) and Weibull
Modulus (m) of Airborne Particle Abrasion+ Silane Treatment____________________ 164
Table 109: Weibull Distribution (Two Parameters) Characteristic Strength (�o) and Weibull
Modulus (m) of Silane+ Adhesive Treatment__________________________________ 168
Table 110: Weibull Distribution (Two Parameters) Characteristic Strength (�o) and Weibull
Modulus (m) of Airborne Particle Abrasion+ Adhesive treatment __________________ 171
Table 111: Weibull Distribution (Two Parameters) Characteristic Strength (�o) and Weibull
Modulus (m) of Airborne Particle Abrasion+ Silane+ Adhesive treatment ___________ 174
xiii
Table 112: Result Summary of the Group-wise Comparison (µTBS) and the Weibull Distribution
(Two-Parameters) Based on the Materials.____________________________________ 177
Table 113:Results Summary of the Group-wise Comparisons (µTBS) and Weibull Distribution
(Two-parameters) Based on Surface Treatments. _______________________________ 181
xiv
List of Figures
Figure 1: Classifica=on of indirect tooth-colored restora=ve materials_____________________6
Figure 2: Different Types of 3D Printed Materials and Their Printer. ______________________9
Figure 3: Bonding Tes=ng Method Including Tensile, Shear, Pull-away ____________________21
Figure 4: The Process of Testing the Micro Tensile Bond Strength. ______________________27
Figure 5: Resin Base CAD/CAM Materials: (A) Lava Ul=mate,(B) VarseoSmile Crown Plus ,and (C)
Ceramic Crown ___________________________________________________________28
Figure 6: Study Design _________________________________________________________30
Figure 7: Lava Ultimate Block Section Into 3 Cuboid by Precision Low-Speed Diamond Saw. 31
Figure 8: Cuboid Object Design Using Meshmixer (A) 14 × 14 × 6 mm ,(B) 14 × 14 × 5 mm ___32
Figure 9: VarseoSmile Crown Plus Specimen Prepara=on ______________________________33
Figure 10: Ceramic Crown Specimen Prepara=on ____________________________________34
Figure 11: Polishing Papers and The Bonding Surface A]er Polishing _____________________35
Figure 12: Airborne Par=cle Abrasion Treatment_____________________________________36
Figure 13: Silane Surface Treatment_______________________________________________36
Figure 14: Adhesive Surface Treatment ____________________________________________37
Figure 15: Airborne Par=cle Abrasion + Silane Surface Treatment _______________________38
Figure 16: Silane + Adhesive surface treatment______________________________________38
Figure 17: Air-Borne Par=cle Abrasion + Adhesive Surface Treatment ____________________39
Figure 18: Air-Borne Par=cle Abrasion + Silane + Adhesive Surface Treatment Steps. ________40
Figure 19: Bonding Steps _______________________________________________________42
Figure 20: (A) Bilayered object glued to the cylinder by Zap it, (B) Cylinder attached to the
circular holder, (C) Mount the holder to the machine, (D) Cut the sample slices, (E)Rotate
the bilayered sample 90° and cut into sticks. ___________________________________43
Figure 21: Thermo-Mechanical Cycles in Separate Mesh Pouch for Each Surface Treatments in
Each Materials. ___________________________________________________________43
Figure 22: µTBS Testing Steps___________________________________________________44
xv
Figure 23: (a) Adhesive (interface resin -adhesive), (b) Cohesive in Material, (c) Cohesive in
Cement, (d) Mixed Adhesive -Resin __________________________________________45
Figure 24: Overall Mean µTBS Values (MPa) ________________________________________49
Figure 25: Mean µTBS of Materials _______________________________________________55
Figure 26: Mean µTBS of Materials in Control Non-Aged _____________________________57
Figure 27: Mean µTBS of Materials in Control Aged _________________________________59
Figure 28: Mean µTBS of materials in Airborne Particle Abrasion Non- Aged _____________61
Figure 29: Mean µTBS of materials in Airborne Particle Abrasion Aged __________________63
Figure 30: Mean µTBS of Materials in Silane Non-Aged ______________________________65
Figure 31: Mean µTBS of Materials in Silane Aged __________________________________67
Figure 32: Mean µMTS of Materials in Adhesive Non- Aged___________________________69
Figure 33: Mean µTBS Of Materials in Adhesive Aged _______________________________71
Figure 34: Mean µTBS of Materials n Airborne Particle Abrasion+Silane Non- Aged _______73
Figure 35: Mean µTBS of materials in Airborne Particle Abrasion+Silane Aged____________75
Figure 36: Mean µTBS of Materials in Silane + Adhesive Non- Aged ____________________77
Figure 37: Mean µTBS of Materials in Silane + Adhesive Aged_________________________79
Figure 38: Mean µTBS of Materials Airborne Particle Abrasion +Adhesive Non-Aged ______81
Figure 39: Mean µTBS of materials Airborne Particle Abrasion +Adhesive Aged___________83
Figure 40: Mean µTBS of materials Airborne Particle Abrasion +Silane +Adhesive Non-Aged 85
Figure 41: Mean µTBS of materials Airborne Particle Abrasion +Silane +Adhesive Aged ____87
Figure 42: Mean µTBS for Different Surface Treatment _______________________________90
Figure 43: Micro Tensile Bond Strength of Lava Ultimate _____________________________91
Figure 44: Mean µTBS of different Surface Treatment (Lava Ultimate)___________________94
Figure 45: Mean µTBS of Different Surface Treatment (Non-Aged Lava Ultimate )_________97
Figure 46:Mean µTBS of different Surface Treatment (Aged Lava Ultimate) _____________100
Figure 47: Micro Tensile Bond Strength of VarseoSmile Crown Plus____________________102
Figure 48: Mean µTBS of Different Surface Treatments (VarseoSmile Crown Plus) ________105
Figure 49: Mean µTBS of Different Surface Treatments (VarseoSmile Crown Plus Non-Aged)
______________________________________________________________________107
xvi
Figure 50: Mean µTBS of Different Surface Treatments (VarseoSmile Crown Plus Aged) ___111
Figure 51: Micro Tensile Bond Strength of Ceramic Crown ___________________________112
Figure 52: Mean µTBS of Different Surface Treatments (Ceramic Crown) _______________116
Figure 53: Mean µTBS of Different Surface Treatments (Ceramic Crown Non-Aged) ______119
Figure 54: Mean µTBS of Different Surface Treatments (Ceramic Crown Aged) __________122
Figure 55: Mean µTBS of different material before and after aging _____________________124
Figure 56: Mean µTBS of Lava Ultimate before and after aging ______________________125
Figure 57: Mean µTBS of VarseoSmile Crown Plus before and after aging _______________126
Figure 58: Mean µTBS of Ceramic Crown before and after aging ______________________127
Figure 59: Percent of different failure modes_______________________________________128
Figure 60: Percentage of failure modes in different materials __________________________129
Figure 61: Percentage of failure modes with Different Surface Treatments _Error! Bookmark not
defined.
Figure 62: Bar Graph in Percentage of Failure Modes Based on Aging __________________132
Figure 63: Weibull Plot (Plots of Failure Probabilities Against Micro Tensile Bond Strength) of
Non-Aged Lava Ultimate __________________________________________________139
Figure 64: Weibull Plot (Plots of Failure Probabilities Against Micro Tensile Bond Strength) of
Aged Lava Ultimate ______________________________________________________140
Figure 65: Likehood Contour Plot of Lava Ultimate Non-Aged ________________________141
Figure 66: Likelihood Contour Plot of Lava Ultimate Aged ___________________________142
Figure 67: Weibull Plot (Plots of Failure Probabilities Against Micro Tensile Bond Strength) of
Non-Aged VarseoSmile Crown Plus _________________________________________145
Figure 68: Weibull Plot (Plots of Failure Probabilities Against Micro Tensile Bond Strength) of
Aged VarseoSmile Crown Plus______________________________________________146
Figure 69: Likelihood Contour Plot of VarseoSmile Crown Plus Non-Aged ______________146
Figure 70: Likelihood Contour Plot of VarseoSmile Crown Plus Aged___________________147
Figure 71: Weibull Plot (Plots of Failure Probabilities Against Micro Tensile Bond Strength) of
Non-Aged Ceramic Crown_________________________________________________150
xvii
Figure 72: Weibull Plot (Plots of Failure Probabilities Against Micro Tensile Bond Strength) of
Aged Ceramic Crown _____________________________________________________151
Figure 73: Likelihood Contour Plot of Ceramic Crown Non-Aged______________________152
Figure 74: Likelihood Contour Plot of Ceramic Crown Aged __________________________152
Figure 75: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Control __154
Figure 76: Likelihood Contour Plot (Control) ______________________________________155
Figure 77: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Airborne
Particle Abrasion_________________________________________________________157
Figure 78: Likelihood Contour Plot (Airborne Particle Abrasion)_______________________158
Figure 79: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Silane ___160
Figure 80: Likelihood Contour Plot (Silane) _______________________________________161
Figure 81: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Adhesive _163
Figure 82: Likelihood Contour Plot (Adhesive)_____________________________________164
Figure 83: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Airborne
Particle Abrasion+ Silane __________________________________________________166
Figure 84: Likelihood Contour Plot (Airborne Particle Abrasion+Silane) ________________167
Figure 85: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Silane+
Adhesive _______________________________________________________________169
Figure 86: Likelihood Contour Plot (Silane+ Adhesive) ______________________________170
Figure 87: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Airborne
Particle Abrasion + Adhesive _______________________________________________172
Figure 88: Likelihood Contour Plot (Airborne Particles Abrasion +Adhesive)_____________173
Figure 89: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Airborne
Particle Abrasion +Silane + Adhesive ________________________________________175
Figure 90: Likelihood Contour Plot (Airborne Particles Abrasion + Silane+ Adhesive) _____176
xviii
Abstract
Purpose: To evaluate influence of different surface treatments and artificial aging on the micro
tensile bond strength (µTBS) of three milled and printed permanent CAD/CAM materials (Lava
Ultimate [LU], VarseoSmile Crown Plus [VS], and Ceramic Crown [CC]).
Material and methods: Blocks of CAD/CAM materials (n=8/material; 14x14x6 mm;
n=8/material; 14x14x5 mm) were fabricated by cutting from CAD/CAM blocks or by printing.
After polishing of the bonding surface, specimens were divided into eight groups according to
the surface treatment: control (C), Airborne Particle Abrasion (P), Silane (S), Adhesive (A),
Airborne Particle Abrasion+ Silane (PS), Silane + Adhesive (SA), Airborne Particle Abrasion+
Adhesive (PA), and Airborne Particle Abrasion+ Silane +Adhesive (PSA). Blocks of 5- and 6-
mm thickness with the same surface treatment were bonded together using a dual-cure resin
cement (RelyX Ultimate). Every block was cut into 50 sticks with a dimension of 1.00 mm2
(±0.02). The sticks were subdivided into two subgroups: Non-Aged (.NA), and Aged (.A). µTBS
test was performed using a universal testing machine. Data were analyzed using 3-way and 2-
way ANOVA with Bonferroni post-hoc test (α=0.05). Weibull analysis was used to calculate the
Weibull Modulus and Characteristic Strength to create Weibull plots and likelihood contour
plots.
Results:
The micro tensile bond strength of the materials differed significantly from each other
(CC>LU>VS). A significant difference was found between the different surface treatments,
regardless of the Artificial Aging (PA>PS>PSA>P>S>SA>A>C). Aging significantly reduces
the µTBS of LU and CC but does not significantly affect the VS. The most frequent failure mode
was cohesive in resin, while for the milled material it was predominantly adhesive. Higher
Weibull modulus and characteristic strength values were observed with the milled material
compared to the printed materials.
xix
Conclusions:
Surface treatment significantly affects µTBS to milled and printed direct CAD/CAM resin
materials with increase of bond strength upon application of airborne particle. The adhesive
interface of the milled material (LU) has a lower probability of failure than the interface of the
printed materials (VS and CC).
1
Chapter One: Introduction
Nowadays, dental composite plays a vital role in dentistry. There are many applications,
including restorative materials, cavity liners, pit and fissure sealants, cores and buildups, inlays,
onlays, crowns, provisional restorations, cement for single or multiple tooth prostheses and
orthodontic devices, endodontic sealers, and root canal posts.
(1)
Resin-based dental materials were introduced in the 1950’s.
(1) Since then, many improvements
and changes have occurred in dental resins, such as composition, chemical formula, improving
the esthetics, mechanical and chemical properties. Dental composites were introduced to restore
anterior teeth. With the improvement of mechanical properties, they were used in the posterior
teeth.
(2) The Particle sizes and quantity affect the esthetic and mechanical properties of
composites.
1. Composite Composition:
Composites are composed of three main components: matrix (organic component), fillers
(inorganic component), coupling agent, and initiator.
(3)
1.1.Organic Components:
The resin matrix consists mostly of Bis-GMA (bisphenol-A- glycidyldimethacrylate). Since BisGMA is highly viscous alone, it is mixed in different combinations with short-chain monomers
such as TEGDMA (triethylenglycol-dimethacrylate). The lower the Bis-GMA content and the
higher the proportion of TEGDMA result in higher the polymerization shrinkage.
(4) Replacing
Bis-GMA with TEGDMA increases the tensile but reduces the flexural strength of the
material.
(5) Monomers can be released from the restorative material. Longer light polymerization
improves the rate of conversion (chain-linking of the individual monomers) and thus leads to less
monomer release.
(6)
2
1.2.Inorganic Components:
The fillers are made of quartz, ceramic, and/or silica. With increasing filler content, the
polymerization shrinkage, the linear expansion coefficient, and water absorption are reduced. On
the other hand, with increasing filler content, compressive and tensile strength, the modulus of
elasticity, and wear resistance are generally increased.
(7) The filler content of a composite is
sometimes determined by the shape of the filler. In a study with different types of composites,
those materials with pre-polymerized composite fillers were shown to have the lowest filler
content and thus also the lowest flexural strength and hardness. Composites with round fillers
had the highest filler content, which was associated with higher hardness and high flexural
strength. For mixed filler particles (hybrid composites) there was no linear relationship between
filler content and flexural strength.
(7)
Composite resins can be classified according to filler size into one of three groups: microfilled,
hybrid, or nanofilled. Microfilled composite resins have an average filler size of 40 to 1,200 nm
and relatively low filler content of 30% to 60% by volume, hybrid filler sizes ranging between
60 and 1,000 nm. Most hybrid composite resins present a filler ratio of 60% to 70% by volume.
Hybrid composite resins can be subclassified into three groups according to the filler size: Ihybrids: average particle size greater than 600 nm; II- micro-hybrids: particle size ranging from
10 to 3,000 nm and mean filler size ranging from 400 to 600 nm; and III- nanohybrids: filler size
ranging from 10 to 2,000 nm and average filler size ranging from 200 to 300 nm. Nanofilled:
nanoscale particles with a size of 100 nm and below and filler loading ranges from 55% to 70%
by volume.
(8)
1.3.Coupling Agents:
A coupling agent is applied to the surfaces of reinforcing particles (filler) to ensure that they are
chemically bonded to the resin matrix.
(9) Organo-silane compounds are the more common class
of dental composite coupling agents. It is essential that filler particles are bonded to the resin
matrix. This allows the more flexible polymer matrix to transfer stresses to the higher-modulus
(more rigid and stiffer) filler particles. The chemical bond between the two phases of the
composite is formed by a coupling agent; this is a difunctional surface-active compound that
3
adheres to filler particle surfaces and co-reacts with the monomer forming the resin matrix. A
properly applied coupling agent can impart improved physical and mechanical properties and
inhibit leaching by preventing water from penetrating along the filler-resin interface.(9)
Although titanates and zirconates can be used as coupling agents, organosilanes such as γmethacryloxypropyl tri- methoxysilane—are most common coupling agent. In the presence of
water, the methoxy groups (–OCH3) are hydrolyzed into silanol (–Si–OH) groups, which can
bond with other silanols on the filler surfaces by forming siloxane bonds (–Si–O–Si–). The
organosilane methacrylate groups form covalent bonds with the resin when it is polymerized,
thereby completing the coupling process. Proper coupling by means of organosilanes is
extremely important to the clinical performance of resin-based composite restorative materials.(9)
1.4.Initiator:
Initiator is a free radical-forming chemical, used to start the polymerization reaction. It enters the
chemical reaction and becomes part of the final polymer compound.(9) This free radical can be
produced by different method thermal, photochemical, and combined methods. (10) Thus, dental
composites can be light-cured, chemo-cured, or dual-cured.(11) The common dental composites
are light cured. It has an initiator system of photopolymerization and its amounts range from
0.1% to 1 wt%.(9) The amount of the initiator depends on the type of photosensitizer. The optimal
concentrations of initiators in resin-based composites depend on many factors such as the
solubility of these compounds in the monomer, photoreactivity, color or biocompatibility. (10)
The
process of polymerization has three phases: initiation, propagation, and termination. Free radicals
are necessary to lengthen the chain of polymer and they are formed by photoinitiators.(12)
Light Cure:
The free radicals are generated upon irradiation of blue light. After this, there is an exchange of
electrons in the initiator-co-initiator. Due to this process, free radicals are produced through
hydrogen abstraction. The initiator molecule becomes a ketyl radical while the co-initiator
molecule becomes an amino alkyl radical. The remaining electron of the alkene group reaches
the opposite terminal of the monomer and the whole molecule of the monomer becomes a
4
radical. This molecule reacts with another monomer, and it results in a chain reaction, which
ends when two radicals react with each other. In this reaction some of monomers do not
polymerize and they remain uncured. The relation between the uncured monomers and cured
resin is the degree of conversion (DC). (13)
There are two types of photoinitiators: type I includes
trimethylbenzoyl-diphenylphosphine oxide (TPO),(14) benzoyl peroxide (BPO), and type II
includes camphorquinone (CQ), phenanthrenequinone (PQ), benzophenone (BP)(15) and 1-
phenyl-1,2 propanodione (PPD) which combined two ways of polymerization.(13) The
photoinitiation system consists of photo-initiator and an electron donor or tertiary amine.(13) This
photoinitiator system is stable in the presence of the oligomer at room temperature, as long as the
composite is not exposed to light.(9)
Chemical Cure:
Chemical activation is a reaction between an organic amine catalyst paste and an organic
peroxide universal paste. After mixing these two pastes free radicals are produced. The free
radicals attack the carbon double bonds and the process of polymerization begins. This process
runs rapidly.(10) The chemical-curable resins have quite similar compositions like the light-cured
one but have different initiators of polymerization. The initiator is per-compound: benzoyl
peroxide, and it is combined with an aromatic tertiary amine.(12)
Dual Cure:
Some dental composites are dual cured. In these materials, the polymerization starts after
irradiation of light. They include photoinitiators like CQ and also iodonium salts and electron
donors, which generate the reactive cationic species that start the polymerization process.(16) The
aim of this dual cure mechanism is to achieve a higher degree of conversion, especially at areas
far away from the light source.(10)
5
2. Degree of Conversion (DC):
The DC measures how many carbon-carbon double bonds have been converted to single bonds
in a polymeric resin. The DC of a resin determines its strength, wear resistance, and many other
properties. Composites composed of bis-GMA, which are highly cross-linked, typically have a
conversion rate of 50% to 60%, which indicates that 50% to 60% of the methacrylate groups
have polymerized. This does not necessarily mean 40% to 50% of the monomer molecules are
left in the resin. Because the pendant group is still formed when one of the two methacrylate
groups per methacrylate molecule is covalently bonded to the polymer structure. (9)
Multiple factors determine whether a monomer converts to a polymer, including resin
composition, light transmission, sensitizer concentrations, initiator concentrations, and inhibitor
concentrations. The transmission of light through a material is determined by the intensity of the
lamp, absorption, scattering of light from filler particles, opacifiers, and any teeth interposed
between the lamp and the composite.(9)
In composites containing the same monomer formulations, the DC content does not differ when
chemically or light activated. For both curing systems, conversion values range from 50% to
70%. As with polymerization shrinkage, neither light nor chemically activated resins show
significant differences. Nonetheless, curing shrinkage can cause substantial stress buildup and
leakage at the resin margins in light-cured materials, which can result in staining, sensitivity, and
secondary caries. (9)
3. CAD/CAM Materials:
CAD/CAM technology refers to computer-aided design (CAD) and computer-aided
manufacturing (CAM). The CAD/CAM technology includes three main parts: data acquisition
device, designing program, and production technology. The production of CAD/CAM materials
can be done in two different ways: Subtractive manufacturing (milling) or additive
manufacturing (3D printing).
(17) Subtractive manufacturing is the milling of 3-dimensional dental
restorations from a block of material. In contrast, additive manufacturing, known as 3D printing
6
or rapid prototyping, fabricates objects directly from 3D models layer by layer until the object is
completed.
3.1.Subtractively Manufactured CAD/CAM Materials:
With CAD-CAM, high-performance materials can now be manufactured industrially and then
milled. In comparison with hand-built materials, CAD-CAM blocks are more homogeneous,
have fewer flaws and pores, and are more reliable.
(18) The indirect tooth-colored restorative
materials are classified into three main groups according to their composition: (I) glass matrix
ceramic, (II) polycrystalline ceramic, and (III) resin matrix ceramic.
(19) (Figure 1)
Figure 1: Classifica0on of indirect tooth-colored restora0ve materials
3.1.1. Glass Matrix Ceramic:
Nonmetallic inorganic ceramic materials that contain a glass phase are sub-divided into three
subgroups: naturally occurring feldspathic ceramics, synthetic ceramics, and glass-infiltrated
ceramics.(19)
3.1.2. Polycrystalline Ceramic:
Dental ceramic
Glass matrix ceramic
Natural
Feldspathic
Synthethic
Leucite- base
Lithium
disllicate
Fluorapatitebased
Glassinfiltrated
Alumina
Alumina and
magnesium
Alumina and
zirconia
Polycrystalline ceramic
Alumina
Stabilized zirconia
Zirconia- toughened
alumina
Alumina- toughened
zirconia
Resin matrix ceramic
Resin nano ceramic
Glass- ceramic in resin
interpenetrating matrix
Zirconia- silica ceramic in
resin interpenetrating
matrix
7
Nonmetallic inorganic ceramic materials that do not contain any glass phase and are divided into
four subgroups: alumina, stabilized zirconia, zirconia-toughened alumina, and aluminatoughened zirconia. (19)
3.1.3. Resin Matrix Ceramic:
Resin matrix ceramic or ceramic-reinforced polymer should have a high ceramic content of 80%
or higher with the remaining content being a cross-linked polymeric matrix, followed by
industrial polymerization that minimizes the amount of unreacted monomers. Ceramic-reinforced
polymer materials can be subcategorized, based on the method of embodiment of ceramic into
the polymer matrix: polymer-infiltrated ceramic (PIC) and resin nanoceramic (RNC).
(20)
Polymer-Infiltrated Ceramic (PIC) such as Vita Enamic (Vita Zahnfabrik, Bad Säckingen,
Germany) is a CAD/CAM block made of porous pre-sintered feldspar ceramic network matrix
infiltrated with organic polymer. This interpenetrating ceramic network material contains 86
wt% of geometrically interconnected porous feldspar and 14 wt% of conventional polymers,
such as urethane methacrylate (UDMA) and triethylene glycol dimethacrylate (TEGMA). A
ceramic powder is compressed into blocks and then sintered to a porous network. The resulting
presintered feldspar ceramic network has a three-dimensional interconnected geometry that
needs to be conditioned by a coupling agent to promote binding between the different phases of
the material. The chemically conditioned ceramic network is infiltrated with a cross-linking
polymer by capillary action and then polymerized under high heat (≈180oC) and high pressure
(≈300 MPa),(21, 22) forming a polymer-infiltrated ceramic network.
(21, 23) The density and
processing temperature have a significant influence on the final properties of this material.
(23) It
has been observed that higher density of the pre-infiltrated ceramic and higher infiltration
pressure provide superior mechanical properties.
(24) Optimal density is essential to provide
complete infiltration of the polymer.
Resin Nanoceramic (RNC) such as Lava Ultimate (3M ESPE, St Paul, MN, USA) is a
CAD/CAM block made with engineered zirconia/silica nanoparticles dispersed into a nanofillerreinforced polymer matrix. The inorganic phase (zirconia and silica nanoparticles) represents
approximately 80 wt% of the CAD/CAM material, the organic polymer phase about 20 wt%
8
(UDMA [urethane dimethacrylate] and Bis-EMA [bisphenol A polyethethylene glycol diether
dimethacrylate]). Engineered nanoparticles consist of silica, with a mean particle size of 20 nm
in diameter, and zirconia, with article size ranging from 4 to 11 nm in diameter. These
engineered nanoparticles are treated with coupling agents, which will bond chemically to the
filler surface and allow a chemical bond to the resin polymeric matrix.
Nanofillers are then distributed within the polymeric matrix as (I) dispersed, non-aggregated
individual particles (II) nanoclusters made of loosely bound aggregated silica/zirconia
nanoparticles. The addition of the nanofillers to the nanoclusters reduces the interstitial spacing
and increases the filler loading. Thus, the filled resin matrix shows improved resistance over that
of the polymer alone. The mixture is then heat processed for multiple hours in a proprietary
controlled heat treatment, resulting in a thorough cure and a high degree of cross-linking.
(20)
3.2.Additively Manufactured/Printed CAD/CAM Materials:
3.2.1. Manufacturing Technology:
3D printing is an additive manufacturing technology, that is divided into eight different
categories (Figure 2) by the American Section of the International Association for Testing
Materials (ASTM International). The eight categories are stereolithography (SLA), Poly jet (PJ),
electron beam melting (EBM), fused deposition modeling (FDM), binder jetting(BJ), selective
laser sintering (SLS), laminated object manufacturing (LOM), and highspeed sintering (HSS).
(25)
The liquid base materials are the most common materials used in dentistry, so stereolithography
(SLA) with Digital Light Processing (DLP) is probably the most popular additive manufacturing
system.
(26) The SLA technology was developed by Chuck W. Hull in 1986.
(27, 28) In the SLA
printer, the building platform is immersed in the resin liquid and an ultraviolet laser with 355 nm
wavelength polymerizes each layer. The liquid resin solidifies when scanned with a laser beam.
The advantage of this technology is that it is temperature resistant and can create complex
geometries within the limits of the support structures.
(29) There is primarily a difference in the
light source used in the two procedures. DLP uses short wavelength visible light (380 nm and
405 nm) instead of ultraviolet (UV) laser light in SLA.
(30) With DLP 3D printing, a single layer
can be printed and cured across the entire build plate in just a few seconds, whereas traditional
9
SLA requires several minutes. A third advantage of DLP is that it uses less material, which
lowers production costs.(26)
Figure 2: Different Types of 3D Printed Materials and Their Printer.
3.2.2. Printed Materials:
Multiple printable resins are available in dentistry for various applications. The 3D printed
materials companies manufactures different materials for different purposes, such as wax resin,
model resin, provisional resin, and permanent restoration resin. Dental Resin Permanent Crown
from different 3D printed materials is a new indirect resin ceramic fill material that can be
printed. The company specifications state that ceramic-filled resin can be used for single crowns,
inlays, onlays, and veneers. Using a 3D printer for permanent crowns can improve the patient's
treatment by providing a faster and more economical procedure with many applications.
(29) 3D
printers improve our profession in many aspects, such as efficiency with dental models, dentures,
diagnostic wax-ups, custom trays, surgical guides, and provisional and permanent crowns.
Photosensitive resin is used in photocuring 3D printing. Depending on the lamp wavelength and
printing technology, the photocuring mechanism would be chosen. The photosensitive resin used
in the SLA technique is typically cationic photopolymerized or hybrid photopolymerized.
(31) This
mechanism is chosen for three reasons. Firstly, SLA uses a laser beam with a wavelength of 355
nm, which is suitable for radical and cationic photopolymerization. Second, volume shrinkage is
the fatal weakness of photopolymerization, it induces internal stress that leads to material
deformation and eventually breaks it. As a result, the precision of the printing model declines
10
when volume shrinkage occurs. Scientists try to overcome volume shrinkage when printing 3D
objects using photo-curing.
(32) There is no or minimal volume shrinkage during cationic
photopolymerization.(33) Thus, cationic photosensitive resin is a good choice to photocured 3D
printing when the light source matches the absorption of cationic photo initiators. Thirdly, the
resins for cationic photopolymerization are rare and the initiator is expensive, but the induction
period for photopolymerization is long, so hybrid photosensitive resins are often used, which are
mixtures of radical and cationic photosensitive resins. In addition to adjusting the quality and
printing rate, hybrid resins could also adjust the price.
(31)
4. Bonding Mechanism:
The success of indirect restoration depends on its bonding strength to the underlying substrate.
(34, 35) The surface treatment of the intaglio surface of indirect composite resin restoration
influences bonding strength to the substrate. The surface treatment of different types of
restoration depends on the composition, and it could be classified as mechanical or chemical. (36,
37)
4.1.Micromechanical Retention:
Resin cements are characterized by low solubility and good adhesion to the tooth structure. (38, 39)
These cements act as the main link between the indirect esthetic restoration and the tooth
structure. To achieve good bonding to the resin cement, micromechanical means of retention
should be created on the intaglio surface of the indirect restorations.
(34, 37, 40, 41) Hydrofluoric acid
etching and grit-etching are well-known procedures for mechanical surface treatment.
(42)
Chemical Etching with Hydrofluoric Acid:
Hydrofluoric acid etching is a procedure that creates micro-roughness on the intaglio surface of
ceramic restorations and improves cement bond.
(42, 43) The chemical etching of feldspathic
ceramics with hydrofluoric acid results in a honeycomb-like topography of the ceramic surface,
which is ideal for micromechanical adhesion.
(43, 44) This surface topography results from the
11
chemical reaction between hydrofluoric acid and the silica phase of feldspathic ceramics,
forming a hexafluorosilicate salt that is easily removed by water rinsing.
(44-46)
A study on etching time's effect on the bonding procedures evaluating five different etching
times (5, 30, 60, 120, and 180 s) showed that resin cement did not bond to unetched ceramic. In
contrast, bonding was successfully achieved with the etched ceramic, and the 120 s etch resulted
in the highest bond strength.
(45) The bond strength of resin cements increases with increasing
ceramic surface roughness induced by acid etching.
(47)
Lithium disilicate ceramics have shown higher flexure resistance and bond strength values when
etched with 9.5% hydrofluoric acid instead of 4% acidulated phosphate fluoride.
(47) The etching
dental ceramics with 9.5% hydrofluoric acid for 20 s create an adhesion-favorable surface.
(37)
However, hydrofluoric acid etching results in shallow surface roughness that is unfavorable for
micromechanical interlocking in alumina-reinforced ceramic restorations like In-Ceram alumina
system, and zirconia-reinforced restorations like In-Ceram zirconia system (Vita Zahnfabrik,
Seefeld, Germany) due to their low silica content.
(34, 37, 48, 49) Sen et al. reported that hydrofluoric
acid etching was not enough to achieve strong bonding between resin cements and zirconia
ceramics compared to grit-etching which creates a micromechanical adhesion-favorable surface
and can be considered a good alternative to hydrofluoric acid etching.
(50) This study also defined
several important parameters to be followed to maximize the results of surface grit-etching such
as particle type, size, shape, incidence angle, and wet versus dry particles. (50)
4.2.Mechanical Treatment:
Air-borne Particle abrasion alone provides insufficient bond strengths for felspathic ceramics and
may induce chipping and loss of ceramic material and is therefore not recommended for
treatment of silica-based all-ceramic restorations.
(51-53) Comparing the Air-borne Particle
abrasion to different acid-etching agents on feldspathic porcelain and shows that hydrofluoric
acid and phosphoric acid provided the highest bond strengths. (44) Air-borne Particle abrasion
affects the bonding strength of different materials as well as the surface roughness. The
Aluminum Oxide Particle is the most used material in dental surface treatment with different
12
sizes and pressures. The most commonly used particle sizes are 50 µm and 110 µm, with
pressures of 1-2 and 3 bar. The best option for increasing the surface roughness which will
increase the bonding strength without damaging the surface by creating a micro crack is using
50µm with a 2 bar pressure.
(54, 55)
Lithium disilicate ceramics can achieve good bonding with resin cement when sandblasted or
acid-etched by hydrofluoric acid. It has been shown that lithium disilicate ceramics attained
similarly high bond strength values with aluminum oxide grit-etching for 10 s and also with
hydrofluoric acid etching for 20 s.
(42)
Etching indirect composite resin restorations with hydrofluoric acid results in microstructural
alteration of the composite due to the dissolution of the inorganic particles present in composite
resins, and thus the resin organic matrix becomes the dominant component of the surface which
makes the restoration-cement adhesive interface less resistant to debonding.
(36) However, gritetching indirect composite restorations with aluminum oxide particles is the best alternative to
increase the restoration surface energy.
(36, 56) Grit-etching promotes non-selective degradation of
the composite and results in better adhesion to the resin cement.
(36, 56-58)
4.3.Chemical Surface Treatment:
Coupling Agents:
Silane coupling can be used to enhance the bond between the indirect restoration and the resin
cement. Although it cannot substitute the mechanical surface treatment, it is used as an additional
step to strengthen the bonding by chemical means.
(42) A silane molecule has ethoxy groups to
bond to the inorganic particles of ceramics and an organofunctional group, typically a
methacrylate, to react with the organic matrix of composite resins forming covalent bonds.
(59, 60)
The chemical structure of the silane is R′— Si(OR)3, where R′ is the organofunctional group and
(OR) is the ethoxy group where R refers to the alkyl group. The ethoxy group is hydrolyzed to
result in a silanol (SiOH) that reacts with the silicon inorganic particles in the ceramic creating a
siloxane covalent bond (Si—O—Si).
(9, 61-63)
13
A silane-coupling agent is applied to the ceramic surface to chemically bond the inorganic phase
in the ceramic and the organic phase of the composite cement.
(59, 64) Bona et al. have
demonstrated that silane application improves the bonding to ceramics reinforced with feldspar,
leucite, or lithium disilicate, but cannot be a substitute for mechanical surface treatment.
(65)
Inorganic filler particles that exist on the surface of indirect composite resin allow the
development of chemical adhesion between these filler particles and the organic matrix of the
resin cement resulting in higher bond strength values.
(36) Soares et al. have reported that Airborne
Particle Abrasion of indirect composite resins together with the use of silane, results in high
bond strength values as opposed to Airborne Particle Abrasion without silane application.
(49) All
indirect composite resins present similar composition and their surface treatment tends to be the
same. (36)
The use of a primer containing 10-methacryloxydecyl dihydrogen phosphate (MDP) on zirconia
surfaces has been supported by numerous studies. According to the results, phosphate monomers
improve zirconia bonding.
(66, 67) According to the plausible mechanism, phosphate monomers
form chemical bonds with zirconia surfaces and have polymerizable resin terminal end groups
(e.g., methacrylate), which allow cohesive bonding with resin cement.
(68) Zirconia surface
bonding can also be achieved with a primer containing MDP, or a primer containing silane plus
phosphoric acid methacrylate and sulfide methacrylate components.
(69)
5. Adhesive Systems:
Throughout the last two decades, new adhesive systems have been introduced for bonding to
tooth structure. Adhesive materials can interact with tooth structure either mechanically,
chemically, or both. (70) The adhesive systems currently used for bonding to tooth tissue can be
summarized as following:
5.1.Total Etch Systems (Etch-and-Rinse Adhesives):
Total Etch is a multi-step approach that includes a separate etch-and-rinse phase. An acid
(usually 30-40% phosphoric acid) is applied for on dentin for 15 s and then rinsed off. This
14
demineralizes dentin up to a depth of a few micrometers resulting in the exposure of a
hydroxyapatite-deprived collagen mesh. Etching is followed either by priming then the
application of the adhesive resin (three-step procedure), or by applying a combined primer and
adhesive resin (two-step procedure).
(70, 71)
The total etch technique is the most effective approach to achieve bonding to enamel. Etching
results in dissolution of the hydroxyapatite crystals creating micro-porosities that are infiltrated
by fluid resin, which polymerizes and forms resin tags. Two types of resin tags are formed:
macro-tags that fill the space surrounding the enamel prisms, and micro-tags that fill the microporosities within the etched enamel prisms and contribute greatly to the retention in enamel.
(70, 72)
Etching dentin dissolves and removes the smear layer leaving a rinsed collagen layer, which,
when resin is applied, produces a resin–collagen hybrid layer, that is susceptible to degradation
upon water sorption and enzymatic degradation process.
(73-75)
Chemical bonding between resin and the organic component of dentin that remains after the acid
etch procedure contributes to a better bonding performance. However, this chemical bonding is
lacking due to hydrophilicity of the resins and hydrolytic reactions taking place at the adhesive
interface. Chemical bonding can be regarded as the major shortcoming of today‘s etch-and-rinse
adhesives.
(76, 77)
The priming step is very critical in the total etch approach. The highly technique sensitive wet
bonding technique should be used when using an acetone-based adhesive.
(78) The less techniquesensitive dry bonding technique, by applying a gentle stream of air-drying following the rinsing
step of the acid, should be employed when a water/ethanol-based adhesive is used.
(79, 80)
5.2.Self-etch Systems (Etch-and-Dry Adhesives):
These adhesives use monomers that are grafted with one or more carboxylic or phosphate acid
groups, to be able to simultaneously condition and prime dentin.
(81) This approach eliminates the
rinsing step, resulting in shortening of the clinical application time and reducing the techniquesensitivity of the adhesive system application. (71) Also, the infiltration of monomers occurs
simultaneously with the self-etch process eliminating the possibility of discrepancies between
15
both processes and reducing the presence of unprotected collagen fibrils, which in turn reduces
nano leakage. (41)
All self-etch adhesives incorporate water as a solvent in their composition in order to allow the
ionization of the incorporated acidic monomers to be capable of etching the tooth structure.
(82)
Self-etching adhesives, only dissolve the smear layer without removal of the dissolved calcium
phosphates since the rinsing step is eliminated.
(70, 71) They can be classified according to their
acidity and etching power into strong (pH ≤ 1), intermediate strong (pH≈1.5), and mild
(pH≥2).
(70)
Strong self-etch adhesives dissolve more hydroxyapatite crystals that become embedded within
the interfacial zone. At the enamel level, the etching pattern is similar to that of phosphoric acid
treatment used in the total etch approach. (83) At the dentin level, the collagen network is exposed
and nearly all the hydroxyapatite crystals are dissolved to a depth of 3 μm similar to what
happens in the total etch approach, and the transition of the exposed collagen network to the
underlying unaffected dentin is quite abrupt.
(70)
Strong self-etch adhesives are associated with low laboratory and clinical dentinal bonding
performance, especially at the dentin substrate.
(72, 84, 85) This may be due to the soluble calcium
phosphates that are embedded in the interfacial zone.
(72) Also, the high concentrations of acidic
resin monomers make these adhesives behave like hydrophilic permeable membranes and allow
water movement from dentin to the restoration-adhesive interface.
(81, 86) In addition, the residual
solvent that remains within the adhesive interface can weaken the bond.
(70)
Mild self-etch adhesives (pH≈2) dissolve fewer calcium phosphates. At the enamel level, the
etching pattern is very weak and results in weak micromechanical bonding. At the dentin level,
the surface is only partially demineralized to a depth of 1 μm, creating micro-porosities sufficient
for micro-mechanical interlocking, with a substantial amount of hydroxyapatite crystals
remaining undissolved and protecting the collagen fibrils and adhesive interface from early
hydrolytic reactions. (87, 88) These hydroxyapatite crystals also serve as receptors for additional
chemical bonding.
16
Functional monomers with specific phosphate groups, such as phenyl-P (2-methacryl- oxyethyl
phenyl hydrogen phosphate), and 10-MDP (10-methacryloxydecyl dihydrogen phosphate) or
carboxylic groups such as 4-META (4- methacryloxyethyl trimellitic acid), are capable of
chemical bonding with calcium of the residual hydroxyapatite crystals through primary ionic
binding.
(89, 90) 10- MDP results in more effective and hydrolytically stable chemical bonds as
opposed to other functional monomers such as 4-META and phenyl- P (2- methacryloyloxyethyl
phenyl phosphoric acid).
(89)
Intermediately strong adhesives have a pH value about 1.5 and cannot be classified as mild or
strong self-etching adhesives. This results in better micromechanical interlocking than mild selfetching adhesives, at enamel and dentin levels. The resulting demineralized layer is 2.5 μm in
thickness that has its surface totally demineralized whereas the base contains residual
hydroxyapatite crystals that allow for chemical interactions, and thus the transition of the
exposed collagen network to the underlying unaffected dentin is more gradual.
(70)
The interaction between self-etch adhesives and collagen is better than that occurring between
etch-and-rinse adhesives and collagen, which increases the chances for chemical bonding
between residual hydroxyapatite crystals and monomeric groups to enhance bonding. (70)
The resultant two-fold micro-mechanical and chemical bonding mechanism is believed to be
advantageous in terms of restoration durability. The micro-mechanical bonding component
provides resistance to abrupt de-bonding stress while the chemical bonding provides resistance to
hydrolytic breakdown. (71, 91)
Two-step self-etch adhesive systems involve the use of a hydrophilic self-etch primer followed
by the application of a more hydrophobic adhesive resin. This results in a more hydrophobic
interface and allows better bond durability. (92) One-step self-etch adhesives are simpler and fast
to use but they show lower bonding efficiency compared to two-step self-etch adhesives. This
may be related to their inferior mechanical properties, a lower degree of conversion, and
increased water sorption by osmosis from dentin. (72, 93)
17
5.3.Universal adhesive or multi-mode:
The system was introduced in 2011 and called universal adhesive or multi-mode because they
can be used as self-etch, etch-and-rinse, or selective-etch systems.
(94) The universal adhesive has
a 10-methacryloyloxydecyl dihydrogen phosphate [MDP] that stimulates a solid adhesion to the
tooth surface by forming a non-soluble Ca2 salt. This system has Dipentaerythritol pentaacrylate phosphate ester and polyalkenoic acid, which are helpful in chemically bonding the
resin.
(82) Therefore, adhesives have the ability to bond methacrylate-based restoratives, cement,
and sealant materials to dentin, enamel, glass ionomer, and several indirect restorative substrates,
including metals, alumina, zirconia, and other ceramics. All are modeled after self-etch systems
and contain acidic monomers. The primary use of these adhesives is with light-activated resin
composites indirect restorations. Nevertheless, because of the limited thickness of the adhesive
layer, they can also be used to lute indirect restorations with self- or dual-cure composites and
cements in combination with a self-cure activator.
(82)
6. Resin Cement:
Clinically, resin cements are becoming very popular due to their ability to bond to the tooth
structure and the indirect restorations strongly. They have high mechanical properties and the
lowest solubility compared to the other available cements.
(95, 96)
Resin cements were initially based on the chemistry of acrylic resins that improved with time
due to further developments in composite resins and adhesive systems. There are two main
categories of resin cement: those requiring the use of an adhesive system (adhesive-based resin
cements), and those that don’t require the use of any adhesive system (self-adhesive resin
cements).
(97, 98)
6.1.Adhesive-Based Resin Cement:
These are composite resin cements that require the application of an adhesive system prior to the
application of the cement. They can be classified according to the method used to activate
18
polymerization: light-cured, self-cured and dual-cured. They can also be classified according to
the adhesive system used: total-etch and self-etch resin cement systems.
(95, 97)
Since the 1970s, adhesive-based resin cements have been available as a two-paste system. Once
the adhesive system has been applied to the tooth structure, the resin cement is mixed according
to the manufacturer's instructions and applied to the intaglio surface of the treated indirect
restoration.
(95, 99, 100) Their composition is usually a mixture of dimethacrylate oligomers,
inorganic fillers, and polymerization initiator. These components are adjusted to maintain low
film thickness and appropriate working and setting time.
(99)
Self-cured adhesive-based resin cements are mainly indicated for cementation of metallic
restorations, metal-ceramic restorations, and posts.
(101) Their use in dentistry is very limited as
they have several disadvantages such as their limited working time, their color instability as their
aromatic amines accelerator oxidizes with time and changes the cement color to a more yellow
shade, and their difficulty in mixing uniformly resulting in nonuniform curing of the cement and
thus lower mechanical properties. Light-cured adhesive-based resin cements provide extended
working time, but their use is limited to the cementation of laminate veneers or shallow inlays,
where curing light can pass through the restoration and initiate polymerization of the cement.
(102,
103)
Dual-cured adhesive-based resin cements can be used in situations where the restoration might
block the curing light from reaching deeply.
(104) Usually supplied as two-paste systems, where
one of the pastes contains the photo-initiator and the chemical activator (reducing amine), while
the other paste contains the chemical initiator, which is usually benzoyl peroxide.
(99, 105) An
interesting feature of these dual-cured cements is that polymerization is accelerated after the
restoration placement when the surrounding environment is deprived of the ambient oxygen
supply. This ambient oxygen feature provides extended working and setting times before
placement of the restoration.
(9) Immediate light curing of the dual cure cements may negatively
limit the self-cure mechanism which may adversely affect the mechanical properties of the
cement, which is why it is recommended in these cements to allow time for the self-curing
mechanism to occur, followed by the light cure mechanism that augments the whole
polymerization process to reach the best mechanical properties.
(106) The ideal time frame between
19
mixing and the light-activation has not yet been determined, but some studies have shown that
light-curing 5 to 10 minutes after mixing does not seem to interfere with final properties, at least
for most of the cements evaluated.
(99)
Without the light curing step, the dual cure cements will act similar to exclusively self-cure
cements and will require more time to cure, which might allow for the transudation of water
from dentin to occur and adverse hydrolytic reactions to take place.
(99, 107)
6.2.Self-Adhesive Resin Cements:
Self-adhesive resin cements were introduced to the dental market in 2002 with the aim of
providing an alternative to adhesive-based resin cements.
(108) These cements are composite resins
that can adhere to tooth structure without the need for adhesive or etching process.
(108, 109) They
combine features of restorative composites, self-etching adhesives and dental cements. They
were introduced to dentistry as a subgroup of resin cements and have gained popularity.
(110)
Rely X Unicem from 3M ESPE represents the first of this new class of materials. Now several
self-adhesive resin cements are available in the dental market. They differ in terms of
composition, working/setting time, number of shades available, and the delivery system.
(98, 111)
All the current self-adhesive resin cements consist of two pastes that require hand-mixing, automixing or capsule trituration. Once the cement is mixed, it can be applied in a single clinical
step.
(97, 112)
The major benefit of these materials is their simplicity of application. According to the
manufacturer’s information, no post-operative sensitivity is expected as the smear layer is not
removed. These cements are claimed to be moisture tolerant, and some are capable of releasing
fluoride ions in a manner comparable to glass ionomer cement.
(97, 109) Also, they offer good
esthetics, adequate mechanical properties, and dimensional stability similar to other categories of
resin cements.
(97, 109)
Available self-adhesive resin cements are dual-curing radiopaque materials that are indicated for
adhesive cementation of any indirect restoration whether it is ceramic, composite or metal.
(108,
20
110) Clinicians generally prefer adhesive-based light-curing materials as opposed to self-adhesive
for luting veneers, due to the need for the longer working time offered by the light-curing
procedure, which allows them to position and adjust several veneers simultaneously, prior to
initiation of the cement polymerization.
(108, 110)
Self-adhesive resin cements utilize monomers with functional acidic groups to demineralize the
tooth structure. These monomers are mainly methacrylate monomers with either carboxylic acid
groups, as with PMGDM (pyromellitic glycerol dimethacrylate) and 4- META, or phosphoric
acid groups, as with 10 -MDP (10-methacryloxydecyl dihydrogen phosphate), Phenyl-P (2-
methacryloxyethyl phenyl hydrogen phosphate), Penta- P (dipentaerythritol pentaacrylate
monophosphate) and BMP (Bis 2-methacryloxyethyl acid phosphate).
(108, 111)
The concentration of these acidic monomers in self-adhesive resin cement is balanced to be low
enough to avoid excessive hydrophilicity in the resulting polymer and high enough to have a
proper degree of self-etching property.
(111) Once the self-adhesive resin cement is mixed, it
shows high initial hydrophilicity, which facilitates its wetting and adaptation to the tooth
structure. The acidic groups react with the calcium of the tooth structure and the metal oxides
released from the ion-leachable fillers.
(111) The material becomes more hydrophobic as the acidic
groups are consumed throughout the reaction. The adhesion obtained is due to micromechanical
interlocking with tooth structure and chemical bonding between the acidic monomers and
hydroxyapatite.
(111)
7. Bonding Testing:
Variations and advances in adhesive materials have made in-vitro bond testing of great
importance. The most common laboratory tests to evaluate the bonding strength of different
adhesives to the tooth substrate are tensile and shear bond strength tests.
(113) However, studies
have shown that the variability in specimen geometry, loading conditions, and material
properties have a significant effect on the tensile and shear testing results.
(114) For more clinically
relevant in-vitro bonding test the crown pull-off test has been used.
(115) (Figure 3)
21
7.1.Micro Tensile Test:
The micro tensile bond-strength (μTBS) test was developed in 1994 to overcome some of the
limitations of macro-tests.
(90) The tested bonding area is about 1mm2 or less, which gave the
μTBS test several advantages including better economic use of teeth since multiple specimens
can be obtained from one tooth, better stress distribution at the bonding interface with more
adhesive failures thereby avoiding cohesive failure in the tooth substrate or restoration, and the
ability to compare a variety of substrates and areas within the same tooth (e.g. peripheral versus
central dentin).
(90, 116-118)
.
However, several protocols are being used in specimen preparation for micro tensile testing and
are classified into trimming and non-trimming protocols. The trimming protocol is more
technique-sensitive than the non-trimming one. Each protocol has its own advantages and
drawbacks.
(119, 120)
Non-trimmed micro specimens are easier and faster in preparation, where the bonded specimens
are sectioned into rectangular bars 0.5–1.5 mm in thickness. Micro specimens trimmed to a
dumbbell or hourglass shape show better stress concentration at the adhesive interface.
Moreover, trimming has to be carefully performed, otherwise interfacial defects may occur and
act as stress concentrators facilitating crack-propagation when the specimen is loaded in tension,
causing premature failure at the interface with a lower recorded bond strength. (121)
Trimming the interfaces freehand using a dental handpiece is a very difficult and techniquesensitive procedure that is dependent on the operator's skill.
(119, 120, 122) Semi-automatic trimming
of micro-specimens can be achieved using the so-called micro specimens former (University of
Figure 3: Bonding Tes0ng Method Including Tensile, Shear, Pull-away
22
Iowa, Iowa City, IA, USA) to trim rectangular specimens in a standardized well- controlled
manner, into dumbbell-shaped specimens or specimens with a circular cross-section.
(121, 123)
Also, more factors need to be standardized within the test settings such as attachment of
specimen to the jig, alignment of specimens, and loading speed. (122) Otherwise, these factors will
influence the outcome of the testing procedure by changing the direction and the severity of the
loading applied. (122, 124, 125)
The number of recorded pre-testing failures is a major point of debate in the current literature
regarding the μTBS testing.
(126) Three main approaches have been applied to manage the pretesting failures: One is to ignore pre-testing failures from statistical analysis, which results in
overestimated bond strength results. Another assigns a zero MPa bond strength value to every
pre-testing failure record. However, this is non-realistic as there is a certain initial bond strength,
which in turn penalizes the tested product severely. The third approach is a modification of the
previous one by assigning a certain pre-determined value to every pre-testing failure. This value
can be the lowest μTBS testing value measured within the respective group.
(127, 128) These
approaches have obvious effects on the mean μTBS value and the subsequent statistical analysis.
Certainly, micro-specimen processing should be performed as carefully as possible and special
measures should be utilized to avoid pre-testing failures. The measures include the use of
materials such as alginate or gypsum to fill up the spaces between the slabs, which results in
better support for the slabs during the second cutting stage.
(72) Several studies have shown that
μTBS testing appears to be able to discriminate between adhesives regarding their bonding
performance in a better way than the traditional shear and tensile bond strength tests. This is
likely why up to 60% of current scientific papers reporting on bond strengths have employed the
μTBS approach.
(72)
7.2.Micro Shear Test:
In 2002, the micro shear bond strength test (μSBS) was introduced as an alternative to the micro
tensile test. (129-131) In the micro shear test, the load is applied to the adhesive interface using a
blade attached to a universal testing machine to induce shearing forces.
(131, 132) Shimida et al.
23
modified the micro shear test settings by using a looped orthodontic wire instead of using a
blade.
(133) In a study by Foong et al. on bond strength to enamel, using the orthodontic wire to
apply shearing forces was easier and more reliable in comparison to using a blade.
(132)
In the micro shear test, it is possible to test several specimens per tooth and the bonding area can
be controlled using microbore (tygon) tubes.
(132, 134) However, when testing the micro shear bond
strength of composite resins to the tooth structure, considerable bending and non-uniform stress
distribution within specimens can occur as a result of the relatively thick adhesive layer
compared to the composite resin cylinder of 0.7-1.0 mm in diameter.
(132, 134) This non-uniform
stress distribution is more pronounced than the conventional shear test.
(134) Furthermore, it is
impossible to confine the adhesive resin to the bonding area. As a consequence of these
shortcomings, the μSBS test has been used in only 7% of the recent bond strength studies.
(72)
In a recent study comparing micro shear and micro tensile tests, the micro shear bond strength
values were about 1/3 of the micro tensile values, and there was no difference in the mode of
failures.
(135) Another study has shown that micro shear test is more accurate in the evaluation of
the bond strength compared to the micro tensile test since the former was associated with more
adhesive failures.
(72, 136)
7.3.Retention Testing:
Retention tests were developed in the 1970ꞌs to simulate the clinical condition in a better way
than bond strength tests. In retention tests, whole crowns are made and cemented to the
underlying tooth substrate and then subjected to pull-away forces to detach from the underlying
substrate. (115)
The main advantage of the retention tests over the bond strength tests is that take into account the
complex configuration of the substrate to which the crown is cemented, unlike the bond strength
tests that consider the substrate as a one-surface flat area.
(115) Studies that compare.
both the retention of the crowns and the bond strength results of dental cements are lacking in the
dental literature.
24
The configuration factor (C-factor) is the ratio between the bonded surfaces and non-bonded
surfaces. The higher the value of the configuration factor, the greater are the stresses induced at
the bonded interfaces as a result of polymerization shrinkage.
(137) This configuration factor is
much higher in crowns cemented to their underlying tooth abutments as in the retention tests
assembly, than of composite or ceramic cylinders cemented onto flat substrate surfaces as in
conventional bond strength tests assembly.
(115) Several studies have shown the significant effect
of the configuration factor on adhesion, which might explain the low values obtained from
retention testing in the range of 1–10 MPa compared to those obtained from bond strength
testing in the range of 20–40 MPa.
(138)
Since the development of retention tests, most of the tested crowns were metal crowns modified
with a ring or hook through which the crown could be pulled away from the underlying tooth
substrate.
(139-143) With the developments in the CAD/CAM technology and with further
developments in the ceramic industry, all-ceramic crowns became popular, and several trials
were undertaken in attempts to pull them away from the underlying substrate.
(115, 144-146)
However, pulling away the ceramic crowns from the underlying substrate without causing a
fracture of the crown remained problematic.
Some studies have increased the thickness of the occlusal portion and formed a hole in the
occlusal surface through which a hook could be attached to pull-off the crown. However, failure
rates up to 65% of the specimens were recorded due to specimens fracturing before being
detached from the underlying substrate.
(145)
Other studies have designed CEREC crowns with the pull-off loop as an integral part of the
crown structure. However, failures related to fractures of the loop during the pull-off were
reported.
(145) Other studies have attached macro-retention features to the crown design, by
modifying the shape of the crown to have bars projecting from it, either from the occlusal surface
or from the sides of the crowns, or by making the crown conical in shape. Failures were recorded
in those crowns with bars on the occlusal surface, however, no failure was mentioned with the
conical-shaped crowns or with crowns having bars projecting from their sides.
(144, 146, 147)
25
Another main issue is the effect of the surface area on the retention test results. Some studies did
not measure the surface area and just distributed the teeth to groups based on their type so that
the groups had either molars or premolars.
(141, 148) Another study measured the size of teeth and
divided them into three groups: small, medium, and large. The teeth were assigned into equal
testing groups so that every group had the same size distribution.
(145) These studies only
measured the force required to dislodge the crowns from their underlying substrate.
(141, 145, 148)
Other Studies tried to measure the surface area using a correlation method, where the weight of
tin foil wrapped around the prepared surface was correlated to the weight of stander tin foil of a 1
cm2 cross-section area.
(146, 149) Other studies attempted to calculate surface area based on the
approximate size of the occlusal surface and compared it with standardized circles of known
surface area and perimeter.
(143, 144, 150) All these studies gave an approximate estimate of the
surface area. Retention tests are time-consuming and require a large number of extracted teeth.
Several factors can affect the outcome of these tests, such as the surface area of the preparation,
the method used to pull the crowns, standardized preparations, and the aging method.
(115)
26
8. Objective:
An abundant amount of research investigated the Bonding properties of Composite Lava
Ultimate blocks. However, the Bonding strength for the new materials printed permanent crown
VarseoSmile Crown Plus and Ceramic Crown were not investigated. Therefore, we are targeting
at micro tensile bonding strength of those materials in different surface treatments as well as the
effect of thermocycling aging.
9. Aim:
The purpose of this in vitro study is to evaluate the effect of different surface treatments and
artificial aging on the micro tensile bonding strength of “subtractive” material (Lava
Ultimate) as well as “additive” materials (VarseoSmile Crown Plus and Ceramic Crown).
10.Null Hypothesis:
• The type of materials does not affect the micro tensile bond strength.
• The type of surface treatment of the materials does not affect the micro tensile bond
strength.
• Thermal fatigue does not affect the micro tensile bonding strength.
27
Chapter Two: Materials and Method
Figure 4 provides an outline of the testing procedure for evaluating micro tensile bond strength.
The process begins with the study design, which involves selecting testing materials.
Subsequently, cuboid shapes are created by cutting for subtractive material and designing, then
printing for additive materials. Following this, the cuboids are bonded after receiving various
surface treatments. Following that, the specimens are sectioned into sticks and randomly
selected. Half of the specimens underwent micro tensile bond strength testing, while the other
half were subjected to thermocycling before being tested for micro tensile bond strength. Finally,
the data on micro tensile bond strength is statistically analyzed, along with Weibull analysis.
Figure 4: The Process of Testing the Micro Tensile Bond Strength.
28
1. Study Design:
One subtractive(milled) resin nanoceramic CAD/CAM block (Lava Ultimate3M ESPE, St. Paul,
MN, USA; color D2-LT) and two additive (printed) resin base CAD/CAM materials (Varseo
Smile Crown Plus, Bego, Bremen, Germany ;Color A1; Ceramic crown , Sprintray, Los Angeles,
CA, USA; Color A1) were selected (Figure 5). The CAD/CAM materials used in this in vitro
study are described in (Table 1).
Table 1: Material Composition
Product Manufacture Composition Lot Number Shade
Lava
Ultimate
3M™ESPE™
(151)
Cured dental restorative, consisting of silica nanomers (20 nm),
zirconia nanomers (4–11 nm), nanocluster particles derived from the
nanomers (0.6–10 nm).
silane coupling agent, and resin matrix (Bisphenol A-diglycidyl
dimethacrylate (BisGMA), ethoxylated bisphenol A dimethacrylate
(Bis-EMA), urethane dimethacrylate (UDMA) and Triethylene
glycol dimethacrylate (TEGDMA).
N 642103 D2-
LT
VarseoSmile
Crown Plus BEGO(152)
Esterification products of 4.4'-isopropylidiphenol, ethoxylated and
2-methylprop-2enoic acid. Silanized dental glass,
methylbenzoylformate, diphenyl (2,4,6-trimethylbenzoyl) phosphine
oxide.
Total content of inorganic fillers (Particle size 0.7 μm) is 30 – 50 %
by mass.
600577 A1
Ceramic
Crown
SprintRay(153) Oligomers 20% - 60% , Monomers 20% - 50% ,Photoinitiators 0.1%
- 10%, Additives 10% - 60%
LBL-2057-1 A1
Figure 5: Resin Base CAD/CAM Materials: (A) Lava Ul0mate,(B) VarseoSmile Crown Plus ,and (C) Ceramic Crown
29
RelyX
Ultimate
3M ESPE™ (151) Base paste: Silane--treated glass powder, 2-propenoic acid, 2-
methyl-, reaction products with 2-hydroxy-1,3-propanedyl
dimethacrylate and phosphorus oxide, TEGDMA, silane--treated
silica, oxide glass chemicals, sodium persulfate, tertbutyl peroxy3,5,5- trimethylhexanoate,
copper acetate monohydrate
Catalyst paste: Silane-treated glass powder, substituted
dimethacrylate, 1,12-dodecane dimethacrylate, silane--treated silica,
1-benzyl-5-phentyl-barbic-acid, calcium salt, sodium ptoluenesulfinate, 2-propenic acid, 2-methyl-, di-2,1-ethanediyl ester,
calcium hydroxide, titanium dioxide
3100011406 TR
Monobond
®Plus
Ivoclar
Vivadent(154)
Phosphoric acid methacrylate, silane methacrylate, disulfide
methacrylate, ethanol
Z04RWS
Scotchbond
Universal
Adhesive
plus
3M ESPE™(155) MDP Phosphate Monomer, Dimethacrylate resins, hydroxyethyl
methacrylate (HEMA), VitrebondTM Copolymer , Filler, Ethanol,
Water, Initiators , Silane
9505278
This in-vitro study investigated a total of (n=1200) stick specimens; (n=400) for each
CAD/CAM material. Each material group was subdivided into two Aging: (1) non-aged, and (2)
Aged with thermocycling. Then each CAD/CAM material group was investigated following
eight different surface treatments: (1) Control, (2) Airborne particles abrasion, (3) Silane, (4)
Adhesive, (5) Airborne particles abrasion+ silane, (6) Silane + Adhesive, (7) Airborne particles
abrasion+ Adhesive, and (8) Airborne particles abrasion+ silane +Adhesive. All specimens were
subjected to µTBS in the universal testing machine (Figure 6).
30
Figure 6: Study Design
31
2. Specimen Fabrication and Preparation
Cuboid-shaped objects were fabricated by either cutting or printing them. Then the bonding
surface of these objects was polished, and a dedicated surface treatment was applied. Two
objects made from the same material and with the same surface treatment were bonded together.
Then the bonded objects were sectioned into sticks then tested for micro tensile bond strength,
either with or without artificial aging (Figure 4). Tested specimens analyzed for failure mode and
statistical analysis was performed.
2.1.Object Fabrication
2.1.1. Subtractive Material (Milled):
Resin nanoceramic blocks (Lava Ultimate, 3M ESPE, St. Paul, MN, USA; color D2-LT, size
14×14×18 mm) were mounted into a precision low-speed diamond saw (IsoMet 1000, Buehler,
Lake Bluff, IL, USA) then cut into 16 cuboid shapes with a size of 14 × 14× 5 mm and 14 ×
14× 6 mm using a diamond blade (102 mm diameter, 0.3 mm thickness; IsoMet Blade 15LCA,
Buehler, Lake Buff, IL, USA ) under constant cooling with distilled water (Figure 7). Followed
by polishing the cuboid objects to remove the irregularities 24 hours prior to cementation, The
details are mentioned below.
Figure 7: Lava Ultimate Block Section Into 3 Cuboid by Precision Low-Speed Diamond Saw.
32
2.1.2. Additive Materials (Printed):
Two additive materials were used in the study. Each material is printed and post-processed
according to the manufacturer’s recommendation. For all additively manufactured materials, an
open source three-dimensional (3D) design software (Meshmixer, Autodesk, San Francisco, CA,
USA) is used to design a flat cuboid object with the measurements 14 × 14 × 5 mm and 14 × 14
× 6 mm (same shape and size as subtractive material; Figure 8). The resulting 3D object exported
to a Standard Triangle Language (STL) file for the printed resin. For each printing material, 16
cuboid objects were printed on the manufacturer-recommended stereolithography (SLA) printing
device. Details for the printing procedure varied between different materials.
VarseoSmile Crown Plus(Bego, Bremen, Germany; Color A1): The manufacturerrecommended digital light processing (DLP) printer (Sprintray pro 95, Los Angeles, CA, USA)
was used. The STL files were imported into a slicing program (Ray ware, Sprint Ray, Los
Angeles, CA, USA) Then they were exported into a slicing file and transferred to a digital printer
(Sprint Ray Pro 95, Los Angeles, CA, USA) using a portable hard drive. The resin material was
mixed thoroughly by handshaking for 2 min before pouring it into the printer. When the printer
finished printing the objects were removed from the platform using a stainless-steel spatula
(Sprintray, Los Angeles, CA, USA).
Figure 8: Cuboid Object Design Using Meshmixer (A) 14 × 14 × 6 mm ,(B) 14 × 14 × 5 mm
33
Pre cleaning: in fresh 96% alcohol solution (Solimo, Seattle, Washington USA) for 3 min in an
unheated ultrasonic bath (wash and cure Machine, Anycubic, Shenzhen, Guangdong, China).
Cleaning: change the solution with a fresh 96% alcohol solution (Solimo, Seattle, Washington
USA) for 2 min in an unheated ultrasonic bath (wash and cure Machine, Anycubic, Shenzhen,
Guangdong, China) and clean with a toothbrush (Sunstar G.u.m, Chicago. IL.USA). Then the
cleaned objects were air-dried.
Post curing: Pre-cleaned objects were subjected to an additional curing step by placing them
curing device (Sprintray Pro-cure, Los Angeles, CA, USA) with an exposure of 2 cycles for 20
min each at 20 ºC. Then the post-cured objects were allowed to cool down to room temperature
for 3–5 min (Figure 9). This was followed by polishing the cuboid objects to remove surface
irregularities and standardize the surface 24 h prior to cementation. The details are mentioned
below.
Ceramic crown (Sprint Ray, Los Angeles, CA, USA; Color A1): The manufacturerrecommended digital light processing (DLP) printer (Sprint Ray pro 55 S, Los Angeles, CA,
USA) was used. The STL file was imported into a slicing program (Ray ware, Sprint Ray, Los
Angeles, CA, USA). Then it was exported into a slicing file and transferred to a digital printer
(Sprint Ray pro55 S, Los Angeles, CA, USA) using a portable hard drive. The resin material was
thoroughly mixed by handshaking for 2 min before pouring it into the printer. When the printer
Figure 9: VarseoSmile Crown Plus Specimen Prepara0on
34
finished printing the objects were removed from the platform using a stainless-steel spatula
(Sprint ray, Los Angeles, CA, USA).
Precleaning: in fresh 96% alcohol solution (Solimo, Seattle, Washington USA) for 3 min in an
unheated ultrasonic bath (Sprint Ray Pro Wash/Dry, Sprint Ray, Los Angeles, CA, USA).
Followed by Cleaning: Change the solution with a fresh 96% alcohol solution (Solimo, Seattle,
Washington USA) for 2 min in an unheated ultrasonic bath (SprintRay Pro Wash/Dry) and
cleaned with a toothbrush (Sunstar G.u.m, Chicago, IL, USA). Then the cleaned objects were airdried.
Post curing: Pre-cleaned objects were subjected to an additional curing step by placing them
curing device (ProCure 2 Automated Post-processing, Los Angeles, CA, USA) with automated
sittings. Then the post-cured objects were allowed to cool down to room temperature for 3–5
minutes. (Figure 10) Followed by polishing the cuboid objects to remove surface irregularities
and standardize the surface 24 hours prior to cementation. The details are mentioned below.
Figure 10: Ceramic Crown Specimen Prepara0on
2.2.Polishing:
The bonding surface of all fabricated objects (subtractively and additively fabricated) was
polished to remove any irregularities, scratches, and other surface defects as well as to
standardize the bonding surface. For this purpose, abrasive silicon carbide paper (Carbimet,
35
Buehler, Lake Bluff, IL, USA) with differing grits in ascending order (600, 1000, 1200 grit;
Figure 11) was used under running water. Then, the specimens were cleaned for 10 min in
distilled water using an ultrasonic bath (Ultrasonic Cleaning Systems, Quantrex, Kearny, NJ,
USA), followed by air drying. Specimens were stored at room temperature in a clean and closed
container before further processing for 24 h maximum.
Figure 11: Polishing Papers and The Bonding Surface AUer Polishing
2.3.Treatment of the Bonding Surface:
The materials used in different surface treatments are shown in Table 1. The bonding surfaces of
two cuboids from each material received one of the following surface treatments within 24 hours
of polishing and cleaning:
1. Control (C): No surface treatment was performed. The bonding was be performed on the
polished and cleaned surfaces.
2. Air-Borne Particle Abrasion (P): The polished and cleaned surface was treated with airborne Particle abrasion. To ensure uniform abrasion of the entire bonding surface, the
bonding surface was painted completely with one coat using a black permanent marker
(Sharpie, Worcester, MA, USA). Airborne Particle abrasion using 50 μm aluminum oxide
particles (Cobra, Renfert, Hilzingen, Germany) in a sandblasting unit (Basic Classic, Renfert,
Hilzingen, Germany) at pressure 2.5 bar(156) was performed. A metal pin was attached to the
nozzle of the blasting unit to always maintain an even distance of 10 mm. The Particle stream
36
was directed over the surface in a scanning pattern from left to right from the top of the
bonding surface to the bottom until the permanent marker marks were removed completely
(Figure 12). Then, the specimens were cleaned for 10 min in distilled water using an
ultrasonic bath followed by air drying.
3. Silane (S): One drop of silane coupling agent (Monobond Plus, Ivoclar vivadent, Schaan,
Liechtenstein) was applied and spread evenly over the entire polished and cleaned surface
using a micro-brush (Maxmicro Micro Brush Applicators, Plasdent, Novi, MI, USA). The
silane was left for 60 s; then any excess solvent was evaporated using air from air pressure
(Figure 13).
4. Adhesive (A): One drop universal adhesive (Scotchbond Universal Plus, 3M, St. Paul, MN,
USA) applied and spread evenly over the entire polished and cleaned surface using a microbrush (Maxmicro Micro Brush Applicators, Plasdent, Novi, MI, USA] air dried for 5 s to
evaporate the solvent at a distance of 10 mm until there was no movement in the adhesive.
Figure 12: Airborne Par0cle Abrasion Treatment
Figure 13: Silane Surface Treatment
37
Then, the adhesive was photopolymerized using a polywave LED curing unit (Valo, Ultra
dent, South Jordan, Utah, USA) for 20 s in standard mode. The lens of the curing unit was
placed parallel to the bonding surface at a 1 mm distance.(157)
(Figure 14)
5. Air-borne Particle abrasion + silane (PS): The polished and cleaned surface was treated
with air-borne Particle abrasion. To ensure uniform abrasion of the entire bonding surface,
the bonding surface was painted completely with one coat using a black permanent marker.
Airborne-Particle abrasion was performed using 50-μm aluminum oxide particles in a
sandblasting unit at a pressure 2.5 bar. (156) A metal pin was attached to the nozzle of the
blasting unit to maintain an even of 10 mm at all times. The Particle stream was directed over
the surface in a scanning pattern from left to right from the top of the bonding surface to the
bottom until the permanent marker marks were removed completely. Then, the specimens
were cleaned for 10 min in distilled water using an ultrasonic bath, followed by air drying.
Then, one drop of silane coupling agent was applied and spread evenly over the entire
airborne Particle abraded surface using a micro-brush. The silane was left for 60 s; then any
excess solvent was evaporated using compressed air. (Figure 15)
Figure 14: Adhesive Surface Treatment
38
6. Silane + Adhesive (SA): One drop of silane coupling agent was applied and spread evenly
over the photopolymerized adhesive surface using a micro-brush. The silane was left for 60
s; then any excess solvent was evaporated using compressed air. Then, one drop of universal
adhesive was applied and spread evenly over the entire polished and cleaned surface using a
micro-brush. The adhesive was air dry for 20 s, then photopolymerized the adhesive by
placing the tip of a LED curing unit parallel to the bonding surface in a 1 mm distance and
photo-polymerized for 20 s in standard mode (1000 mw/ cm2).
(157)
(Figure 16)
7. Air-borne Particle abrasion + adhesive (PA): The polished and cleaned surface was
treated with air-borne Particle abrasion. To ensure uniform abrasion of the entire bonding
Figure 15: Airborne Par0cle Abrasion + Silane Surface Treatment
Figure 16: Silane + Adhesive surface treatment
39
surface, the bonding surface was painted completely with one coat using a black permanent
marker. Airborne Particle abrasion was performed using 50-μm aluminum oxide particles in
a sandblasting unit (Basic Classic, Renfert, Hilzingen, Germany) pressure of 2.5 bar(156)
. A
metal pin was attached to the nozzle of the blasting unit to ensure maintaining an even of 10
mm at all times. The particle stream was directed over the surface in a scanning pattern from
left to right from the top of the bonding surface to the bottom until the permanent marker
marks are removed completely. Then, the specimens were cleaned for 10 min in distilled
water using an ultrasonic bath, followed by air drying with compressed air. Then one drop of
universal adhesive was applied and spread evenly over the entire air abraded surface using a
micro-brush. The adhesive was air dried with compressed air for 5 s to evaporate the solvent
then photopolymerized the adhesive by placing the tip of a LED curing unit parallel to
bonding surface in a 1 mm distance and photo-polymerized for 20 s in standard mode (1000
mw/cm2
; Figure 17).
(157)
8. Air-borne Particle abrasion + silane + adhesive (PSA): The polished and cleaned surface
was treated with air-borne Particle abrasion. To ensure uniform abrasion of the entire
bonding surface, the bonding surface was painted completely with one coat using a black
permanent marker. Airborne-Particle abrasion was performed using 50-μm aluminum oxide
Figure 17: Air-Borne Par0cle Abrasion + Adhesive Surface Treatment
40
particles in a sandblasting unit at pressure 2.5 bar.
(156) A metal pin was attached to the nozzle
of the blasting unit to maintain an even of 10 mm at all times. The particle stream was
directed over the surface in a scanning pattern from left to right from the top of the bonding
surface to the bottom until the permanent marker marks were removed completely. Then, the
specimens were cleaned for 10 min in distilled water using an ultrasonic bath, followed by air
drying with compressed air. Then, one drop of silane coupling agent was applied and spread
evenly over the entire airborne particle abraded surface using a micro-brush. The silane was
left for 60 s; then any excess solvent was evaporated by compressed air. Then one drop of
universal adhesive was applied and spread evenly over the entire silanated surface using a
micro-brush. The adhesive was air dried for 5 s to evaporate the solvent then
photopolymerized the adhesive by placing the tip of an LED curing unit parallel to the
bonding surface at 1 mm distance and photo-polymerized for 20 s in standard mode (1000
mw/ cm2;Figure 18).
(157)
2.4.Bonding Procedure:
The bonding procedure was performed immediately after the surface treatment was applied as in
the (Figure 19). The two cuboid objects from the same materials that received the same surface
treatment bonded together resulting in a bilayered bonded object.
(151, 158) One of the two cuboid
Figure 18: Air-Borne Par0cle Abrasion + Silane + Adhesive Surface Treatment Steps.
41
objects was placed in a custom-made seating device with the bonding surface facing up. A 5-mm
long line of a dual cure resin-cement (RelyX Ultimate, shade TR, 3M ESPE, St. Paul, MN, USA)
was placed in the middle of the bonding surface using the automix tip attached to the cement
syringe. Then, the cement spread out over the surface using a micro brush. The corresponding
cuboid object’s bonding surface facing down and positioned onto the resin cement. All sides of
the cuboid objects have to be lined up with each other. Then, a fixed load of 1 kg was applied to
ensure uniform loading of all specimens during the bonding process.
As a seating device, a dual-axis chewing simulator was used (CS-3-8; SD Mechatronik,
Feldkirchen –Westerham, Germany). Excess cement was cleaned with a micro-brush (Maxmicro
Micro Brush Applicators). After 2 minutes, the bonding surfaces photo-polymerized from all four
surfaces by placing the tips of two LED curing units (Valo, Ultra dent, South Jordan, UT, USA.)
perpendicular to the bonding surface, opposing each other at a 1 mm distance. Each side of the
bonded objects photo-polymerized twice for 20 s in standard mode (1000 mw/ cm2). For each
material, the irradiance was measured with a radiometer (Bluephase Meter II, Ivoclar Vivadent,
Schaan, Liechtenstein). An air-blocking gel (Sterile Lubricating Jelly, Medline, Northfield, IL,
USA) was placed over to the bonding interface, and the specimens light-cured again for 20 s
from all sides. The samples remained in the seating device for 6 minutes before being removed
from the seating device and rinsed with distilled water to remove the air-blocking gel. Then,
bonded bilayered objects were stored in a separate container filled with distilled water for 24 h at
37 ºC in an incubator (5510, National Appliance, Portland, OR, USA) before processing them
further.
42
2.5. Specimen/Stick Fabrication:
The bonded bilayered objects were attached to a printed resin cylinder (25mm*16mm). The
bonded side was parallel to the cylinder and glued using cyanoacrylate adhesive (Zapit, Dental
Ventures of America, Corona, CA, USA). The cyanoacrylate adhesive hardened by spraying on
an accelerator liquid (DVA Zapit accelerators, Dental Ventures of America, Corona, CA, USA.).
Each side of the bonded bilayered objects was painted completely with one coat using a black
permanent marker (Sharpie) to make it easy to identify after cutting. The cylinder was placed in a
custom-made circular holder and secured with inset screws. The holder was installed in the
precision low-speed diamond saw unit (Isomet 1000). Using a diamond blade (102 mm diameter,
0.3 mm thickness; IsoMet Blade 15LCA, Buehler, Lake Buff, IL, USA ), the bonded bilayered
object was cut perpendicular to the bonded surface into 1.00 ± 0.5 mm thick slices under
constant cooling with distilled water. (159) Then, the cut area was supported with wax from both
sides to avoid flexing and breakage, the circular holder was rotated by 90°, and the slices were
cut into sticks with a size of 1.00 x 1.00 ± 0.2 mm. The outermost layer painted with a black
permanent marker (Sharpie) of the cut bilayered objects were discarded. (Figure 20)
Figure 19: Bonding Steps
43
Figure 20: (A) Bilayered object glued to the cylinder by Zap it, (B) Cylinder attached to the circular holder, (C) Mount the holder
to the machine, (D) Cut the sample slices, (E)Rotate the bilayered sample 90° and cut into sticks.
3. Artificial Aging
The sticks obtained from each bonded bi-layered object were divided into two groups (non-aged
and aged). Each subgroup was stored in separate containers. Non-aged sticks were stored in
distilled water for 24 hours before testing. Aged sticks were artificially aged by subjecting them
to thermo-mechanic cycling (20,000 cycles).
3.1.Thermal Fatigue:
The sticks were placed in very fine fiberglass mesh pouches (Doca Screen, Docazoo, Memphis,
TN, USA) to separate each sub-group during thermal fatigue. The specimens were aged by
subjecting them to 20,000 thermo-mechanical cycles (Thermocycler THE-1100, SD
Mechatronik, Westerham, Germany) in distilled water at temperatures of 5 ºC and 55 ºC with 30
s dwell time and 15 s transfer time (Figure 21).
Figure 21: Thermo-Mechanical Cycles in Separate Mesh Pouch for Each Surface Treatments in Each Materials.
44
4. Micro Tensile Bond Strength (μTBS) Testing:
The thickness and width of each stick were measured using a digital caliper (AOS Absolute
Digimatic Caliper, Mitutoyo, Sakado, Japan) prior to testing. Sticks were attached to a custommade testing jig with a cyanoacrylate adhesive (Zapit base pink, Dental Ventures of America,
Corona, CA, USA). Then, the adhesive was hardened by spraying on a chemical accelerator
(Zapit accelerator, Dental Ventures of America, Corona, CA, USA.), and the jig was mounted in
a custom-made holder that was attached to a tensile grip (Pneumatic Side Action Tensile Grips,
Instron, Norwood, MA, USA). The testing tensile grip was mounted in a universal testing
machine (Model 5965 Instron, Norwood, MA, USA), and tensile forces were applied at a
crosshead speed of 0.5 mm/min until the fracture of the attached stick occurred. The load at
failure was recorded in N using the testing software (Bluehill 3, Instron, Norwood, MA, USA).
The µTBS in MPa was calculated by dividing the failure load (N) by the area (mm2
). (Figure 22)
Figure 22: µTBS Testing Steps
5. Failure mode analysis
The type of failure was recorded as adhesive, cohesive, or mixed (Figure 23).
Adhesive failure: failures when the material debonded from the bonding surface with no
remaining adhesive materials in the bonding surface of the tested materials.
Cohesive failure: Cohesive failure in cement occurs when the fracture occurs within the cement
and the tested materials with the remaining adhesive layer in the tested material. Cohesive
45
failure in Material when the fracture occurs in the tested material and does not involve the
cement area.
Mixed failure: a combination of any two types of failures. Sticks debonded prematurely before
testing during cutting, thermocycling, or long-term water storage were classified as pre-testing
failures (PTF). They were given a bond strength value of 0 MPa, and they were excluded in the
statistical analysis.
Figure 23: (a) Adhesive (interface resin -adhesive), (b) Cohesive in Material, (c) Cohesive in Cement, (d) Mixed Adhesive -Resin
46
6. Statistical Analysis:
6.1.Micro Tensile Bond Strength:
The raw data were exported from Bluehill 3 software (Instron, Norwood, MA, V3.04, Bluehill,
USA), imported into 2023 Microsoft Excel (Excel version 16.78, Microsoft Office, Redmond,
WA, USA), and organized. SPSS 28.0.0 software (IBM SPSS Statistics 28.0.0, SPSS Inc.,
Chicago, IL, USA) was used to analyze the data.
Quantitative variables are described by the Mean, Standard Deviation (SD), Standard Error (SE),
and range (Minimum–Maximum) in a 95% confidence interval of the mean were performed in
SPSS. Shapiro-Wilk test was used to test the normality hypothesis of the µTBS data. Mostly,
parametric tests are used for normally distributed data. Levene’s test was used to check the
homogeneity of variances.
SPSS General Linear Model (GLM) measures ANOVA was used to analyze the main variables
(material, Surface treatment, and Aging) and their interactions. For multiple comparisons posthock test, the Bonferroni Method is applied. In the case of multiple analyses on the same
variable, Bonferroni correction, also known as Bonferroni type adjustment, is important because
the probability of committing a Type I error increases, thus increasing the likelihood of getting a
significant result by pure chance. A Bonferroni correction is conducted to correct or protect from
Type I error. The significance level was considered at ⍺=0.05.
There is a Bonferroni-adjusted significance test for pairwise comparisons in SPSS. Post hoc tests
and estimated marginal means can both use this adjustment. To begin with, a desired alpha level
is divided by the number of comparisons. Second, it uses the number calculated as the p-value
for determining significance. So, for example, with alpha set at 0.05 and with three comparisons,
the p-value required for significance would be 0.05/3 = 0.0167. This is an unadjusted p-value. To
obtain the corrected p-value, SPSS multiplies the unadjusted p-value of .016 by 3, which equals
0.048. Since this value is less than 0.05, it would conclude that the difference was significant.
47
6.2.Weibull Analysis:
The Weibull Two-parameter distribution function correlates the cumulative probability of failure
(��) of an area under tensile stress to two-parameter estimates: Weibull modulus (�) that
represents the shape parameter and Weibull characteristic strength (σ�) which represents the
scale parameter. The two-parameter Weibull distribution was found using the following
equation:
Equation 1
�! = 1 − ��� -− .
σ
σO
0
#
1
(��) is the probability of failure, and (�) is the failure stress, which is the µTBS data. (��) is the
Weibull characteristic strength, and (�) is the Weibull modulus. To calculate the Weibull Twoparameter distribution, the specimens (N) in each group (n=25) were ranked in an ascending
order based on the µTBS values and numbered (i) according to their order (1-25). From this
assigned numerical order, � was calculated as the following:
Equation 2
�! = 1 − 4
� − 0.5
� :
Then, the natural logarithms of each specimen were calculated (ln σ), and double natural
logarithm �� as in (Equation 3). Next, the ln σ was plotted on the y-axis and lnln[1/(1−�)] on the
x-axis.
Equation 3
����'1⁄)1 − �!,.
The linear regression equation (Equation 4) gives the shape parameter (�), which is the Weibull
modulus. Thus, the Weibull modulus, (�), is equal to the slope of the linear regression fit.
48
Equation 4
� = �� + ��������
The scale parameter, or Weibull characteristic strength (σo)(the point at which�=62.30% of
failure and σ =0), is obtained by dividing the intercept (�) by �, and reconverting the data by
applying the exponential function. (Equation 5)
Equation 5
�$ = ��� 4
−�
� :
Weibull analysis of the data was performed using R (v4.2.1; R Core Team 2022, PBC, Boston,
MA, USA). The "fitdst" package was used to fit Weibull plots to the data to calculate the
Weibull Characteristic Strength and Weibull Modulus of each group and generate Weibull plots
and likelihood contour plots.
49
Chapter Three: Results
1. Descriptive Analysis of Micro Tensile Bond Strength (µTBS):
A summary of the descriptive statistical analysis of the results showing the mean µTBS and the
standard deviation for the tested materials is shown in Table 2. Overall, the highest mean µTBS
value was seen in Lava Ultimate treated with Airborne Particle Abrasion + Adhesive Non-Aged
group (LU PA.NA; 86.033±16.89 MPa). The lowest mean µTBS value was observed in Lava
Ultimate Control Aged group (LU C.A; 1.547±1.03 MPa) as baseline (Figure 24).
Figure 24: Overall Mean µTBS Values (MPa)
0
10
20
30
40
50
60
70
80
90
Non-Aged
Aged
Non-Aged
Aged
Non-Aged
Aged
Non-Aged
Aged
Non-Aged
Aged
Non-Aged
Aged
Non-Aged
Aged
Non-Aged
Aged
Control Airborne
Particle
Abrasion
Silane Adhesive Airborne
particle
Abrasion +
Silane
Silane +
Adhesive
Airborne
particle
Abrasion +
Adhesive
Airborne
particle
Abrasion +
Silane +
Adhesive
Lava Ultimate VarseoSmile Crown Plus Ceramic Crown
50
For Lava Ultimate before aging, the highest µTBS values were achieved for Airborne Particle
Abrasion + Adhesive (LU PA.NA; 86.033±16.89 MPa) and the lowest for control (LU
C.NA;11.83± 3.78 MPa). After aging, the highest value was found in group Airborne Particle
Abrasion + Silane (LU PS.A; 54.845±13.99 MPa), while the lowest was found in Control ( LU
C.A; 1.55±1.03 MPa).
VarseoSmile Crown Plus treated with Airborne Particle Abrasion + Adhesive showed the highest
overall µTBS values after aging (VS PA .A; 43.258±6.47 MPa) and the lowest for control (VS
C.A; 9.092± 5.25 MPa). However, before aging, the highest mean µTBS value was seen in
surfaces treated with Airborne Particle Abrasion + Silane + Adhesive (VS PSA.NA; 41.96±5.51
MPa), while the lowest was found in Silane (VS S.A; 11.336±5.62 MPa).
Ceramic crown exhibited higher µTBS values after aging surface treatment Airborne Particle
Abrasion + Adhesive (CC PA. A;56.769±9.70 MPa) and the lowest for Control (CC C.A;
16.403± 6.88 MPa). However, before aging the highest mean µTBS value was seen in surfaces
treated with Airborne Particle Abrasion + Silane + Adhesive (CC PA.NA; 56.049±7.65 MPa)
while the lowest was found in Control (CC C.A; 24.727±8.87 MPa).
51
Table 2: Overall Micro Tensile Bond Strength (MPa) of Lava Ultimate, VarseoSmile Crown Plus, and Ceramic Crown
Material Surface Treatment Time Group No.& Name σ Mean σ SD Std.
Error
95% Confidence
Interval Maximum Minimum
Lower
Bound
Upper
Bound
Lava Ultimate
Control
Non-Aged (1) LU C.NA 11.831 3.78 0.76 10.27 13.392 18.11 1.93
Aged (2) LU C.A 1.547 1.03 0.42 0.46 2.63 2.63 0.18
Airborne Particle
Abrasion
Non-Aged (3) LU P.NA 80.557 18.87 3.77 72.77 88.35 107.20 18.55
Aged (4) LU P.A 48.185 13.34 2.66 42.67 53.69 75.94 9.46
Silane
Non-Aged (5) LU S.NA 41.104 16.10 3.22 34.45 47.75 68.36 16.38
Aged (6) LU S.A 17.465 8.86 1.77 13.81 21.12 47.06 6.43
Adhesive
Non-Aged (7) LU A.NA 18.460 5.65 1.13 16.13 20.79 34.53 10.19
Aged (8) LU A.A 3.061 1.89 0.38 2.26 3.85 5.84 0.07
Airborne Particle
Abrasion + Silane
Non-Aged (9) LU PS.NA 81.170 12.77 2.55 75.9 86.44 112.55 60.12
Aged (10) LU PS.A 54.845 13.99 2.8 49.06 60.62 84.69 21.62
Silane + Adhesive
Non-Aged (11) LU SA.NA 21.965 8.16 1.63 18.59 25.33 37.83 1.23
Aged (12) LU SA.A 6.810 3.12 0.64 5.48 8.13 11.69 1.40
Airborne Particle
Abrasion + Adhesive
Non-Aged (13) LU PA.NA 86.033 16.89 3.37 79.06 93.00 113.77 49.48
Aged (14) LU PA.A 41.997 14.17 2.83 36.14 47.85 66.11 6.73
Airborne Particle
Abrasion + Silane +
Adhesive
Non-Aged (15) LU PSA.NA 82.695 10.78 2.16 78.25 87.14 99.54 60.21
Aged (16) LU PSA.A 47.961 12.19 2.43 42.93 52.99 75.51 26.87
VarseoSmile Crown Plus
Control Non-Aged (17) VS C.NA 12.408 6.37 1.27 8.443 16.373 33.25 1.01
Aged (18) VS C.A 9.092 5.25 1.05 6.92 11.26 22.03 .07
Airborne Particle
Abrasion
Non-Aged (19) VS P.NA 41.113 7.25 1.44 38.12 44.11 53.28 27.25
Aged (20) VSP.A 40.664 10.15 2.03 36.47 44.85 72.52 22.26
Silane Non-Aged (21)VS S.NA 11.336 5.62 1.12 9.02 13.65 4.99 26.03
Aged (22) VS S.A 12.832 8.93 1.78 9.14 16.51 40.47 4.33
Adhesive Non-Aged (23) VS A.NA 22.068 10.94 2.18 17.54 26.58 47.57 3.36
Aged (24) VS A.A 17.448 10.45 2.09 13.13 21.76 48.78 8.66
Airborne Particle
Abrasion + Silane
Non-Aged (25) VS PS.NA 38.642 5.65 2.021 36.19 41.08 52.42 29.53
Aged (26) VS PS.A 41.626 5.91 1.18 38.90 44.34 56.29 27.65
Silane + Adhesive Non-Aged (27) VS SA.NA 20.154 12.23 2.44 15.10 25.20 54.96 5.67
Aged (28)VS SA.A 19.252 11.35 2.27 14.56 23.93 47.98 8.43
Airborne Particle
Abrasion + Adhesive
Non-Aged (29) VS PA.NA 40.712 6.48 1.29 38.03 43.38 49.50 27.07
Aged (30) VS PA.A 43.258 6.47 1.29 40.58 45.92 54.49 33.62
Airborne Particle
Abrasion + Silane +
Adhesive
Non-Aged (31) VS PSA.NA 41.955 5.51 1.10 39.68 44.23 55.09 32.93
Aged (32) VS PSA.A 42.148 7.62 1.52 39.00 45.29 57.63 24.41
Ceramic Crown
Control Non-Aged (33) CC C.NA 24.727 8.87 1.77 21.06 28.38 41.26 11.10
Aged (34) CC C.A 16.403 6.88 1.38 13.56 19.24 31.13 5.70
Airborne Particle
Abrasion
Non-Aged (35) CC P.NA 49.233 9.12 1.82 45.46 52.99 70.94 35.57
Aged (36) CC P.A 40.223 11.87 2.37 35.32 45.12 57.83 1.37
Silane Non-Aged (37) CC S.NA 43.482 8.95 1.79 399.79 47.18 56.94 29.33
Aged (38) CC S.A 37.731 12.65 2.53 32.51 42.95 58.57 11.53
Adhesive Non-Aged (39) CC A.NA 44.397 11.22 2.24 39.77 89.02 62.91 15.03
Aged (40) CC A.A 36.576 10.21 2.04 32.35 40.79 55.13 16.02
Airborne Particle
Abrasion + Silane
Non-Aged (41) CC PS.NA 49.026 9.02 1.80 45.31 52.75 63.15 24.42
Aged (42) CC PS.A 56.585 10.58 2.11 52.22 60.95 79.41 32.95
Silane + Adhesive Non-Aged (43) CC SA.NA 47.350 12.19 2.44 42.31 52.38 74.08 25.56
Aged (44) CC SA.A 43.119 12.28 2.46 38.05 48.19 64.90 18.48
Airborne Particle
Abrasion + Adhesive
Non-Aged (45) CC PA.NA 56.049 7.65 1.53 52.884 59.20 40.69 32.82
Aged (46) CC PA.A 56.769 9.70 1.94 52.76 60.77 72.32 30.54
Airborne Particle
Abrasion + Silane +
Adhesive
Non-Aged (47) CC PSA.NA 52.708 11.03 2.21 48.15 57.26 84.96 33.78
Aged (48) CC PSA.A 47.041 4.69 0.94 45.10 48.97 54.86 36.43
52
2. Data Normality Analysis and Equality of Variances:
The Shapiro-Wilk test was used to test the normality of the µTBS values. The test revealed that
the data were not normally distributed; 12 out of the 48 groups deviated from the normality
assumption (p<0.05). (Table 3)
Table 3: Shapiro-Wilk Test (Normality)
Materials Group Shapiro-Wilk
Statistic df Sig.
Lava Ultimate
1- LU Control Non-Aged .972 25 0.70094
2- LU Control Aged .905 6 0.40249
3- LU Airborne Particle Abrasion Non-Aged .891 25 0.01198*
4- LU Airborne Particle Abrasion Aged .954 25 0.31117
5- LU Silane Non-Aged .958 25 0.37427
6- LU Silane Aged .838 25 0.00106*
7- LU Adhesive Non-Aged .946 25 0.20847
8- LU Adhesive Aged .940 24 0.16501
9- LU Airborne Particle Abrasion and Silane Non-Aged .935 25 0.11179
10- LU Airborne Particle Abrasion & Silane Aged .977 25 0.82797
11- LU silane & Adhesive Non-Aged .960 25 0.40673
12- LU silane & Adhesive Aged .960 24 0.43507
13- LU Airborne Particle Abrasion & Adhesive Non-Aged .979 25 0.86994
14- LU Airborne Particle Abrasion & Adhesive Aged .979 25 0.85562
15- LU Airborne Particle Abrasion & Silane & Adhesive Non-Aged .965 25 0.53201
16- LU Airborne Particle Abrasion & Silane & Adhesive Aged .969 25 0.61556
VarseoSmile Crown Plus
17- VS Control Non-Aged .894 25 0.01374*
18- VS Control Aged .955 25 0.32888
19- VS Airborne Particle Abrasion Non-Aged .967 25 0.56680
20- VS Airborne Particle Abrasion Aged .883 25 0.00781*
21- VS Silane Non-Aged .855 25 0.00223*
22- VS Silane Aged .676 25 0.00000*
23- VS Adhesive Non-Aged .958 25 0.37382
24- VS Adhesive Aged .738 25 0.00002*
25- VS Airborne Particle Abrasion & Silane Non-Aged .951 25 0.26861
26- VS Airborne Particle Abrasion & Silane Aged .987 25 0.97771
27- VS Silane & Adhesive Non-Aged .862 25 0.00296*
28- VS Silane & Adhesive Aged .775 25 0.00009*
29- VS Airborne Particle Abrasion & Adhesive Non-Aged .919 25 0.04986*
30- VS Airborne Particle Abrasion & Adhesive Aged .947 25 0.21206
31- VS Airborne Particle Abrasion & Silane & Adhesive Non-Aged .935 25 0.11046
32- VS Airborne Particle Abrasion & Silane & Adhesive Aged .990 25 0.99467
Ceramic crown
33- CC Control Non-Aged .948 25 0.22596
34- CC Control Aged .962 25 0.45309
35- CC Airborne Particle Abrasion Non-Aged .955 25 0.32792
36- CC Airborne Particle Abrasion Aged .897 25 0.01599*
37- CC Silane Non-Aged .915 25 0.03944*
38- CC Silane Aged .954 25 0.31385
39- CC Adhesive Non-Aged .967 25 0.56920
40- CC Adhesive Aged .977 25 0.81166
41- CC Airborne Particle Abrasion and Silane Non-Aged .937 25 0.12507
42- CC Airborne Particle Abrasion & Silane Aged .968 25 0.59541
43- CC Silane & Adhesive Non-Aged .955 25 0.32814
44- CC Silane & Adhesive Aged .967 25 0.57999
53
45- CC Airborne Particle Abrasion & Adhesive Non-Aged .956 25 0.33665
46- CC Airborne Particle Abrasion & Adhesive Aged .951 25 0.25847
47- CC Airborne Particle Abrasion & Silane & Adhesive Non-Aged .953 25 0.29681
48- CC Airborne Particle Abrasion & Silane & Adhesive Aged .975 25 0.78343
*.Not normally distributed groups. (p=<0.05)
Levene’s test was used to evaluate the homogeneity of the data and it showed that the variances
were not homogeneous (p<0.001) (Table 4).
Parametric tests such as analysis of variance (ANOVA) have four requirements, including equal
sample size, independent variable, normal distribution, and homogeneity of variance. The first
two (equal sample size and independent variable) were met. However, parametric test such as
Generalized Linear Mixed Model (GLMM) measured ANOVA was applied. Because we only
have 12 groups that were not normally distributed reveal that the deviation is relatively slight.
The analysis of variance (ANOVA) is quite robust against violations of the normality and
heterogeneity assumptions.
(160-162) Also, the ANOVA measured allows the analysis of the main
variables (material, surface treatment, and aging ) and their interactions. (162)
Table 4: Levene’s Test (Equality of Variances)
Levene Statistic df1 df2 Sig.
σ Mpa
Based on Mean 5.324 47 1131 <.001
Based on Median 4.519 47 1131 <.001
Based on Median and with adjusted df 4.519 47 705.171 <.001
Based on trimmed mean 5.134 47 1131 <.001
54
3. Analysis of Variance (ANOVA):
A 3-way ANOVA was used to evaluate µTBS values with material and surface treatment as
between-subject factors and artificial aging within-subject, including their interactions. Followed
by 2-way ANOVA to evaluate µTBS values of each material separately and different surface
treatments, also µTBS value each material and the effect of artificial aging. This is followed by
1-way ANOVA to evaluate the significant difference between the Aged and non-Aged materials
in each surface treatment, more over the significant difference between each surface treatment in
each material before and after aging. Group-wise comparisons (post-hoc) were performed
separately for each group using the Bonferroni correction due to multiple comparisons (α=0.05).
The analysis of variance (ANOVA) of the µTBS has assessed the overall interaction between
Lava Ultimate (LU), VarseoSmile Crown Plus (VS), and Ceramic Crown. (CC) of different
surface treatments and aging (Table 5).
Table 5: Summary of Analysis of Variance (Material, Surface Treatment, and Aging) and Their Interactions
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 483592.358a 47 10290.25 100.75 0.00000
Intercept 1583667.76 1 1582908.31 15497.46 0.00000
Material 51747.92 2 25765.33 253.42 0.00000*
Surface Treatment 258618.44 7 36943.14 361.87 0.00000*
Aging 27459.22 1 27367.57 268.95 0.00000*
Material * Surface Treatment 82020.64 14 5855.27 57.38 0.00000*
Material * Aging 31848.08 2 15946.70 155.97 0.00000*
Surface Treatment * Aging 3012.60 7 426.11 4.22 0.00013*
Material * Surface treatment * Aging 10156.61 14 728.07 7.11 0.00000*
Error 115472.03 1131 102.14
Total 2317078.93 1179
Corrected Total 599064.39 1178
*p< 0.05 significant
a R Squared = .807 (Adjusted R Squared = .799)
Table 5 presents the ANOVA between (material, surface treatment, and aging) and their
interactions. All three main factor and their interactions were highly statistically significant
(p<0.05). Further analysis was performed based on the main factors Material, Surface Treatment,
and Aging.
55
3.1.Materials:
3.1.1. Overall:
The µTBS data showed that Ceramic Crown had the highest values, followed by Lava Ultimate,
and lastly VarseoSmile Crown Plus according to the estimated marginal means based on the
materials tested regardless of the aging and the surface treatment. (CC>LU>VS). (Table 6)
Table 6: Estimated Marginal Means (Material)
Material Mean Std. Error
95% Confidence Interval
Lower
Bound
Upper
Bound
Lava Ultimate 40.36 0.55 39.27 41.44
VarseoSmile Crown Plus 28.42 0.51 27.43 29.41
Ceramic Crown 43.84 0.51 42.85 44.83
The group-wise comparisons between the tested materials presented that all the materials were
significantly different (p<0.05) from each other (Table 7 and Figure 25)
Figure 25: Mean µTBS of Materials
Table 7: Group-wise Comparisons (Material)
(I) Materials (J) Materials
Mean
Difference
(I-J)
Std. Error P Valueb
95% Confidence
Interval for Difference.
b
Lower
Bound
Upper
Bound
Lava Ultimate VarseoSmile Crown Plus 11.92 0.75 0.00000* 10.12 13.72
Lava Ultimate Ceramic Crown -3.48 0.75 0.00001* -5.28 -1.69
VarseoSmile Crown Plus Ceramic Crown -15.40 0.72 0.00000* -17.12 -13.69
28.42
40.36
43.84
0
10
20
30
40
50
60
70
80
90
VarseoSmile Crown Plus LAVA Ultimate Ceramic Crown
MPa
56
3.1.2. One-Way ANOVA according to different surface treatments:
3.1.2.1. Control
Control Non-Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 8, Table 9)There was a statistically significant difference (p<0.001) between
different materials in (C.NA). The highest µTBS in control non-aged was observed in the
Ceramic crown.
Table 8: Analysis of Variance of Control Non-Aged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 2653.352a 2 1326.676 29.784 <.001
Intercept 19979.923 1 19979.923 448.545 <.001
Materials 2653.352 2 1326.676 29.784 <.001
Error 3207.157 72 44.544
Total 25840.432 75
Corrected Total 5860.509 74
Table 9: Estimated Marginal Means (Material) in control Non-Aged
Group-wise comparisons were performed for different materials when treated as control NonAged (Table 10) using the Bonferroni method due to multiple comparisons (α=0.05). The tested
materials (LU, VS) were not significantly different for each other. The (CC) was significantly
higher than other two tested materials in Control surface treatment before aging (p<0.05). (Table
10, and Figure 27)
Material Mean Std. Error 95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 11.831 1.335 9.17 14.492
VarseoSmile Crown Plus 12.408 1.335 9.747 15.069
Ceramic Crown 24.727 1.335 22.066 27.388
57
Table 10: Group-Wise Comparisons (Material) in Control Non-Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval for
Differenceb
Lower
Bound
Upper
Bound
Control Non- Aged
Lava
Ultimate
VarseoSmile
Crown Plus -0.577 1.888 1 -5.204 4.05
Ceramic
Crown -12.896* 1.888 <.001 -17.523 -8.269
VarseoSmile
Crown Plus
Ceramic
Crown -12.319* 1.888 <.001 -16.946 -7.692
11.831 12.408
24.727
0
10
20
30
40
50
60
70
80
90
LAVA Ultimate VarseoSmile Crown Plus Ceramic Crown
MPa
Not statistically significant
Figure 26: Mean µTBS of Materials in Control Non-Aged
58
Control Aged:
One-way ANOVA was used to evaluate the significance of µTBS values between the different
materials (Table 11,Table 12). There was a statistically significant difference (p<0.001) between
different materials in (C.A). The highest µTBS in control aged was observed in the Ceramic
Crown.
Table 11: Analysis of Variance of Control Aged Surface Treatment (Materials)
Table 12: Estimated Marginal Means (Material)in control Aged
Group-wise comparisons were performed for different materials when treated as control aged
(Table 13) using the Bonferroni method due to multiple comparisons (α=0.05). The tested
materials (VS, LU,CC) were statistically significantly different from each other when the surface
treatment (C.A) was utilized(p<0.05).( Figure 27)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 1340.185a 2 670.093 19.707 <.001
Intercept 2964.490 1 2964.490 87.183 <.001
Materials 1340.185 2 670.093 19.707 <.001
Error 1802.172 53 34.003
Total 10609.433 56
Corrected Total 3142.357 55
Material Mean Std. Error 95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 1.547 2.381 -3.228 6.322
VarseoSmile Crown Plus 9.092 1.166 6.753 11.431
Ceramic Crown 16.403 1.166 14.064 18.742
59
Table 13: Group-Wise Comparisons (Material) in Control Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval for
Difference b
Lower
Bound
Upper
Bound
Control Aged
Lava
Ultimate
VarseoSmile
Crown Plus -7.545* 2.651 0.019 -14.099 -0.991
Ceramic
Crown -14.856* 2.651 <.001 -21.41 -8.302
VarseoSmile
Crown Plus
Ceramic
Crown -7.311* 1.649 <.001 -11.388 -3.233
Figure 27: Mean µTBS of Materials in Control Aged
1.547
9.092
16.403
-10
0
10
20
30
40
50
60
70
80
90
LAVA Ultimate VarseoSmile Crown Plus Ceramic Crown
MPa
60
3.1.2.2. Airborne Particle Abrasion
Airborne particle Abrasion Non-Aged:
One-way ANOVA was used to evaluate the significance of µTBS values between the different
materials (Table 14, Table 15). There was a statistically significant difference (p<0.001) between
different materials in (P.NA). The highest µTBS in Airborne Particle Abrasion non-aged was
observed in the Lava Ultimate.
Table 14: Analysis of Variance of Airborne Particle Abrasion Non-aged Surface Treatment (Materials)
Table 15: Estimated Marginal Means (Material)in Airborne Particle Abrasion Non-Aged
Group-wise comparisons were performed for different materials when treated with Airborne
Particle Abrasion Non- aged (Table 16) using the Bonferroni method due to multiple
comparisons (α=0.05). The tested materials (VS, CC) were not statistically significantly
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 21691.621a 2 10845.811 66.168 <.001
Intercept 243399.198 1 243399.198 1484.920 <.001
Materials 21691.621 2 10845.811 66.168 <.001
Error 11801.805 72 163.914
Total 276892.625 75
Corrected Total 33493.427 74
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 80.557 2.561 75.453 85.662
VarseoSmile Crown Plus 41.113 2.561 36.008 46.217
Ceramic Crown 49.233 2.561 44.129 54.338
61
different from each other, but they were statistically significantly different from (LU) when the
surface treatment (P.NA) was utilized (p<0.05).( Figure 27)
Table 16: Group-wise Comparisons (Material)in Airborne Particle Abrasion Non- Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval for
Difference b
Lower
Bound
Upper
Bound
Airborne
Particle
Abrasion
Non- Aged
Lava
Ultimate
VarseoSmile
Crown Plus 39.444* 3.621 <.001 30.568 48.321
Ceramic
Crown 31.324* 3.621 <.001 22.448 40.2
VarseoSmile
Crown Plus
Ceramic
Crown -8.12 3.621 0.084 -16.997 0.756
Figure 28: Mean µTBS of materials in Airborne Particle Abrasion Non- Aged
41.113
49.233
80.557
0
10
20
30
40
50
60
70
80
90
VarseoSmile Crown Plus Ceramic Crown Lava Ultimate
Mean MPa
Not Statistically significant
62
Airborne particle Abrasion Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 17,Table 18). There was a statistically significant difference (p<0.05) between
different materials in (P. A). The highest µTBS in Airborne Particle Abrasion aged was observed
in the Lava Ultimate.
Table 17: Analysis of Variance of Airborne Particle Abrasion Aged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 1001.151a 2 500.576 3.560 .034
Intercept 138830.704 1 138830.704 987.313 <.001
Materials 1001.151 2 500.576 3.560 .034
Error 10124.255 72 140.615
Total 149956.109 75
Corrected Total 11125.406 74
Table 18: Estimated Marginal Means (Material) in Airborne Particle Abrasion Aged
Group-wise comparisons were performed for different materials when treated with airborne
Particle Abrasion aged (Table 19) using the Bonferroni method due to multiple comparisons (α
=0.05). The tested materials (VS, CC,LU) were not statistically significantly different from each
other when the surface treatment (P.A) was utilized (p>0.05).(Figure 29 )
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 48.185 2.372 43.457 52.913
VarseoSmile Crown Plus 40.664 2.372 35.937 45.392
Ceramic Crown 40.223 2.372 35.495 44.951
63
Table 19: Group-wise Comparisons (Material) in Airborne Particle Abrasion Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval for
Differenceb
Lower
Bound
Upper
Bound
Airborne
Particle
Abrasion
Non- Aged
Lava
Ultimate
VarseoSmile
Crown Plus 7.52 3.354 0.084 -0.701 15.742
Ceramic
Crown 7.962 3.354 0.061 -0.26 16.183
VarseoSmile
Crown Plus
Ceramic
Crown 0.441 3.354 1 -7.78 8.662
40.223 40.664
48.185
0
10
20
30
40
50
60
70
80
90
Ceramic Crown VarseoSmile Crown Plus Lava Ultimate
MPa
Not Statistically significant
Figure 29: Mean µTBS of materials in Airborne Particle Abrasion Aged
64
3.1.2.3. Silane
Silane Non-Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 20, Table 21). There was statistically significant difference (p<0.001) between
different materials in (S.NA). The highest µTBS in Silane Non- aged was observed in the
Ceramic Crown.
Table 20: Analysis of Variance of Silane Non- Aged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 16043.411a 2 8021.705 64.866 <.001
Intercept 76674.611 1 76674.611 620.011 <.001
Materials 16043.411 2 8021.705 64.866 <.001
Error 8903.985 72 123.666
Total 101622.007 75
Corrected Total 24947.396 74
Table 21: Estimated Marginal Means (Material) in Silane Non- Aged
Group-wise comparisons were performed for different materials when treated with Silane Nonaged (Table 22)using the Bonferroni method due to multiple comparisons (α=0.05). The tested
materials (LU, CC) were not statistically significantly different from each other ,but they were
statistically significantly different from (VS) when the surface treatment (S.NA) was utilized
(p<0.05). (Figure 30)
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 41.104 2.224 36.670 45.537
VarseoSmile Crown Plus 11.336 2.224 6.902 15.769
Ceramic Crown 43.482 2.224 39.049 47.916
65
Table 22: Group-wise Comparisons (Material) in Silane Non-Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval for
Differenceb
Lower
Bound
Upper
Bound
Silane Non- Aged
Lava
Ultimate
VarseoSmile
Crown Plus 29.768* 3.145 <.001 22.058 37.478
Ceramic
Crown -2.379 3.145 1 -10.089 5.331
VarseoSmile
Crown Plus
Ceramic
Crown -32.147* 3.145 <.001 -39.857 -24.437
Figure 30: Mean µTBS of Materials in Silane Non-Aged
11.336
41.104 43.482
0
10
20
30
40
50
60
70
80
90
VarseoSmile Crown Plus Lava Ultimate Ceramic Crown
MPa
Not Statistically significant
66
Silane Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 23,Table 24). There was a statistically significant difference (p<0.001) between
different materials in (S.A). The highest µTBS in Silane aged was observed in the Ceramic
Crown.
Table 23: Analysis of Variance of Silane Aged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 8768.092a 2 4384.046 41.327 <.001
Intercept 38565.073 1 38565.073 363.538 <.001
Materials 8768.092 2 4384.046 41.327 <.001
Error 7637.953 72 106.083
Total 54971.119 75
Corrected Total 16406.046 74
Table 24: Estimated Marginal Means (Material)in Silane Aged
Group-wise comparisons were performed for different materials when treated with Silane aged
(Table 25)using the Bonferroni method due to multiple comparisons (α=0.05). The tested
materials (LU,VS) were not statistically significantly different from each other, but They were
statistically significantly different from (CC) when the surface treatment (S.A) was utilized
(p<0.05).(Figure 31)
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 17.465 2.060 13.359 21.572
VarseoSmile Crown Plus 12.832 2.060 8.725 16.938
Ceramic Crown 37.731 2.060 33.625 41.838
67
Table 25:Group-wise Comparisons (Material) in Silane Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval for
Differenceb
Lower
Bound
Upper
Bound
Silane Aged
Lava
Ultimate
VarseoSmile
Crown Plus 4.634 2.913 0.348 -2.507 11.774
Ceramic
Crown -20.266* 2.913 <.001 -27.407 -13.125
VarseoSmile
Crown Plus
Ceramic
Crown -24.900* 2.913 <.001 -32.04 -17.759
Figure 31: Mean µTBS of Materials in Silane Aged
12.832
17.465
37.731
0
10
20
30
40
50
60
70
80
90
VarseoSmile Crown Plus Lava Ultimate Ceramic Crown
MPa
Not Statistically significant
68
3.1.2.4. Adhesive
Adhesive Non-Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 26, Table 27)There was statistically significant difference (p<0.001) between
different materials in (A.NA). The highest µTBS in Adhesive Non- aged was observed in
Ceramic Crown.
Table 26: Analysis of Variance of Adhesive Non-Aged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 9869.577a 2 4934.788 53.330 <.001
Intercept 60100.715 1 60100.715 649.508 <.001
Materials 9869.577 2 4934.788 53.330 <.001
Error 6662.355 72 92.533
Total 76632.647 75
Corrected Total 16531.932 74
Table 27: Estimated Marginal Means (Material) in Adhesive Non- Aged
Group-wise comparisons were performed for different materials when treated with Adhesive
Non- aged (Table 28)using the Bonferroni method due to multiple comparisons (α=0.05). The
Three tested materials (LU, VS,CC) were Statistically significantly different from each other
when (A.NA) surface treatment was utilized (p<0.05).(Figure 32)
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 18.460 1.924 14.624 22.295
VarseoSmile Crown Plus 22.068 1.924 18.232 25.903
Ceramic Crown 44.397 1.924 40.562 48.232
69
Table 28: Group-wise Comparisons (Material) in Adhesive Non- Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval for
Differenceb
Lower
Bound
Upper
Bound
Adhesive Non-Aged
Lava
Ultimate
VarseoSmile
Crown Plus -3.608 2.721 0.567 -10.277 3.061
Ceramic
Crown -25.937* 2.721 <.001 -32.606 -19.268
VarseoSmile
Crown Plus
Ceramic
Crown -22.329* 2.721 <.001 -28.998 -15.66
Figure 32: Mean µMTS of Materials in Adhesive Non- Aged
18.46
22.068
44.397
0
10
20
30
40
50
60
70
80
90
Lava Ultimate VarseoSmile Crown Plus Ceramic Crown
MPa
70
Adhesive Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 29, Table 30)There was statistically significant difference (p<0.001) between
different materials in (A.A). The highest µTBS in Adhesive aged was observed in the CC.
Table 29: Analysis of Variance of Adhesive Aged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 14232.506a 2 7116.253 98.151 <.001
Intercept 27040.051 1 27040.051 372.952 <.001
Materials 14232.506 2 7116.253 98.151 <.001
Error 5220.198 72 72.503
Total 46492.756 75
Corrected Total 19452.704 74
Table 30: Estimated Marginal Means (Material) in Adhesive Aged
Group-wise comparisons were performed for different materials when treated with Adhesive
aged (Table 30)using the Bonferroni method due to multiple comparisons (α=0.05). The Three
tested materials (LU, VS, CC) were statistically significantly different from each other when
(A.A) the surface treatment was utilized (p<0.05).(Figure 33)
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 2.939 1.703 -.456 6.334
VarseoSmile Crown Plus 17.448 1.703 14.053 20.843
Ceramic Crown 36.576 1.703 33.182 39.971
71
Table 31: Group-wise Comparisons (Material) in Adhesive Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval for
Differenceb
Lower
Bound
Upper
Bound
Adhesive Aged
Lava
Ultimate
VarseoSmile
Crown Plus -14.509* 2.408 <.001 -20.413 -8.606
Ceramic
Crown -33.638* 2.408 <.001 -39.541 -27.734
VarseoSmile
Crown Plus
Ceramic
Crown -19.128* 2.408 <.001 -25.032 -13.225
Figure 33: Mean µTBS Of Materials in Adhesive Aged
2.939
17.448
36.576
0
10
20
30
40
50
60
70
80
90
Lava Ultimate VarseoSmile Crown Plus Ceramic Crown
MPa
72
3.1.2.5. Airborne Particle Abrasion +Silane
Airborne Particle Abrasion +Silane Non-Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 32,Table 33)There was statistically significant difference (p<0.001) between
different materials in (PS.NA). The highest µTBS in Airborne Particle Abrasion+Silane Nonaged was observed in the Lava Ultimate.
Table 32: Analysis of Variance of Airborne Particle Abrasion+ Silane Non- Aged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 24580.149a 2 12290.074 131.952 <.001
Intercept 237552.252 1 237552.252 2550.482 <.001
Materials 24580.149 2 12290.074 131.952 <.001
Error 6706.090 72 93.140
Total 268838.491 75
Corrected Total 31286.239 74
Table 33: Estimated Marginal Means (Material) in of Airborne Particle Abrasion+Silane Non- Aged
Group-wise comparisons were performed for different materials when treated with Airborne
Particle Abrasion+Silane Non- aged (Table 34)using the Bonferroni method due to multiple
comparisons (α=0.05). The Three tested materials (LU,VS,CC) were statistically significantly
different from each with surface treatment (PS.NA)was utilized (p<0.05).(Figure 34)
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 81.170 1.930 77.322 85.017
VarseoSmile Crown Plus 38.642 1.930 34.794 42.490
Ceramic Crown 49.026 1.930 45.179 52.874
73
Table 34: Group-wise Comparisons (Material)in Airborne Particle Abrasion+Silane Non- Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std.
Error Sig.b
95% Confidence Interval
for Difference b
Lower
Bound
Upper
Bound
Airborne
Particle
Abrasion
+ Silane
NonAged
Lava
Ultimate
VarseoSmile
Crown Plus 42.528* 2.73 <.001 35.837 49.219
Ceramic
Crown 32.143* 2.73 <.001 25.452 38.834
VarseoSmile
Crown Plus
Ceramic
Crown -10.384* 2.73 <.001 -17.075 -3.693
Figure 34: Mean µTBS of Materials n Airborne Particle Abrasion+Silane Non- Aged
38.642
49.026
81.17
0
10
20
30
40
50
60
70
80
90
VarseoSmile Crown Plus Ceramic Crown Lava Ultimate
Mean MPa
74
Airborne Particle Abrasion +Silane Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 35, Table 36)There was statistically significant difference (p<0.001) between
different materials in (PS.A). The highest µTBS in Airborne Particle Abrasion+Silane aged was
observed in the Ceramic Crown.
Table 35: Analysis of Variance of Airborne Particle Abrasion+Silane Aged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 3346.083a 2 1673.042 14.288 <.001
Intercept 195216.806 1 195216.806 1667.234 <.001
Materials 3346.083 2 1673.042 14.288 <.001
Error 8430.499 72 117.090
Total 206993.388 75
Corrected Total 11776.582 74
Table 36: Estimated Marginal Means (Material)in of Airborne Particle Abrasion+Silane Aged
Group-wise comparisons were performed for different materials when treated with Airborne
Particle Abrasion+Silane aged (Table 37) using the Bonferroni method due to multiple
comparisons (α=0.05). The tested materials (LU, CC) were not statistically significantly
different from each other, but they were statistically significantly different from (VS) when
(PS.A) surface treatment was utilized (p<0.05).(Figure 35)
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 54.845 2.164 50.531 59.159
VarseoSmile Crown Plus 41.626 2.164 37.312 45.940
Ceramic Crown 56.585 2.164 52.271 60.899
75
Table 37: Group-wise Comparisons (Material)in Airborne Particle Abrasion+Silane Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval for
Differenceb
Lower
Bound
Upper
Bound
Airborne
Particle
Abrasion +
Silane
Aged
Lava
Ultimate
VarseoSmile
Crown Plus
13.219* 3.061 <.001 5.717 20.721
Ceramic
Crown -1.74 3.061 1 -9.242 5.762
VarseoSmile
Crown Plus
Ceramic
Crown -14.959* 3.061 <.001 -22.461 -7.457
Figure 35: Mean µTBS of materials in Airborne Particle Abrasion+Silane Aged
41.626
54.845 56.585
0
10
20
30
40
50
60
70
80
90
VarseoSmile Crown Plus Lava Ultimate Ceramic Crown
MPa
Not Statistically significant
76
3.1.2.6. Silane +Adhesive
Silane + Adhesive Non-Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 38, Table 39)There was statistically significant difference (p<0.001) between
different materials in (SA.NA). The highest µTBS in Silane +Adhesive Non-aged was observed
in the Ceramic Crown.
Table 38: Analysis of Variance of Silane + Adhesive Non-Aged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 11561.108a 2 5780.554 47.487 <.001
Intercept 66704.955 1 66704.955 547.977 <.001
Materials 11561.108 2 5780.554 47.487 <.001
Error 8764.523 72 121.729
Total 87030.586 75
Corrected Total 20325.632 74
Table 39:Estimated Marginal Means (Material) in of Silane + Adhesive Non- Aged
Group-wise comparisons were performed for different materials when treated with Silane
+Adhesive Non- aged (Table 40) using the Bonferroni method due to multiple comparisons (α
=0.05). The tested materials (LU, VS) were not statistically significantly different from each
other, but they were statistically significantly different form (CC) when the surface treatment
(SA.NA)was utilized (p<0.05).(Figure 36)
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 21.965 2.207 17.566 26.364
VarseoSmile Crown Plus 20.154 2.207 15.755 24.552
Ceramic Crown 47.350 2.207 42.951 51.749
77
Table 40: Group-wise Comparisons (Material) in Silane + Adhesive Non- Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval
for Differenceb
Lower
Bound
Upper
Bound
Silane +
Adhesive
NonAged
Lava Ultimate
VarseoSmile
Crown Plus
1.811 3.121 1 -5.838 9.46
Ceramic Crown -25.385* 3.121 <.001 -33.034 -17.736
VarseoSmile
Crown Plus
Ceramic Crown -27.196* 3.121 <.001 -34.846 -19.547
Figure 36: Mean µTBS of Materials in Silane + Adhesive Non- Aged
20.154 21.965
47.35
0
10
20
30
40
50
60
70
80
90
VarseoSmile Crown Plus Lava Ultimate Ceramic Crown
MPa
Not Statistically significant
78
Silane + Adhesive Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 41, Table 42). There was statistically significant difference (p<0.001) between
different materials in (SA.A). the highest µTBS in Silane +Adhesive aged was observed in the
Ceramic Crown.
Table 41: Analysis of Variance of Silane + Adhesive Aged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 17243.893a 2 8621.946 88.906 <.001
Intercept 39572.027 1 39572.027 408.052 <.001
Materials 17243.893 2 8621.946 88.906 <.001
Error 6982.403 72 96.978
Total 63798.323 75
Corrected Total 24226.296 74
Table 42: Estimated Marginal Means (Material) in of Silane + Adhesive Aged
Group-wise comparisons were performed for different materials when treated with Silane
+Adhesive aged (Table 43) using the Bonferroni method due to multiple comparisons (α=0.05).
The tested materials (LU, VS, CC) were Statistically significantly different from each other
When the surface treatment (SA.NA) was utilized (p<0.05).(Figure 37)
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 6.540 1.970 2.613 10.466
VarseoSmile Crown Plus 19.252 1.970 15.326 23.178
Ceramic Crown 43.119 1.970 39.193 47.045
79
Table 43: Group-wise Comparisons (Material) in Silane + Adhesive Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval
for Differenceb
Lower
Bound
Upper
Bound
Silane +
Adhesive Aged
Lava Ultimate
VarseoSmile
Crown Plus -12.712* 2.785 <.001 -19.54 -5.885
Ceramic Crown -36.579* 2.785 <.001 -43.407 -29.752
VarseoSmile
Crown Plus
Ceramic Crown -23.867* 2.785 <.001 -30.694 -17.039
Figure 37: Mean µTBS of Materials in Silane + Adhesive Aged
6.54
19.252
43.119
0
10
20
30
40
50
60
70
80
90
Lava Ultimate VarseoSmile Crown Plus Ceramic Crown
MPa
80
3.1.2.7. Airborne Particle Abrasion +Adhesive
Airborne Particle Abrasion +Adhesive Non-Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 44,Table 45)There was statistically significant difference (p<0.001) between
different materials in (PA.NA). The highest µTBS in Airborne Particle Abrasion +Adhesive
Non-aged was observed in the Lava Ultimate.
Table 44: Analysis of Variance of Airborne Particle Abrasion +Adhesive Non-Aged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 26569.107a 2 13284.554 103.230 <.001
Intercept 278447.054 1 278447.054 2163.719 <.001
Materials 26569.107 2 13284.554 103.230 <.001
Error 9265.614 72 128.689
Total 314281.775 75
Corrected Total 35834.721 74
Table 45: Estimated Marginal Means (Material) in of Airborne Particle Abrasion +Adhesive Non-Aged
Group-wise comparisons were performed for different materials when treated with Airborne
Particle Abrasion +Adhesive Non-aged (Table 46) using the Bonferroni method due to multiple
comparisons (α=0.05). The tested materials (LU, VS, CC) were statistically significantly
different from each other when the surface treatment (PA. A) was utilized (p<0.05). ( Figure 38)
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 86.033 2.269 81.510 90.556
VarseoSmile Crown Plus 40.712 2.269 36.189 45.235
Ceramic Crown 56.049 2.269 51.526 60.572
81
Table 46: Group-wise Comparisons (Material) in Airborne Particle Abrasion +Adhesive Non-Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval for
Differenceb
Lower
Bound
Upper
Bound
Airborne
Particle
Abrasion +
Adhesive
Non-Aged
Lava
Ultimate
VarseoSmile
Crown Plus
45.321* 3.209 <.001 37.456 53.186
Ceramic
Crown
29.984* 3.209 <.001 22.119 37.849
VarseoSmile
Crown Plus
Ceramic
Crown -15.337* 3.209 <.001 -23.202 -7.472
Figure 38: Mean µTBS of Materials Airborne Particle Abrasion +Adhesive Non-Aged
40.712
56.049
86.033
0
10
20
30
40
50
60
70
80
90
VarseoSmile Crown Plus Ceramic Crown Lava Ultimate
MPa
82
Airborne Particle Abrasion +Adhesive Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 47,Table 48)There was statistically significant difference (p<0.001) between
different materials in (PA.NA). The highest µTBS in Airborne Particle Abrasion +Adhesive aged
was observed in Ceramic Crown.
Table 47: Analysis of Variance of Airborne Particle Abrasion +Adhesive Aged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 3353.033a 2 1676.516 14.929 <.001
Intercept 168090.138 1 168090.138 1496.842 <.001
Materials 3353.033 2 1676.516 14.929 <.001
Error 8085.349 72 112.297
Total 179528.520 75
Corrected Total 11438.381 74
Table 48: Estimated Marginal Means (Material) in of Airborne Particle Abrasion +Adhesive Aged
Group-wise comparisons were performed for different materials when treated with Airborne
Particle Abrasion +Adhesive aged (Table 49) using the Bonferroni method due to multiple
comparisons (α=0.05). The tested materials (LU, VS) were Not Statistically significantly
different from each other ,but the (CC) was statistically significantly different from them when
the surface treatment (PA. A) was utilized (p<0.05). ( Figure 39)
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 41.997 2.119 37.772 46.222
VarseoSmile Crown Plus 43.258 2.119 39.033 47.483
Ceramic Crown 56.769 2.119 52.544 60.994
83
Table 49: Group-wise Comparisons (Material) in Airborne Particle Abrasion +Adhesive Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval for
Differenceb
Lower
Bound
Upper
Bound
Airborne
Particle
Abrasion +
Adhesive
Aged
Lava
Ultimate
VarseoSmile
Crown Plus -1.26 2.997 1 -8.607 6.087
Ceramic
Crown -14.772* 2.997 <.001 -22.119 -7.425
VarseoSmile
Crown Plus
Ceramic
Crown -13.512* 2.997 <.001 -20.859 -6.165
Figure 39: Mean µTBS of materials Airborne Particle Abrasion +Adhesive Aged
41.997 43.258
56.769
0
10
20
30
40
50
60
70
80
90
Lava Ultimate VarseoSmile Crown Plus Ceramic Crown
MPa
Not Statistically significant
84
3.1.2.8. Airborne Particle Abrasion +Silane +Adhesive
Airborne Particle Abrasion +Silane +Adhesive Non-Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 50,Table 51)There was statistically significant difference (p<0.001) between
different materials in (PSA.NA). The highest µTBS in Airborne Particle Abrasion +Silane
+Adhesive Non-aged was observed in the Lava Ultimate.
Table 50: Analysis of Variance of Airborne Particle Abrasion +Silane +Adhesive Non-Aged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 22288.482a 2 11144.241 124.658 <.001
Intercept 262132.168 1 262132.168 2932.180 <.001
Materials 22288.482 2 11144.241 124.658 <.001
Error 6436.684 72 89.398
Total 290857.334 75
Corrected Total 28725.166 74
Table 51: Estimated Marginal Means (Material) in of Airborne Particle Abrasion +Silane +Adhesive Non-Aged
Group-wise comparisons were performed for different materials when treated with Airborne
Particle Abrasion +Adhesive aged (Table 52) using the Bonferroni method due to multiple
comparisons (α=0.05). The tested materials (LU, VS, CC) were statistically significantly
different from each other with the surface treatment (PSA.NA) was utilized (p<0.05).(Figure 40)
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 82.695 1.891 78.926 86.465
VarseoSmile Crown Plus 41.955 1.891 38.186 45.725
Ceramic Crown 52.708 1.891 48.938 56.477
85
Table 52: Group-wise Comparisons (Material) in Airborne Particle Abrasion +Silane +Adhesive Non-Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval for
Differenceb
Lower
Bound
Upper
Bound
Airborne
Particle
Abrasion +
Silane
+Adhesive
Non-Aged
Lava
Ultimate
VarseoSmile
Crown Plus
40.740* 2.674 <.001 34.185 47.295
Ceramic
Crown
29.988* 2.674 <.001 23.432 36.543
VarseoSmile
Crown Plus
Ceramic
Crown -10.752* 2.674 <.001 -17.308 -4.197
Figure 40: Mean µTBS of materials Airborne Particle Abrasion +Silane +Adhesive Non-Aged
41.955
52.708
82.695
0
10
20
30
40
50
60
70
80
90
VarseoSmile Crown Plus Ceramic Crown Lava Ultimate
MPa
86
Airborne Particle Abrasion +Silane +Adhesive Aged:
One-way ANOVA was used to evaluate the significance of µTBs values between the different
materials (Table 53,Table 54)There was statistically significant difference (p<0.05) between
different materials in (PSA. A). The highest µTBS in Airborne Particle Abrasion +Silane
+Adhesive aged was observed in the Lava Ultimate.
Table 53: Analysis of Variance of Airborne Particle Abrasion +Silane +AdhesiveAged Surface Treatment (Materials)
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 488.148a 2 244.074 3.199 .047
Intercept 156751.021 1 156751.021 2054.173 <.001
Materials 488.148 2 244.074 3.199 .047
Error 5494.218 72 76.309
Total 162733.386 75
Corrected Total 5982.365 74
Table 54: Estimated Marginal Means (Material) in of Airborne Particle Abrasion +Silane +Adhesive Aged
Group-wise comparisons were performed for different materials when treated with Airborne
Particle Abrasion +Adhesive aged (Table 55) using the Bonferroni method due to multiple
comparisons (α=0.05). The tested materials (LU, CC) were not statistically significantly
different from each other, but they were statistically significantly different from (VS) with the
surface treatment (PSA.A) was utilized (p<0.05).(Figure 41)
Material Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate 47.961 1.747 44.478 51.444
VarseoSmile Crown Plus 42.148 1.747 38.665 45.631
Ceramic Crown 47.041 1.747 43.558 50.524
87
Table 55: Group-wise Comparisons (Material) in Airborne Particle Abrasion Abrasion +Silane +Adhesive Aged
Surface
Treatment Aging Materials
Mean
Difference
(I-J)
Std. Error Sig.b
95% Confidence Interval for
Differenceb
Lower
Bound
Upper
Bound
Airborne
Particle
Abrasion +
Silane
+Adhesive
Aged
Lava
Ultimate
VarseoSmile
Crown Plus
5.813 2.471 0.064 -0.244 11.869
Ceramic
Crown
0.92 2.471 1 -5.137 6.976
VarseoSmile
Crown Plus
Ceramic
Crown -4.893 2.471 0.154 -10.95 1.163
Figure 41: Mean µTBS of materials Airborne Particle Abrasion +Silane +Adhesive Aged
42.148
47.041 47.961
0
10
20
30
40
50
60
70
80
90
VarseoSmile Crown Plus Ceramic Crown Lava Ultimate
MPa
Not statistically significant
88
3.2.Surface Treatment:
Overall:
The µTBS data showed that the surface treated with (PA) had the highest µTBs values and the
lowest was observed in C according to the estimated marginal means based on the surface
treatment tested. The descending order of µTBS according to the surface treatment was
PA>PS>PSA>P>S>SA>A>C (Table 56).
Table 56: Estimated Marginal Means (Surface treatment)
Surface Treatment Mean
Std.
Error
95% Confidence Interval
Lower Bound Upper Bound
Control (C) 12.67 1.02 10.67 14.67
Airborne Particle Abrasion( P) 50.00 0.83 48.38 51.62
Silane (S) 27.32 0.83 25.71 28.94
Adhesive(A) 23.67 0.83 22.04 25.29
Airborne Particle Abrasion + Silane (PS) 53.65 0.83 52.03 55.27
Silane + Adhesive (SA) 26.44 0.83 24.82 28.07
Airborne Particle Abrasion + Adhesive (PA) 54.19 0.83 52.56 55.81
Airborne Particle Abrasion + Silane + Adhesive (PSA) 52.42 0.83 50.80 54.04
The group-wise comparisons between the tested surface treatments (C, P, S, A, PS, SA, PA, and
PSA) presented that the surface treatment of different materials aged and non-aged all of them
were statistically significantly different from the control group (p<0.05). While (S, A, SA)were
not statistically significant from each other. (P, PA, PS, PSA) are not statistically significant from
each other. However, the (S,A,SA) were statistically significant from (P, PA, PS, PSA) (p<0.05).(
Table 57,and Figure 42)
89
Table 57: Group-wise Comparisons (Surface Treatments)
(I) Surface Treatment (J) Surface Treatment
Mean
Difference (IJ)
Std.
Error
P Value
95% Confidence
Interval for
Difference
Lower
Bound
Upper
Bound
Control
Airborne Particle Abrasion -37.33 1.31 0.00000* -41.44 -33.22
Silane -14.66 1.31 0.00000* -18.77 -10.55
Adhesive -11.00 1.31 0.00000* -15.11 -6.89
Airborne Particle Abrasion + Silane -40.98 1.31 0.00000* -45.09 -36.87
Silane + Adhesive -13.77 1.31 0.00000* -17.89 -9.66
Airborne Particle Abrasion + Adhesive -41.52 1.31 0.00000* -45.63 -37.40
Airborne Particle Abrasion + Silane + Adhesive -39.75 1.31 0.00000* -43.86 -35.64
Airborne Particle
Abrasion
Silane 22.67 1.17 0.00000* 19.02 26.33
Adhesive 26.33 1.17 0.00000* 22.67 29.99
Airborne Particle Abrasion + Silane -3.65 1.17 0.05015 -7.31 0.00
Silane + Adhesive 23.55 1.17 0.00000* 19.89 27.21
Airborne Particle Abrasion + Adhesive -4.19 1.17 0.00986* -7.85 -0.53
Airborne Particle Abrasion + Silane + Adhesive -2.42 1.17 1.00000 -6.08 1.23
Silane
Adhesive 3.66 1.17 0.05054* 0.00 7.32
Airborne Particle Abrasion + Silane -26.32 1.17 0.00000* -29.98 -22.67
Silane + Adhesive 0.88 1.17 1.00000 -2.78 4.54
Airborne Particle Abrasion + Adhesive -26.86 1.17 0.00000* -30.52 -23.20
Airborne Particle Abrasion + Silane + Adhesive -25.09 1.17 0.00000* -28.75 -21.44
Adhesive
Airborne Particle Abrasion + Silane -29.98 1.17 0.00000* -33.64 -26.32
Silane + Adhesive -2.77 1.17 0.50525 -6.44 0.89
Airborne Particle Abrasion + Adhesive -30.52 1.17 0.00000* -34.18 -26.85
Airborne Particle Abrasion + Silane + Adhesive -28.75 1.17 0.00000* -32.41 -25.09
Airborne Particle
Abrasion + Silane
Silane + Adhesive 27.21 1.17 0.00000* 23.55 30.87
Airborne Particle Abrasion + Adhesive -0.54 1.17 1.00000 -4.20 3.12
Airborne Particle Abrasion + Silane + Adhesive 1.23 1.17 1.00000 -2.42 4.88
Silane + Adhesive
Airborne Particle Abrasion + Adhesive -27.75 1.17 0.00000* -31.41 -24.08
Airborne Particle Abrasion + Silane + Adhesive -25.98 1.17 0.00000* -29.64 -22.32
Airborne Particle
Abrasion + Adhesive
Airborne Particle Abrasion + Silane + Adhesive 1.77 1.17 1.00000 -1.89 5.43
90
Figure 42: Mean µTBS for Different Surface Treatment
3.2.1. Lava Ultimate:
The mean µTBS and standard deviation of Lava Ultimate for all different aged and non-aged
surface treatments are presented in (Table 58 and Figure 43). The highest overall mean µTBS
value in Lava Ultimate was observed for the group Airborne Particle Abrasion + Adhesive
before aging (LU PA.NA; 86.033±16.89MPa), while the lowest was observed in Control after
aging (LU C.A; 1.547±1.03Mpa).
12.67
23.67
26.44 27.32
50.00
52.42 53.65 54.19
0
10
20
30
40
50
60
70
80
90
Control Adhesive Silane +
Adhesive
Silane Airborne
Particle
Abrasion
Airborne
particle
Abrasion +
Silane +
Adhesive
Airborne
particle
Abrasion +
Silane
Airborne
particle
Abrasion +
Adhesive
MPa
Not statistically significant
Not statistically significant
91
Figure 43: Micro Tensile Bond Strength of Lava Ultimate
Non-Aged: The µTBS value was highest when treated with Airborne Particle Abrasion +
Adhesive (PA) (LU PA .NA; 86.033±16.89 Mpa), and lowest was observed in control (LU
C.NA; 11.831±3.78 Mpa). (PA>PSA>PS>P>S>SA>A>C).
Aged: The µTBS value was highest when treated with Airborne Particle Abrasion + Silane (PS)
(LU PS. A; 54.845±13.99 MPa). While the lowest µTBS was in control (LU C.A;
1.547±1.03MPa). (PS>P>PSA>PA>S>SA>A>C).
11.831
80.557
41.104
18.46
81.17
21.965
86.033 82.695
1.547
48.185
17.465
3.061
54.845
6.81
41.997
47.961
0
10
20
30
40
50
60
70
80
90
Control Airborne
Particle
Abrasion
Silane Adhesive Airborne
particle
Abrasion +
Silane
Silane +
Adhesive
Airborne
particle
Abrasion +
Adhesive
Airborne
particle
Abrasion +
Silane +
Adhesive
σ MPa
Surface Treatments
Non-Aged Aged
Table 58: Mean Micro Tensile Bond Strength and Standard Deviation of Lava Ultimate
Surface Treatment
Mean NonAged
σ SD NonAged
Mean Aged σ SD Aged
Lava Ultimate
Control 11.831 ± 3.78 1.547 ± 1.03
Airborne Particle Abrasion 80.557 ± 18.87 48.185 ± 13.34
Silane 41.104 ± 16.10 17.465 ± 8.86
Adhesive 18.460 ± 5.65 3.061 ± 1.89
Airborne Particle Abrasion + Silane 81.170 ± 12.77 54.845 ± 13.99
Silane + Adhesive 21.965 ± 8.16 6.810 ± 3.12
Airborne Particle Abrasion + Adhesive 86.033 ± 16.89 41.997 ± 14.17
Airborne Particle Abrasion + Silane + Adhesive 82.695 ± 10.78 47.961 ± 12.19
92
3.2.1.1. 2-Way ANOVA
Two-way ANOVA was used to evaluate the significance of µTBs values between the different
surface treatments (Table 59,Table 60). There was a statistically significant difference (p=0.000)
between different surface treatments in (LU) before and after aging
Table 59: Analysis of Variance of Lava Ultimate (Surface Treatment, and Aging) and their interactions
Source Type III Sum of Squares df Mean
Square
F P Value
Corrected Model 308919.11 15 20594.61 147.77 0.00000
Intercept 541439.24 1 541439.24 3885.01 0.00000
Surface Treatment 227009.19 7 32429.88 232.70 0.00000*
aging 52962.67 1 52962.67 380.03 0.00000*
Surface Treatment * aging 9582.54 7 1368.93 9.82 0.00000*
Error 50589.95 363 139.37
Total 1043682.62 379
Corrected Total 359509.06 378
Table 60: Estimated Marginal Means (Surface Treatment) Lava Ultimate
Surface Treatment Mean Std. Error
95% Confidence
Interval
Lower
Bound
Upper
Bound
Control 6.69 2.68 1.41 11.97
Airborne Particle Abrasion 64.37 1.67 61.09 67.65
Silane 29.28 1.67 26.00 32.57
Adhesive 10.76 1.69 7.44 14.08
Airborne Particle Abrasion + Silane 68.01 1.67 64.72 71.29
Silane + Adhesive 14.39 1.69 11.07 17.70
Airborne Particle Abrasion + Adhesive 64.02 1.67 60.73 67.30
Airborne Particle Abrasion + Silane +
Adhesive
65.33 1.67 62.04 68.61
93
Group-wise comparisons were performed for different surface treatments of Lava Ultimate
(Table 61) using the Bonferroni method due to multiple comparisons (α=0.05).
Table 61: Group-wise Comparisons (Surface Treatment) in Lava Ultimate
(I) Surface Treatment (J) Surface Treatment
Mean
Difference
(I-J)
Std. Error P Value
95% Confidence
Interval for
Difference
Lower
Bound
Upper
Bound
Control
Airborne Particle Abrasion -57.68 3.16 0.00000* -67.63 -47.74
Silane -22.60 3.16 0.00000* -32.54 -12.65
Adhesive -4.07 3.17 1.00000 -14.05 5.90
Airborne Particle Abrasion + Silane -61.32 3.16 0.00000* -71.26 -51.37
Silane + Adhesive -7.70 3.17 0.43764 -17.67 2.28
Airborne Particle Abrasion +
Adhesive
-57.33 3.16 0.00000* -67.27 -47.38
Airborne Particle Abrasion + Silane
+ Adhesive
-58.64 3.16 0.00000* -68.59 -48.69
Airborne Particle
Abrasion
Silane 35.09 2.36 0.00000* 27.66 42.52
Adhesive 53.61 2.37 0.00000* 46.14 61.08
Airborne Particle Abrasion + Silane -3.64 2.36 1.00000 -11.07 3.79
Silane + Adhesive 49.98 2.37 0.00000* 42.51 57.45
Airborne Particle Abrasion +
Adhesive
0.36 2.36 1.00000 -7.07 7.79
Airborne Particle Abrasion + Silane
+ Adhesive
-0.96 2.36 1.00000 -8.39 6.47
Silane
Adhesive 18.52 2.37 0.00000* 11.06 25.99
Airborne Particle Abrasion + Silane -38.72 2.36 0.00000* -46.15 -31.29
Silane + Adhesive 14.90 2.37 0.00000* 7.43 22.37
Airborne Particle Abrasion +
Adhesive
-34.73 2.36 0.00000* -42.16 -27.30
Airborne Particle Abrasion + Silane
+ Adhesive
-36.04 2.36 0.00000* -43.47 -28.61
Adhesive
Airborne Particle Abrasion + Silane -57.25 2.37 0.00000* -64.72 -49.78
Silane + Adhesive -3.63 2.39 1.00000 -11.13 3.88
Airborne Particle Abrasion +
Adhesive
-53.26 2.37 0.00000* -60.72 -45.79
Airborne Particle Abrasion + Silane
+ Adhesive
-54.57 2.37 0.00000* -62.04 -47.10
Airborne Particle
Abrasion + Silane
Silane + Adhesive 53.62 2.37 0.00000* 46.15 61.09
Airborne Particle Abrasion +
Adhesive
3.99 2.36 1.00000 -3.44 11.42
Airborne Particle Abrasion + Silane
+ Adhesive
2.68 2.36 1.00000 -4.75 10.11
Silane + Adhesive
Airborne Particle Abrasion +
Adhesive
-49.63 2.37 0.00000* -57.10 -42.16
Airborne Particle Abrasion + Silane
+ Adhesive
-50.94 2.37 0.00000* -58.41 -43.47
Airborne Particle
Abrasion + Adhesive
Airborne Particle Abrasion + Silane
+ Adhesive
-1.31 2.36 1.00000 -8.74 6.12
94
The group-wise comparisons between the tested surface treatments in Lava Ultimate presented in
Table 61 . The control group were statistically significant different from all other surface
treatment (p<0.05), except A and SA. While Silane was statistically significant from all other
group. The P, PA, PS, PSA surface treatments were not statistically significant from each other.
(Table 61,Figure 44)
Figure 44: Mean µTBS of different Surface Treatment (Lava Ultimate)
6.69 10.76
14.39
29.28
64.02 64.37 65.33 68.01
0
10
20
30
40
50
60
70
80
90
Control Adhesive Silane +
Adhesive
Silane Airborne
particle
Abrasion +
Adhesive
Airborne
Particle
Abrasion
Airborne
particle
Abrasion +
Silane +
Adhesive
Airborne
particle
Abrasion +
Silane
Mpa
Not sta=s=cally significant
Not sta=s=cally significant
95
3.2.1.2. 1-Way ANOVA
Lava Ultimate Non-Aged
One-way ANOVA was used to evaluate the significance of µTBs values between the different
surface treatments (Table 62, Table 63). There was a statistically significant difference (p=0.000)
between different surface treatments in LU Non-Aged
Table 62: Analysis of Variance of Non-Aged Lava Ultimate (Surface Treatment) and its Interactions
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 187964.219a 7 26852.031 166.141 <.001
Intercept 561307.208 1 561307.208 3472.958 <.001
Surface Treatment 187964.219 7 26852.031 166.141 <.001
Error 31031.467 192 161.622
Total 780302.894 200
Corrected Total 218995.686 199
Group-wise comparisons were performed for different surface treatments of Lava Ultimate
(Table 64) using the Bonferroni method due to multiple comparisons (α=0.05).
Table 63: Estimated Marginal Means (Surface Treatment) Non-Aged Lava Ultimate
Surface Treatment Mean Std. Error
95% Confidence
Interval
Lower
Bound
Upper
Bound
Control 11.831 2.543 6.816 16.846
Airborne Particle Abrasion 80.557 2.543 75.542 85.572
Silane 41.104 2.543 36.089 46.119
Adhesive 18.460 2.543 13.445 23.475
Airborne Particle Abrasion + Silane 81.170 2.543 76.155 86.185
Silane + Adhesive 21.965 2.543 16.950 26.980
Airborne Particle Abrasion + Adhesive 86.033 2.543 81.018 91.048
Airborne Particle Abrasion + Silane + Adhesive 82.695 2.543 77.680 87.710
96
Table 64: Group-wise Comparisons (Surface Treatment) in Non-Aged Lava Ultimate
The group-wise comparisons between the tested surface treatments in Lava Ultimate Non-Aged
presented in Table 64 that the surface treatment of Lava Ultimate including Airborne Particle
Abrasion (P, PA, PS, PSA) were not Statistically significant from each other but statistically
significantly different from all other treatment (C, S, SA, A) (p<0.05). There was not
statistically significant difference between Control and adhesive. Moreover, There was not
statistically significant difference between adhesive and Silane + adhesive groups. But, there was
statistically significant difference between Silane and all other surface treatments. (Table
64,Figure 45)
Materials Aging Surface Treatment
Mean
Difference
(I-J) Std. Error Sig.
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate
Non-Aged
Control
P -68.7264* 3.5958 <.001 -80.1181 -57.3347
S -29.2728* 3.5958 <.001 -40.6645 -17.8811
A -6.6288 3.5958 1 -18.0205 4.7629
PS -69.3388* 3.5958 <.001 -80.7305 -57.9471
SA -10.134 3.5958 0.149 -21.5257 1.2577
PA -74.2024* 3.5958 <.001 -85.5941 -62.8107
PSA -70.8644* 3.5958 <.001 -82.2561 -59.4727
Airborne Particle Abrasion
S 39.4536* 3.5958 <.001 28.0619 50.8453
A 62.0976* 3.5958 <.001 50.7059 73.4893
PS -0.6124 3.5958 1 -12.0041 10.7793
SA 58.5924* 3.5958 <.001 47.2007 69.9841
PA -5.476 3.5958 1 -16.8677 5.9157
PSA -2.138 3.5958 1 -13.5297 9.2537
Silane
A 22.6440* 3.5958 <.001 11.2523 34.0357
PS -40.0660* 3.5958 <.001 -51.4577 -28.6743
SA 19.1388* 3.5958 <.001 7.7471 30.5305
PA -44.9296* 3.5958 <.001 -56.3213 -33.5379
PSA -41.5916* 3.5958 <.001 -52.9833 -30.1999
Adhesive
PS -62.7100* 3.5958 <.001 -74.1017 -51.3183
SA -3.5052 3.5958 1 -14.8969 7.8865
PA -67.5736* 3.5958 <.001 -78.9653 -56.1819
PSA -64.2356* 3.5958 <.001 -75.6273 -52.8439
Airborne particle Abrasion
+ Silane
SA 59.2048* 3.5958 <.001 47.8131 70.5965
PA -4.8636 3.5958 1 -16.2553 6.5281
PSA -1.5256 3.5958 1 -12.9173 9.8661
Silane + Adhesive PA -64.0684* 3.5958 <.001 -75.4601 -52.6767
PSA -60.7304* 3.5958 <.001 -72.1221 -49.3387
Airborne particle Abrasion
+ Adhesive PSA 3.338 3.5958 1 -8.0537 14.7297
97
Figure 45: Mean µTBS of Different Surface Treatment (Non-Aged Lava Ultimate )
11.831
18.46
21.965
41.104
80.557 81.17 82.695
86.033
0
10
20
30
40
50
60
70
80
90
Control Adhesive Silane +
Adhesive
Silane Airborne
Particle
Abrasion
Airborne
particle
Abrasion +
Silane
Airborne
particle
Abrasion +
Silane +
Adhesive
Airborne
particle
Abrasion +
Adhesive
Not
statistically
significant
Not statistically significant
Not
statistically
significant
98
Lava Ultimate Aged
One-way ANOVA was used to evaluate the significance of µTBs values between the different
surface treatments (Table 65 and Table 66). There was a statistically significant difference
(p=0.000) between different surface treatments in LU.A.
Table 65: Analysis of Variance of Aged Lava Ultimate (Surface Treatment) and its Interactions
Source Type III Sum of Squares df Mean
Square
F P Value
Corrected Model 76181.676a 7 10883.097 96.005 <.001
Intercept 109818.908 1 109818.908 968.765 <.001
Surface Treatment 76181.676 7 10883.097 96.005 <.001
Error 19611.219 173 113.360
Total 263379.730 181
Corrected Total 95792.895 180
Group-wise comparisons were performed for different surface treatments of Lava Ultimate
(Table 67) using the Bonferroni method due to multiple comparisons (α=0.05).
Table 66: Estimated Marginal Means (Surface Treatment) Aged Lava Ultimate
Surface Treatment Mean Std. Error
95% Confidence
Interval
Lower
Bound
Upper
Bound
Control 1.547 4.347 -7.033 10.126
Airborne Particle Abrasion 48.185 2.129 43.982 52.388
Silane 17.465 2.129 13.262 21.668
Adhesive 2.939 2.129 -1.264 7.142
Airborne Particle Abrasion + Silane 54.845 2.129 50.642 59.048
Silane + Adhesive 6.540 2.129 2.337 10.743
Airborne Particle Abrasion + Adhesive 41.997 2.129 37.794 46.200
Airborne Particle Abrasion + Silane + Adhesive 47.961 2.129 43.758 52.164
99
Table 67: Group-wise Comparisons (Surface Treatment) in Aged Lava Ultimate
The group-wise comparisons between the tested surface treatments in Lava Ultimate Aged is
presented in Table 67. Shows that the surface treatment of Lava Ultimate including air borne
particle abrasion (P, PA, PS, PSA) were not statistically significant from each other but
statistically significantly different from all other treatment (C,S,SA,A) (p<0.05). There was not
statistically significant difference between control group (C) and adhesive surface treatment.
Also, There was not statistically significant difference between adhesive and Silane +Adhesive
(SA). The silane was statistically significant from all other groups. (Table 67and Figure 46)
Materials Aging Surface Treatment
Mean
Difference
(I-J) Std. Error Sig.
95% Confidence Interval
Lower Bound Upper Bound
Lava Ultimate
Non-Aged
Control
P -68.7264* 3.5958 <.001 -80.1181 -57.3347
S -29.2728* 3.5958 <.001 -40.6645 -17.8811
A -6.6288 3.5958 1 -18.0205 4.7629
PS -69.3388* 3.5958 <.001 -80.7305 -57.9471
SA -10.134 3.5958 0.149 -21.5257 1.2577
PA -74.2024* 3.5958 <.001 -85.5941 -62.8107
PSA -70.8644* 3.5958 <.001 -82.2561 -59.4727
Airborne Particle Abrasion
S 39.4536* 3.5958 <.001 28.0619 50.8453
A 62.0976* 3.5958 <.001 50.7059 73.4893
PS -0.6124 3.5958 1 -12.0041 10.7793
SA 58.5924* 3.5958 <.001 47.2007 69.9841
PA -5.476 3.5958 1 -16.8677 5.9157
PSA -2.138 3.5958 1 -13.5297 9.2537
Silane
A 22.6440* 3.5958 <.001 11.2523 34.0357
PS -40.0660* 3.5958 <.001 -51.4577 -28.6743
SA 19.1388* 3.5958 <.001 7.7471 30.5305
PA -44.9296* 3.5958 <.001 -56.3213 -33.5379
PSA -41.5916* 3.5958 <.001 -52.9833 -30.1999
Adhesive
PS -62.7100* 3.5958 <.001 -74.1017 -51.3183
SA -3.5052 3.5958 1 -14.8969 7.8865
PA -67.5736* 3.5958 <.001 -78.9653 -56.1819
PSA -64.2356* 3.5958 <.001 -75.6273 -52.8439
Airborne particle Abrasion
+ Silane
SA 59.2048* 3.5958 <.001 47.8131 70.5965
PA -4.8636 3.5958 1 -16.2553 6.5281
PSA -1.5256 3.5958 1 -12.9173 9.8661
Silane + Adhesive PA -64.0684* 3.5958 <.001 -75.4601 -52.6767
PSA -60.7304* 3.5958 <.001 -72.1221 -49.3387
Airborne particle Abrasion
+ Adhesive PSA 3.338 3.5958 1 -8.0537 14.7297
100
Figure 46:Mean µTBS of different Surface Treatment (Aged Lava Ultimate)
1.547 2.939
6.54
17.465
41.997
47.961 48.185
54.845
-10
0
10
20
30
40
50
60
70
80
90
Control Adhesive Silane +
Adhesive
Silane Airborne
particle
Abrasion +
Adhesive
Airborne
particle
Abrasion +
Silane +
Adhesive
Airborne
Particle
Abrasion
Airborne
particle
Abrasion +
MPa
Silane
Not
statistically
significant
Not statistically significant
Not
statistically
significant
101
3.2.2. VarseoSmile Crown Plus:
The mean µTBS and standard deviation of VarseoSmile Crown Plus for all different aged and
non-aged surface treatments are presented in Table 68 and Figure 47.
The highest overall mean µTBS value in VarseoSmile Crown Plus was observed with Airborne
Particle Abrasion + Adhesive after aging (VS PA .A; 43.54±6.45 MPa); while the lowest was at
control after aging (VS C.A;9.09±5.25 MPa).
Non-Aged: The µTBS value was highest when treated with Airborne Particle Abrasion + Silane
+ Adhesive (VS PSA.NA; 42.30±5.79 MPa) while the lowest was observed in Silane (VS S.NA;
11.34±5.62 MPa). (PSA>P>PA>PS>A>SA>C>S).
Aged: The µTBS value was highest when treated with Airborne Particle Abrasion + Adhesive
(VS PA .A; 43.54±6.45 MPa), while lowest was in control group (VS C.A; 9.09±5.25 MPa).
(PA>PSA>PS>P>SA>A>S>C).
Table 68: Mean Micro Tensile Bond Strength and Standard Deviation of VarseoSmile Crown Plus
Surface Treatment
Mean NonAged
σ SD NonAged
Mean Aged σ SD Aged
VarseoSmile Crown Plus
Control 12.41 ± 6.37 9.09 ± 5.25
Airborne Particle Abrasion 41.11 ± 7.25 40.66 ± 10.15
Silane 11.34 ± 5.62 12.83 ± 8.93
Adhesive 22.07 ± 10.95 17.45 ± 10.45
Airborne Particle Abrasion + Silane 38.64 ± 5.92 41.63 ± 6.59
Silane + Adhesive 20.15 ± 12.24 19.25 ± 11.36
Airborne Particle Abrasion + Adhesive 40.73 ± 6.47 43.54 ± 6.45
Airborne Particle Abrasion + Silane +
Adhesive
42.30 ± 5.79 41.80 ± 7.40
102
Figure 47: Micro Tensile Bond Strength of VarseoSmile Crown Plus
3.2.2.1. Two-Way ANOVA
Two-way ANOVA was used to evaluate the significance of µTBs values between the different
surface treatments before and after aging (Table 69,Table 70). There was a statistically
significant difference (p=0.000) between different surface treatments in (VS), but it was not
significant before and after aging.
Table 69: Analysis of Variance of VarseoSmile Crown Plus (Surface Treatment, and aging) and their interactions
Source Type III Sum of
Squares
df Mean Square F P Value
Corrected Model 70270.35 15 4684.69 68.53 0.00000
Intercept 323058.67 1 323058.67 4725.80 0.00000
surfacetreatment 69632.27 7 9947.47 145.51 0.00000*
aging 12.16 1 12.16 0.18 0.67340
surfacetreatment * aging 625.93 7 89.42 1.31 0.24503
Error 26250.48 384 68.36
Total 419579.50 400
Corrected Total 96520.83 399
*. The mean difference is significant at the p<0.05 level.
12.41
41.11
11.34
22.07
38.64
20.15
40.73 42.3
9.09
40.66
12.83
17.45
41.63
19.25
43.54 41.8
0
10
20
30
40
50
60
70
80
90
Control Airborne
Particle
Abrasion
Silane Adhesive Airborne
particle
Abrasion +
Silane
Silane +
Adhesive
Airborne
particle
Abrasion +
Adhesive
Airborne
particle
Abrasion +
Silane +
Adhesive
MPa
Non-Aged Aged
103
Table 70: Estimated Marginal Means (Surface Treatment) VarseoSmile Crown Plus
Surface Treatment Mean Std. Error
95% Confidence
Interval
Lower
Bound
Upper
Bound
Control 10.75 1.17 8.45 13.05
Airborne Particle Abrasion 40.89 1.17 38.59 43.19
Silane 12.08 1.17 9.78 14.38
Adhesive 19.76 1.17 17.46 22.06
Airborne Particle Abrasion + Silane 40.13 1.17 37.84 42.43
Silane + Adhesive 19.70 1.17 17.40 22.00
Airborne Particle Abrasion + Adhesive 41.98 1.17 39.69 44.28
Airborne Particle Abrasion + Silane + Adhesive 42.05 1.17 39.75 44.35
Table 71:Group-wise Comparisons (Surface Treatment) in VarseoSmile Crown Plus
(I) Surface Treatment (J) Surface Treatment
Mean
Difference
(I-J)
Std.
Error P Value
95% Confidence Interval
for Difference
Lower
Bound
Upper
Bound
Control
Airborne Particle Abrasion -30.14 1.65 0.00000* -35.34 -24.94
Silane -1.33 1.65 1.00000 -6.54 3.87
Adhesive -9.01 1.65 0.00000* -14.21 -3.81
Airborne Particle Abrasion +
Silane -29.38 1.65 0.00000* -34.59 -24.18
Silane + Adhesive -8.95 1.65 0.00000* -14.15 -3.75
Airborne Particle Abrasion +
Adhesive -31.24 1.65 0.00000* -36.44 -26.03
Airborne Particle Abrasion +
Silane + Adhesive -31.30 1.65 0.00000* -36.50 -26.10
Airborne Particle
Abrasion
Silane 28.81 1.65 0.00000* 23.60 34.01
Adhesive 21.13 1.65 0.00000* 15.93 26.33
Airborne Particle Abrasion +
Silane 0.75 1.65 1.00000 -4.45 5.96
Silane + Adhesive 21.186* 1.65 0.00000* 15.98 26.39
Airborne Particle Abrasion +
Adhesive -1.10 1.65 1.00000 -6.30 4.11
Airborne Particle Abrasion +
Silane + Adhesive -1.16 1.65 1.00000 -6.36 4.04
Silane
Adhesive -7.674* 1.65 0.00013* -12.88 -2.47
Airborne Particle Abrasion +
Silane -28.05 1.65 0.00000* -33.25 -22.85
Silane + Adhesive -7.62 1.65 0.00016* -12.82 -2.42
Airborne Particle Abrasion +
Adhesive -29.90 1.65 0.00000* -35.10 -24.70
Airborne Particle Abrasion +
Silane + Adhesive -29.97 1.65 0.00000* -35.17 -24.77
104
Adhesive
Airborne Particle Abrasion +
Silane -20.38 1.65 0.00000* -25.58 -15.17
Silane + Adhesive 0.05 1.65 1.00000 -5.15 5.26
Airborne Particle Abrasion +
Adhesive -22.23 1.65 0.00000* -27.43 -17.03
Airborne Particle Abrasion +
Silane + Adhesive -22.29 1.65 0.00000* -27.50 -17.09
Airborne Particle
Abrasion + Silane
Silane + Adhesive 20.43 1.65 0.00000* 15.23 25.63
Airborne Particle Abrasion +
Adhesive -1.85 1.65 1.00000 -7.05 3.35
Airborne Particle Abrasion +
Silane + Adhesive -1.92 1.65 1.00000 -7.12 3.28
Silane + Adhesive
Airborne Particle Abrasion +
Adhesive -22.28 1.65 0.00000* -27.48 -17.08
Airborne Particle Abrasion +
Silane + Adhesive -22.35 1.65 0.00000* -27.55 -17.15
Airborne Particle
Abrasion + Adhesive
Airborne Particle Abrasion +
Silane + Adhesive -0.07 1.65 1.00000 -5.27 5.14
*. The mean difference is significant at the p<0.05 level.
Group-wise comparisons were performed for different surface treatments of VarseoSmile Crown
Plus (Table 71) using the Bonferroni method due to multiple comparisons (α=0.05).The
comparisons between the tested surface treatments in VarseoSmile Crown Plus presented that the
control surface treatment of VS aged and non-aged all of them was statistically significantly
different from all other groups (p<0.05) except S. There was statistically significant difference
between S and all other groups . There was not statistically significant difference between P, PA,
PS, and PSA. (Table 71, Figure 48)
105
Figure 48: Mean µTBS of Different Surface Treatments (VarseoSmile Crown Plus)
10.75
12.08
19.70 19.76
40.13 40.89 41.98 42.05
0
10
20
30
40
50
60
70
80
90
Control Silane Silane +
Adhesive
Adhesive Airborne
particle
Abrasion +
Silane
Airborne
Particle
Abrasion
Airborne
particle
Abrasion +
Adhesive
Airborne
particle
Abrasion +
Silane +
Adhesive
Mpa
Not statistically significant
Not
statistically
significant
Not
statistically
significant
106
3.2.2.2. One-Way ANOVA
VarseoSmile Crown Plus Non-Aged
One-way ANOVA was used to evaluate the significance of µTBs values between the different
surface treatments (Table 72,Table 73). There was a statistically significant difference (p=0.000)
between different surface treatments in (VS) Non-Aged
Table 72: Analysis Of Variance Of VarseoSmile Crown Plus Non-Aged (Surface Treatment) and Its Interactions
Source Type III Sum of Squares df Mean
Square
F P Value
Corrected Model 31417.993a 7 4488.285 71.560 <.001
Intercept 163001.087 1 163001.087 2598.858 <.001
Surface Treatment 31417.993 7 4488.285 71.560 <.001
Error 12042.292 192 62.720
Total 206461.371 200
Corrected Total 43460.285 199
Table 73: Estimated Marginal Means (Surface Treatment) VareoSmile Crown Plus Non-Aged
Surface Treatment Mean Std. Error
95% Confidence
Interval
Lower
Bound
Upper
Bound
Control 12.408 1.584 9.283 15.532
Airborne Particle Abrasion 41.113 1.584 37.989 44.237
Silane 11.336 1.584 8.211 14.460
Adhesive 22.068 1.584 18.943 25.192
Airborne Particle Abrasion + Silane 38.642 1.584 35.518 41.766
Silane + Adhesive 20.154 1.584 17.029 23.278
Airborne Particle Abrasion + Adhesive 40.712 1.584 37.588 43.836
Airborne Particle Abrasion + Silane + Adhesive 41.955 1.584 38.831 45.079
Group-wise comparisons were performed for different surface treatments of VarseoSmile Crown
Plus Non-Aged (Table 74) using the Bonferroni method due to multiple comparisons (α=0.05).
The comparisons between the tested surface treatments in VA.NA presented that the (S, C), (C,
107
SA) ,and ( SA, A) surface treatment of VS.NA was not statistically significantly different from
each other(p>0.05). There was not statistically significant difference between all the surface
treatment included Airborne Particle Abrasion P, PA, PS, PSA.(Table 74, Figure 49)
Figure 49: Mean µTBS of Different Surface Treatments (VarseoSmile Crown Plus Non-Aged)
11.336 12.408
20.154 22.068
38.642 40.712 41.113 41.955
0
10
20
30
40
50
60
70
80
90
Silane Control Silane +
Adhesive
Adhesive Airborne
particle
Abrasion +
Silane
Airborne
particle
Abrasion +
Adhesive
Airborne
Particle
Abrasion
Airborne
particle
Abrasion +
Silane +
Adhesive
MPa
Not statistically
significant
Not statistically
significant
Not statistically
significant
Not statistically significant
108
Table 74: Group-wise Comparisons (Surface Treatment) in VarseoSmile Crown Plus Non-Aged
Materials Aging Surface Treatment
Mean
Difference
(I-J) Std. Error Sig.
95% Confidence Interval
Lower Bound Upper Bound
VarseoSmile Crown Plus
Non Aged -
Control
P -28.7052* 2.24 <.001 -35.8017 -21.6087
S 1.072 2.24 1 -6.0245 8.1685
A -9.6600* 2.24 <.001 -16.7565 -2.5635
PS -26.2344* 2.24 <.001 -33.3309 -19.1379
SA -7.7460* 2.24 0.019 -14.8425 -0.6495
PA -28.3044* 2.24 <.001 -35.4009 -21.2079
PSA -29.5476* 2.24 <.001 -36.6441 -22.4511
Airborne Particle Abrasion
S 29.7772* 2.24 <.001 22.6807 36.8737
A 19.0452* 2.24 <.001 11.9487 26.1417
PS 2.4708 2.24 1 -4.6257 9.5673
SA 20.9592* 2.24 <.001 13.8627 28.0557
PA 0.4008 2.24 1 -6.6957 7.4973
PSA -0.8424 2.24 1 -7.9389 6.2541
Silane
A -10.7320* 2.24 <.001 -17.8285 -3.6355
PS -27.3064* 2.24 <.001 -34.4029 -20.2099
SA -8.8180* 2.24 0.003 -15.9145 -1.7215
PA -29.3764* 2.24 <.001 -36.4729 -22.2799
PSA -30.6196* 2.24 <.001 -37.7161 -23.5231
Adhesive
PS -16.5744* 2.24 <.001 -23.6709 -9.4779
SA 1.914 2.24 1 -5.1825 9.0105
PA -18.6444* 2.24 <.001 -25.7409 -11.5479
PSA -19.8876* 2.24 <.001 -26.9841 -12.7911
Airborne particle Abrasion
+ Silane
SA 18.4884* 2.24 <.001 11.3919 25.5849
PA -2.07 2.24 1 -9.1665 5.0265
PSA -3.3132 2.24 1 -10.4097 3.7833
Silane + Adhesive
PA -20.5584* 2.24 <.001 -27.6549 -13.4619
PSA -21.8016* 2.24 <.001 -28.8981 -14.7051
Airborne particle Abrasion
+ Adhesive
PSA -1.2432 2.24 1 -8.3397 5.8533
109
VarseoSmile Crown Plus Aged
One-way ANOVA was used to evaluate the significance of µTBs values between the different
surface treatments (Table 75, Table 76). There was a statistically significant difference (p=0.000)
between different surface treatments in VS.A.
Table 75: Analysis of Variance of VarseoSmile Crown Plus Aged (Surface Treatment) and its Interactions
Source Type III Sum of Squares df Mean
Square
F P Value
Corrected Model 38845.191a 7 5549.313 74.987 <.001
Intercept 160064.254 1 160064.254 2162.927 <.001
surface treatment 38845.191 7 5549.313 74.987 <.001
Error 14208.681 192 74.004
Total 213118.126 200
Corrected Total 53053.871 199
Group-wise comparisons were performed for different surface treatments of Lava Ultimate
(Table 77) using the Bonferroni method due to multiple comparisons (α=0.05).
Table 76: Estimated Marginal Means (Surface Treatment) VarseoSmile Crown Plus Aged
Surface Treatment Mean Std. Error
95% Confidence
Interval
Lower
Bound
Upper
Bound
Control 9.092 1.721 5.698 12.486
Airborne Particle Abrasion 40.664 1.721 37.271 44.058
Silane 12.832 1.721 9.438 16.225
Adhesive 17.448 1.721 14.054 20.842
Airborne Particle Abrasion + Silane 41.626 1.721 38.232 45.020
Silane + Adhesive 19.252 1.721 15.858 22.646
Airborne Particle Abrasion + Adhesive 43.258 1.721 39.864 46.651
Airborne Particle Abrasion + Silane + Adhesive 42.148 1.721 38.754 45.542
110
Table 77: Group-wise Comparisons (Surface Treatment) in VarseoSmile Crown Plus Aged
Materials Aging Surface Treatment
Mean
Difference
(I-J) Std. Error Sig.b
95% Confidence Intervalb
Lower Bound Upper Bound
VarseoSmile Crown Plus
Aged
Control
P -31.572* 2.433 <.001 -39.281 -23.864
S -3.74 2.433 1 -11.448 3.969
A -8.356* 2.433 0.02 -16.064 -0.648
PS -32.534* 2.433 <.001 -40.242 -24.826
SA -10.160* 2.433 0.001 -17.868 -2.452
PA -34.166* 2.433 <.001 -41.874 -26.457
PSA -33.056* 2.433 <.001 -40.764 -25.348
Airborne Particle Abrasion
S 27.833* 2.433 <.001 20.124 35.541
A 23.216* 2.433 <.001 15.508 30.925
PS -0.962 2.433 1 -8.67 6.747
SA 21.412* 2.433 <.001 13.704 29.121
PA -2.593 2.433 1 -10.302 5.115
PSA -1.484 2.433 1 -9.192 6.225
Silane
A -4.616 2.433 1 -12.325 3.092
PS -28.794* 2.433 <.001 -36.503 -21.086
SA -6.42 2.433 0.252 -14.129 1.288
PA -30.426* 2.433 <.001 -38.134 -22.718
PSA -29.316* 2.433 <.001 -37.025 -21.608
Adhesive
PS -24.178* 2.433 <.001 -31.886 -16.47
SA -1.804 2.433 1 -9.512 5.904
PA -25.810* 2.433 <.001 -33.518 -18.101
PSA -24.700* 2.433 <.001 -32.408 -16.992
Airborne particle Abrasion
+ Silane
SA 22.374* 2.433 <.001 14.666 30.082
PA -1.632 2.433 1 -9.34 6.077
PSA -0.522 2.433 1 -8.23 7.186
Silane + Adhesive
PA -24.006* 2.433 <.001 -31.714 -16.297
PSA -22.896* 2.433 <.001 -30.604 -15.188
Airborne particle Abrasion
+ Adhesive
PSA 1.11 2.433 1 -6.599 8.818
111
Figure 50: Mean µTBS of Different Surface Treatments (VarseoSmile Crown Plus Aged)
Group-wise comparisons were performed for different surface treatments of VarseoSmile Crown
Plus Aged (Table 77) using the Bonferroni method due to multiple comparisons (α=0.05). The
comparisons between the tested surface treatments in VA. A presented that the (S, C), (S, A),and
(A, SA) surface treatment of VS.NA was not statistically significantly different from each other
(p>0.05). There was not statistically significant difference between all the surface treatment
included Airborne Particle Abrasion P, PA, PS, PSA.(Table 77, Figure 50)
9.092
12.832
17.448 19.252
40.664 41.626 42.148 43.258
0
10
20
30
40
50
60
70
80
90
Control Silane Adhesive Silane +
Adhesive
Airborne
Particle
Abrasion
Airborne
particle
Abrasion +
Silane
Airborne
particle
Abrasion +
Silane +
Adhesive
Airborne
particle
Abrasion +
Adhesive
Mean MPa
Not statistically
significant Not statistically
significant
Not statistically significant
Not statistically
significant
112
3.2.3. Ceramic Crown:
The mean µTBS and standard deviation of Ceramic Crown for the different surface treatments
for both aged non aged are presented in Table 78 and Figure 51.
The highest overall mean µTBS value in Ceramic Crown was observed at Airborne Particle
Abrasion + Adhesive after aging (CC PA. A; 56.77±9.70 MPa); while the lowest was at control
after aging (CC C.A; 8.87±6.88 MPa).
Figure 51: Micro Tensile Bond Strength of Ceramic Crown
24.73
49.23
43.48 44.4
49.03 47.35
56.05 52.71
8.87
40.22 37.73
11.22
56.58
43.12
56.77
47.04
0
10
20
30
40
50
60
70
80
90
Control Airborne
Particle
Abrasion
Silane Adhesive Airborne
particle
Abrasion +
Silane
Silane +
Adhesive
Airborne
particle
Abrasion +
Adhesive
Airborne
particle
Abrasion +
Silane +
Adhesive
MPa
Non-Aged Aged
Table 78: Mean Micro Tensile Bond Strength and Standard Deviation of Ceramic crown
Surface Treatment Mean NonAged
σ SD NonAged
Mean Aged σ SD Aged
Ceramic crown
Control 24.73 ± 8.87 8.87 ± 6.88
Airborne Particle Abrasion 49.23 ± 9.12 40.22 ± 11.87
Silane 43.48 ± 8.95 37.73 ± 12.65
Adhesive 44.40 ± 11.22 11.22 ± 10.22
Airborne Particle Abrasion + Silane 49.03 ± 9.02 56.58 ± 10.58
Silane + Adhesive 47.35 ± 12.20 43.12 ± 12.28
Airborne Particle Abrasion + Adhesive 56.05 ± 7.66 56.77 ± 9.70
Airborne Particle Abrasion + Silane + Adhesive 52.71 ± 11.03 47.04 ± 4.69
113
Non-Aged: The µTBS value was highest when treated with Airborne Particle Abrasion +
Adhesive (CC PA.NA; 56.05 ±7.66 MPa) while the lowest in control (CC C.NA; 24.73 ± 8.87
MPa). (PA>PSA>P>PS>SA>A>S>C).
Aged: The µTBS value was highest when treated with Airborne Particle Abrasion+ Adhesive
(CC PA.A; 56.77±9.70 MPa ). While the lowest in control (CC C.A; 8.87±6.88 MPa).
(PA>PS>PSA>SA>P>S>A>C).
3.2.3.1. Two-Way ANOVA
Two-way ANOVA was used to evaluate the significance of µTBS values between the different
surface treatments before and after aging (Table 79, Table 80). There was a statistically
significant difference (p=0.000) between different surface treatments in (CC) before and after
aging.
Table 79: Analysis of Variance of Ceramic Crown (Surface Treatment, and Aging) and Their Interactions
Source Type III Sum of Squares df Mean
Square
F P Value
Corrected Model 46451.683a 15 3096.78 30.78 0.00000
Intercept 768733.52 1 768733.52 7641.25 0.00000
Surface Treatment 42047.14 7 6006.73 59.71 0.00000*
aging 1652.87 1 1652.87 16.43 0.00006*
Surface Treatment * aging 2751.67 7 393.10 3.91 0.00039*
Error 38631.60 384 100.60
Total 853816.81 400
Corrected Total 85083.29 399
a. R Squared = .546 (Adjusted R Squared = .528)
114
Table 80: Estimated Marginal Means (Surface Treatment) Ceramic Crown
Surface Treatment Mean Std. Error
95% Confidence
Interval
Lower
Bound
Upper
Bound
Control 20.56 1.42 17.78 23.35
Airborne Particle Abrasion 44.73 1.42 41.94 47.52
Silane 40.61 1.42 37.82 43.40
Adhesive 40.49 1.42 37.70 43.28
Airborne Particle Abrasion + Silane 52.81 1.42 50.02 55.59
Silane + Adhesive 45.23 1.42 42.45 48.02
Airborne Particle Abrasion + Adhesive 56.41 1.42 53.62 59.20
Airborne Particle Abrasion + Silane +
Adhesive
49.87 1.42 47.09 52.66
Group-wise comparisons were performed for different surface treatments of Ceramic Crown
(Table 81) using the Bonferroni method due to multiple comparisons (α=0.05).
Table 81: Group-wise Comparisons (Surface Treatment) in Ceramic Crown
(I) Surface
Treatment (J) Surface Treatment
Mean
Difference
(I-J)
Std.
Error P Value
95% Confidence Interval
for Difference
Lower
Bound
Upper
Bound
Control
Airborne Particle Abrasion -24.16 2.01 0.00000* -30.47 -17.85
Silane -20.04 2.01 0.00000* -26.35 -13.73
Adhesive -19.92 2.01 0.00000* -26.23 -13.61
Airborne Particle Abrasion +
Silane -32.24 2.01 0.00000* -38.55 -25.93
Silane + Adhesive -24.67 2.01 0.00000* -30.98 -18.36
Airborne Particle Abrasion +
Adhesive -35.84 2.01 0.00000* -42.15 -29.53
Airborne Particle Abrasion +
Silane + Adhesive -29.31 2.01 0.00000* -35.62 -23.00
Airborne Particle
Abrasion
Silane 4.12 2.01 1.00000 -2.19 10.43
Adhesive 4.24 2.01 0.98342 -2.07 10.55
Airborne Particle Abrasion +
Silane -8.077* 2.01 0.00191* -14.39 -1.77
Silane + Adhesive -0.51 2.01 1.00000 -6.82 5.80
115
Airborne Particle Abrasion +
Adhesive -11.68 2.01 0.00000* -17.99 -5.37
Airborne Particle Abrasion +
Silane + Adhesive -5.15 2.01 0.29919 -11.46 1.16
Silane
Adhesive 0.12 2.01 1.00000 -6.19 6.43
Airborne Particle Abrasion +
Silane -12.20 2.01 0.00000* -18.51 -5.89
Silane + Adhesive -4.63 2.01 0.60464 -10.94 1.68
Airborne Particle Abrasion +
Adhesive -15.80 2.01 0.00000* -22.11 -9.49
Airborne Particle Abrasion +
Silane + Adhesive -9.27 2.01 0.00015* -15.58 -2.96
Adhesive
Airborne Particle Abrasion +
Silane -12.32 2.01 0.00000* -18.63 -6.01
Silane + Adhesive -4.75 2.01 0.51630 -11.06 1.56
Airborne Particle Abrasion +
Adhesive -15.92 2.01 0.00000* -22.23 -9.61
Airborne Particle Abrasion +
Silane + Adhesive -9.39 2.01 0.00011* -15.70 -3.08
Airborne Particle
Abrasion + Silane
Silane + Adhesive 7.57 2.01 0.00520* 1.26 13.88
Airborne Particle Abrasion +
Adhesive -3.60 2.01 1.00000 -9.91 2.71
Airborne Particle Abrasion +
Silane + Adhesive 2.93 2.01 1.00000 -3.38 9.24
Silane + Adhesive
Airborne Particle Abrasion +
Adhesive -11.18 2.01 0.00000* -17.49 -4.86
Airborne Particle Abrasion +
Silane + Adhesive -4.64 2.01 0.59496 -10.95 1.67
Airborne Particle
Abrasion +
Adhesive
Airborne Particle Abrasion +
Silane + Adhesive 6.54 2.01 0.03427* 0.22 12.85
The group-wise comparisons between the tested surface treatments in Ceramic Crown presented
that all the tested surface treatment of CC of aged and non-aged sample was statistically
significantly different from the control group (p<0.05). There was not statistically significant
difference between S, A, SA, P ,and PSA. Also, there was not statistically significant difference
between PA and PS. (Table 81 and Figure 52)
116
Figure 52: Mean µTBS of Different Surface Treatments (Ceramic Crown)
3.2.3.2. One-Way ANOVA
Ceramic Crown Non-Aged
One-way ANOVA was used to evaluate the significance of µTBs values between the different
surface treatments (Table 82,Table 83). There was a statistically significant difference
(p=0.000) between different surface treatments in CC.NA.
Table 82: Analysis of Variance of Ceramic Crown Non- Aged (Surface Treatment) and its Interactions
Source Type III Sum of Squares df Mean
Square
F P Value
Corrected Model 15718.274a 7 2245.468 23.087 <.001
Intercept 420838.902 1 420838.902 4326.823 <.001
Surface Treatment 15718.274 7 2245.468 23.087 <.001
Error 18674.455 192 97.263
Total 455231.632 200
Corrected Total 34392.729 199
20.56
40.49 40.61
44.73 45.23
49.87 52.81
56.41
0
10
20
30
40
50
60
70
80
90
Control Adhesive Silane Airborne
Particle
Abrasion
Silane +
Adhesive
Airborne
particle
Abrasion +
Silane +
Adhesive
Airborne
particle
Abrasion +
Silane
Airborne
particle
Abrasion +
Adhesive
Mpa
Not statistically significant
Not
statistically
significant
117
Group-wise comparisons were performed for different surface treatments of Ceramic Crown
(Table 84) using the Bonferroni method due to multiple comparisons (α=0.05).
Table 83: Estimated Marginal Means (Surface Treatment) Ceramic Crown Non- Aged
The group-wise comparisons between the tested surface treatments in non-aged Ceramic Crown
sample all surface treatments were statistically significantly different from the control group
(p<0.05). There was not statistically significant difference between P and S, A, SA, PS, PA,
PSA. The S was statistically significant from all groups except PA, PSA .There was
statistically significant difference between A and PA,PSA. Lastly, There was not
statistically significant difference between S, A, SA, PA. (Table 84, Figure 53)
Surface Treatment Mean Std. Error
95% Confidence
Interval
Lower
Bound
Upper
Bound
Control 24.727 1.972 20.836 28.617
Airborne Particle Abrasion 49.233 1.972 45.343 53.124
Silane 43.482 1.972 39.592 47.373
Adhesive 44.397 1.972 40.506 48.287
Airborne Particle Abrasion + Silane 49.026 1.972 45.136 52.917
Silane + Adhesive 47.350 1.972 43.460 51.240
Airborne Particle Abrasion + Adhesive 56.049 1.972 52.158 59.939
Airborne Particle Abrasion + Silane + Adhesive 52.708 1.972 48.817 56.598
118
Table 84 :Group-wise Comparisons (Surface Treatment) in Non-Aged Ceramic Crown
Materials Aging Surface Treatment
Mean
Difference
(I-J) Std. Error Sig.
95% Confidence Interval
Lower Bound Upper Bound
Ceramic Crown
Non Aged -
Control
P -24.506* 2.789 <.001 -33.344 -15.669
S -18.756* 2.789 <.001 -27.593 -9.918
A -19.670* 2.789 <.001 -28.507 -10.833
PS -24.300* 2.789 <.001 -33.137 -15.462
SA -22.623* 2.789 <.001 -31.46 -13.786
PA -31.322* 2.789 <.001 -40.159 -22.485
PSA -27.981* 2.789 <.001 -36.818 -19.144
Airborne Particle Abrasion
S 5.751 2.789 1 -3.086 14.588
A 4.836 2.789 1 -4.001 13.674
PS 0.207 2.789 1 -8.63 9.044
SA 1.883 2.789 1 -6.954 10.72
PA -6.816 2.789 0.433 -15.653 2.022
PSA -3.474 2.789 1 -12.312 5.363
Silane
A -0.914 2.789 1 -9.752 7.923
PS -5.544 2.789 1 -14.381 3.293
SA -3.868 2.789 1 -12.705 4.97
PA -12.566* 2.789 <.001 -21.404 -3.729
PSA -9.225* 2.789 0.031 -18.062 -0.388
Adhesive
PS -4.63 2.789 1 -13.467 4.208
SA -2.953 2.789 1 -11.79 5.884
PA -11.652* 2.789 0.001 -20.489 -2.815
PSA -8.311 2.789 0.091 -17.148 0.526
Airborne particle Abrasion
+ Silane
SA 1.676 2.789 1 -7.161 10.514
PA -7.022 2.789 0.354 -15.86 1.815
PSA -3.681 2.789 1 -12.518 5.156
Silane + Adhesive
PA -8.699 2.789 0.059 -17.536 0.138
PSA -5.358 2.789 1 -14.195 3.48
Airborne particle Abrasion
+ Adhesive
PSA 3.341 2.789 1 -5.496 12.178
119
Figure 53: Mean µTBS of Different Surface Treatments (Ceramic Crown Non-Aged)
Ceramic Crown Aged
One-way ANOVA was used to evaluate the significance of µTBs values between the different
surface treatments (Table 85, Table 86). There was a statistically significant difference
(p=0.000) between different surface treatments in CC.A.
Table 85: Analysis of Variance of Ceramic Crown Aged (Surface Treatment) and its Interactions.
Source Type III Sum of Squares df Mean
Square
F P Value
Corrected Model 29080.540a 7 4154.363 39.968 <.001
Intercept 349547.491 1 349547.491 3362.861 <.001
Surface Treatment 29080.540 7 4154.363 39.968 <.001
Error 19957.146 192 103.943
Total 398585.177 200
Corrected Total 49037.686 199
24.727
43.482 44.397 47.35 49.026 49.233
52.708
56.049
0
10
20
30
40
50
60
70
80
90
Control Silane Adhesive Silane +
Adhesive
Airborne
particle
Abrasion +
Silane
Airborne
Particle
Abrasion
Airborne
particle
Abrasion +
Silane +
Adhesive
Airborne
particle
Abrasion +
Adhesive
MPa
120
Group-wise comparisons were performed for different surface treatments of Ceramic Crown
(Table 87) using the Bonferroni method due to multiple comparisons (α=0.05).
Table 86: Estimated Marginal Means (Surface Treatment) Ceramic Crown Aged
The group-wise comparisons between the tested surface treatments in Ceramic Crown presented
that all the tested surface treatment of CC of aged and aged sample was significantly different
from the control group (p<0.05). There was not statistically significant difference between S, A,
SA, P, PSA. Also, there was not statistically significant difference between PA, PS. (Table 87,
Figure 54)
Surface Treatment Mean Std. Error
95% Confidence
Interval
Lower
Bound
Upper
Bound
Control 16.403 2.039 12.381 20.425
Airborne Particle Abrasion 40.223 2.039 36.201 44.245
Silane 37.731 2.039 33.709 41.753
Adhesive 36.576 2.039 32.555 40.598
Airborne Particle Abrasion + Silane 56.585 2.039 52.563 60.607
Silane + Adhesive 43.119 2.039 39.097 47.141
Airborne Particle Abrasion + Adhesive 56.769 2.039 52.747 60.791
Airborne Particle Abrasion + Silane + Adhesive 47.041 2.039 43.019 51.063
121
Table 87: Group-wise Comparisons (Surface Treatment) in Aged Ceramic Crown
Materials Aging Surface Treatment
Mean
Difference
(I-J) Std. Error Sig.
95% Confidence Interval
Lower Bound Upper Bound
Ceramic Crown
Non-Aged
Control
P -23.820* 2.884 <.001 -32.956 -14.685
S -21.328* 2.884 <.001 -30.464 -12.193
A -20.174* 2.884 <.001 -29.309 -11.038
PS -40.182* 2.884 <.001 -49.318 -31.046
SA -26.716* 2.884 <.001 -35.852 -17.58
PA -40.366* 2.884 <.001 -49.502 -31.231
PSA -30.638* 2.884 <.001 -39.774 -21.503
Airborne Particle Abrasion
S 2.492 2.884 1 -6.644 11.628
A 3.647 2.884 1 -5.489 12.782
PS -16.362* 2.884 <.001 -25.497 -7.226
SA -2.896 2.884 1 -12.031 6.24
PA -16.546* 2.884 <.001 -25.682 -7.41
PSA -6.818 2.884 0.534 -15.954 2.318
Silane
A 1.155 2.884 1 -7.981 10.29
PS -18.854* 2.884 <.001 -27.989 -9.718
SA -5.388 2.884 1 -14.523 3.748
PA -19.038* 2.884 <.001 -28.174 -9.902
PSA -9.310* 2.884 0.041 -18.446 -0.174
Adhesive
PS -20.008* 2.884 <.001 -29.144 -10.873
SA -6.542 2.884 0.683 -15.678 2.593
PA -20.193* 2.884 <.001 -29.328 -11.057
PSA -10.465* 2.884 0.01 -19.6 -1.329
Airborne particle Abrasion
+ Silane
SA 13.466* 2.884 <.001 4.33 22.602
PA -0.184 2.884 1 -9.32 8.951
PSA 9.544* 2.884 0.031 0.408 18.679
Silane + Adhesive
PA -13.650* 2.884 <.001 -22.786 -4.515
PSA -3.922 2.884 1 -13.058 5.213
Airborne particle Abrasion
+ Adhesive
PSA 9.728* 2.884 0.025 0.592 18.864
122
Figure 54: Mean µTBS of Different Surface Treatments (Ceramic Crown Aged)
16.403
36.576 37.731 40.223 43.119
47.041
56.585 56.769
0
10
20
30
40
50
60
70
80
90
Control Adhesive Silane Airborne
Particle
Abrasion
Silane +
Adhesive
Airborne
particle
Abrasion +
Silane +
Adhesive
Airborne
particle
Abrasion +
Silane
Airborne
particle
Abrasion +
Adhesive
MPa
Not Statistically significant
Not Statistically significant
123
3.3.Artificial Aging:
Overall:
The µTBS data showed that non-Aged had the highest µTBS values, and it reduced significantly
after aging (non-Aged>Aged) (Table 88). The group-wise comparisons of Non-Aged (NA) Aged
(A) presented that The Aging of different materials regardless of the surface treatment was
generally statistically significantly different (p<0.05) from each other. (Table 89,and Figure 55)
Table 88: Estimated Marginal Means (Aging)
Time Mean Std. Error
95% Confidence
Interval
Lower
Bound
Upper
Bound
Non-Aged 42.481 .413 41.671 43.290
Aged 32.595 .440 31.744 33.471
Table 89: Group-wise Comparisons (Aging)
Mean Difference (I-J) Std. Error P Value
95% Confidence Interval for
Difference
Lower Bound Upper
Bound
Non-Aged Aged 9.87 0.60 0.00000* 8.69 11.06
124
Figure 55: Mean µTBS of different material before and after aging
125
3.3.1. Lava Ultimate:
The µTBS data of LU showed that non-Aged had the highest µTBS values, and it reduced
significantly after aging (non-Aged>Aged) (Table 90). The group-wise comparisons between
Non-Aged (NA) Aged(A) presented that the Aging of Lava Ultimate regardless of the surface
treatment was generally statistically significantly different (p<0.05) from each other. (Table 91
,and Figure 56)
Table 90: Estimated Marginal Means of Lava Ultimate (Aging)
time Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Non-Aged 52.977 .835 51.335 54.618
Aged 27.734 .990 25.787 29.680
Table 91: Group-wise Comparisons Lava Ultimate (Aging)
Mean Difference (IJ) Std. Error P Value
95% Confidence
Interval for Difference
Lower
Bound
Upper
Bound
Non-Aged Aged 25.24 1.29 0.00000 22.70 27.79
Figure 56: Mean µTBS of Lava Ultimate before and after aging
126
3.3.2. VarseoSmile Crown Plus:
The µTBS data of VS showed that non-Aged had the highest µTBS values, and it reduced not
significantly after aging (non-Aged>Aged) (Table 92). The group-wise comparisons between the
Non-Aged (NA) Aged(A) presented that Aging of Lava Ultimate regardless of the surface
treatment was generally Not statistically significantly different (p>0.05) from each other. (Table
93 ,and Figure 57Error! Reference source not found.)
Table 92: Estimated Marginal Means of VarseoSmile Crown Plus (Aging)
Time Mean Std. Error
95% Confidence Interval
Lower Bound Upper Bound
Non-Aged 28.594 .585 27.444 29.743
Aged 28.245 .585 27.095 29.394
Table 93:Group-wise Comparisons VarseoSmile Crown Plus (Aging)
(I) (J ) Mean Difference
(I-J) Std. Error P Value
95% Confidence Interval for
Difference
Lower Bound Upper
Bound
Non-Aged Aged 0.35 0.83 0.67340 -1.28 1.97
Figure 57: Mean µTBS of VarseoSmile Crown Plus before and after aging
127
3.3.3. Ceramic crown:
The µTBS data of CC showed that non-Aged had the highest MTB values, and it reduced
significantly after aging (non-Aged>Aged)( Table 94 ).The group-wise comparisons between the
Non-Aged (.NA) Aged(.A) presented that The Aging of Ceramic Crown regardless of the
surface treatment was generally statistically significantly different (p>0.05) from each other.
(Table 93 and Figure 58Error! Reference source not found.)
Table 94: Estimated Marginal Means of Ceramic Crown (Aging)
time Mean Std.
Error
95% Confidence Interval
Lower Bound Upper Bound
Non-Aged 45.872 .709 44.477 47.266
Aged 41.806 .709 40.411 43.200
Table 95: Group-wise Comparisons Ceramic Crown (Aging)
I J Mean Difference
(I-J) Std. Error P Value
95% Confidence
Interval for
Difference
Lower
Bound
Upper
Bound
Non-Aged Aged 4.07 1.00 0.00006 2.09 6.04
Figure 58: Mean µTBS of Ceramic Crown before and after aging
128
4. Analysis of Failure Mode:
4.1.Overall:
The failure mode distribution data showed that the most common type of failure in tested
materials was adhesive (49.8%) followed by cohesive in materials (38.8%), mixed (5.1%),
cohesive in cement (4.7%), and lastly pre-testing failure (1.8%)(Table 96 and
Figure 59).
Table 96: Failures mode distribution
Failure mode Frequency Percent
Adhesive 597 49.8%
Cohesive in cement 56 4.7%
Cohesive in material 465 38.8%
Mixed 61 5.1%
Pre-testing failure 21 1.8%
Total 1200 100.0%
Figure 59: Percent of different failure modes
49.8
38.8
5.1 4.7 1.8
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
Adhesive Cohesive in material Mixed Cohesive in cement Pre-testing failure
Percent %
129
4.2. Relation of Failure Mode and Material:
Lava Ultimate shows the Highest percentage of Adhesive failure mode (61.8%). Also, the
VarseoSmile Crown Plus has a high percentage of Adhesive failure mode (49.5%) but it’s close
to the percentage of Cohesive in material failure (43.3%). Ceramic crowns most common type of
failure cohesive in material (61.3%) (Table 97,and Figure 55).
Table 97: Percentage of type of failure and materials.
failure mode
Adhesive Total
Cohesive
in cement
Cohesive
in material Mixed
Pre-testing
failure
Material
Lava Ultimate
247 36 47 49 21 400
61.8%* 9.0% 11.8% 12.3% 5.3% 100.0%
VarseoSmile Crown Plus
198 19 173 10 0 400
49.5%* 4.8% 43.3% 2.5% 0.0% 100.0%
Ceramic Crown
152 1 245 2 0 400
38.0% .3% 61.3%* .5% 0.0% 100.0%
Total
597 56 465 61 21 1200
49.8% 4.7% 38.8% 5.1% 1.8% 100.0%
Figure 60: Percentage of failure modes in different materials
61.8%
49.5%
38.0%
9.0%
4.8%
.3%
11.8%
43.3%
61.3%
12.3%
2.5%
.5%
5.3%
0.0%
0.0%
LAVA ULTIMATE
VARSEOSMILE CROWN PLUS
CERAMIC CROWN
Adhesive Cohesive in Cement Cohesive in Material Mixed Pre-testing failure
130
4.3. Relation of Failure Mode and Surface Treatment:
Adhesive failure has a higher frequency when surface treatment doesn’t include Airborne
Particle Abrasion. While Cohesive in material failure has a higher frequency when the treatment
included Airborne Particle Abrasion (Table 98, Error! Reference source not found.)
Table 98: Percentage of Failure Mode in Surface Treatment
failure mode
Total
Adhesive
Cohesive
in cement
Cohesive
in
material
Mixed
Pretesting
failure
Surface Treatment
Control
127 2 0 2 19 150
84.7%* 1.3% 0.0% 1.3% 12.7%* 100.0%
Airborne Particle Abrasion
42 13 83 12 0 150
28.0% 8.7% 55.3% 8.0% 0.0% 100.0%
Silane
115 10 22 3 0 150
76.7% 6.7%* 14.7% 2.0% 0.0% 100.0%
Adhesive
110 7 28 4 1 150
73.3% 4.7% 18.7% 2.7% 0.7% 100.0%
Airborne Particle Abrasion + Silane
31 10 104 5 0 150
20.7% 6.7% 69.3%* 3.3% 0.0% 100.0%
Silane + Adhesive
92 3 32 22 1 150
61.3% 2.0% 21.3% 14.7% 0.7% 100.0%
Airborne Particle Abrasion + Adhesive
32 7 101 10 0 150
21.3% 4.7% 67.3% 6.7%* 0.0% 100.0%
Airborne Particle Abrasion + Silane +
Adhesive
48 4 95 3 0 150
32.0% 2.7% 63.3% 2.0% 0.0% 100.0%
Total
597 56 465 61 21 1200
49.8% 4.7% 38.8% 5.1% 1.8% 100.0%
131
Figure 61: Percentage of failure modes with Different Surface Treatments
132
4.4. Relation of Failure Mode and Aging:
Before aging the most frequent type of failure was Cohesive in material, while the most frequent
type of failure after aging was Adhesive.( Table 99,Figure 85)
Table 99: Percentage of Failure Mode Based on Aging
Figure 62: Bar Graph in Percentage of Failure Modes Based on Aging
41.5%
6.3%
46.5%
5.7%
0.0%
58.0%
3.0%
31.0%
4.5%
0.0% 3.5%
20.0%
40.0%
60.0%
80.0%
100.0%
120.0%
Adhesive Cohesive in
cement
Cohesive in
material
Mixed Pre-testing
failure
Non-Aged Aged
Failure mMode
Total
Adhesive
Cohesive
in cement
Cohesive
in
material
Mixed
Pretesting
failure
Ageing
Non-Aged
249 38 279 34 0 600
41.5% 6.3% 46.5%* 5.7% 0.0% 100.0%
Aged
348 18 186 27 21 600
58.0%* 3.0% 31.0% 4.5% 3.5% 100.0%
Total 597 56 465 61 21 1200
49.8% 4.7% 38.8% 5.1% 1.8% 100.0%
133
5. Weibull Analysis:
The Two-parameter Weibull distribution are described using a shape (Weibull modulus)
parameter as well as a scaling (characteristic strength) parameter. They are estimated from the
Micro tensile bonding strength data.
The Weibull modulus signifies the shape parameter that affects the slope of the data on the
Weibull plot. Also, the Weibull plot represents the Weibull Characteristic Strength that indicates
the scale parameter and affects the spread of the distribution.
Weibull statistics were performed to analyze the micro tensile bonding strength data. R (v4.2.1;
R Core Team 2022, PBC, Boston, MA, USA) was used to calculate the Weibull Modulus (�)
and Weibull Characteristic Strength (σ�) as well as obtain Weibull plots and likelihood contour
plots.
The Weibull distribution Two parameters of the micro tensile bonding strength data of Lava
Ultimate, VarseoSmile Crown Plus, and ceramic crown are presented in Table 100.
134
Table 100: Weibull distribution (Two-parameters) Characteristic Strength (��) and Weibull Modulus (m) of Lava Ultimate , VarseoSmile Crown
Plus, and Ceramic Crown Materials
Group
Group No. &
Abrev.
Weibull parameters
Weibull Characteristic Strength
(σ�) Weibull Modulus (� )
σ
Mean σ SD
σ�
Upper
bound
σ�
Lower
bound
�
Mean
�
SD
�
Upper
bond
�
Lower
bond
Lava Ultimate
Control Non-Aged 1-LU.C.NA 13.08 0.75 14.55 11.61 3.64 0.60 4.80 2.47
Control Aged 2-LU.C.A 1.70 0.48 2.64 0.75 1.50 0.53 2.55 0.45
Airborne Particle Abrasion Non-Aged 3-LU.P.NA 87.04 3.23 93.37 80.71 5.59 0.94 7.43 3.76
Airborne Particle Abrasion Aged 4-LU.P.A 52.74 2.61 57.86 47.62 4.22 0.66 5.52 2.92
silane Non-Aged 5-LU.S.NA 46.25 3.37 52.86 39.64 2.89 0.46 3.80 1.98
silane Aged 6-LU.S.A 19.80 1.97 23.66 15.93 2.13 0.30 2.72 1.55
Adhesive Non-Aged 7-LU.A.NA 20.48 1.25 22.93 18.04 3.48 0.50 4.47 2.49
Adhesive Aged 8-LU.A.A 3.06 0.54 4.13 2.00 1.17 0.21 1.57 0.76
Airborne Particle Abrasion and Silane
Non-Aged
9-LU.PS.NA 86.67 2.89 92.34 81.00 6.37 0.90 8.13 4.61
Airborne Particle Abrasion & Silane Aged 10-LU.PS.A 60.08 2.84 65.65 54.51 4.46 0.69 5.80 3.11
silane & Adhesive Non-Aged 11-LU.SA.NA 24.35 1.79 27.86 20.83 2.83 0.45 3.72 1.94
silane & Adhesive Aged 12-LU.SA.A 7.20 0.82 8.80 5.61 1.83 0.31 2.44 1.21
Airborne Particle Abrasion & Adhesive
Non-Aged
13-LU.PA.NA 92.80 3.24 99.15 86.45 6.04 0.96 7.92 4.16
Airborne Particle Abrasion & Adhesive
Aged
14-LU.PA.A 46.57 2.84 52.13 41.01 3.42 0.56 4.53 2.32
Airborne Particle Abrasion & Silane &
Adhesive Non-Aged
15-LU.PSA.NA 87.26 1.98 91.13 83.38 9.30 1.48 12.19 6.41
Airborne Particle Abrasion & Silane &
Adhesive Aged
16-LU.PSA.A 52.61 2.58 57.67 47.56 4.32 0.65 5.59 3.05
VarseoSmile Crown Plus
Control Non-Aged 17-VS.C.NA 13.97 1.44 16.78 11.15 2.05 0.30 2.64 1.47
Control Aged 18-VS.C.A 10.00 1.26 12.48 7.52 1.65 0.27 2.17 1.12
Airborne Particle Abrasion Non-Aged 19-VS.P.NA 44.11 1.42 46.91 41.32 6.54 1.02 8.55 4.54
Airborne Particle Abrasion Aged 20-VS.P.A 44.57 2.41 49.30 39.85 3.93 0.54 4.98 2.88
silane Non-Aged 21-VS.S.NA 12.87 1.24 15.30 10.43 2.20 0.32 2.82 1.58
silane Aged 22-VS.S.A 14.53 1.87 18.19 10.87 1.66 0.23 2.11 1.21
Adhesive Non-Aged 23-VS.A.NA 24.94 2.42 29.68 20.19 2.17 0.34 2.83 1.52
Adhesive Aged 24-VS.A.A 19.83 2.26 24.27 15.39 1.87 0.26 2.38 1.36
Airborne Particle Abrasion & Silane NonAged
25-VS.PS.NA 41.16 1.22 43.55 38.76 7.13 1.06 9.20 5.06
Airborne Particle Abrasion & Silane Aged 26-VS.PS.A 44.40 1.34 47.04 41.77 6.99 1.05 9.04 4.93
silane & Adhesive Non-Aged 27-VS.SA.NA 22.86 2.66 28.08 17.63 1.82 0.27 2.35 1.30
silane & Adhesive Aged 28-VS.SA.A 21.87 2.47 26.71 17.04 1.89 0.27 2.41 1.36
Airborne Particle Abrasion & Adhesive
Non-Aged
29-VS.PA.NA 43.32 1.10 45.48 41.16 8.24 1.37 10.93 5.55
Airborne Particle Abrasion & Adhesive
Aged
30-VS.PA.A 46.03 1.28 48.54 43.51 7.59 1.18 9.91 5.28
135
Airborne Particle Abrasion & Silane &
Adhesive Non-Aged
31-VS.PSA.NA 44.42 1.26 46.89 41.94 7.48 1.05 9.54 5.41
Airborne Particle Abrasion & Silane &
Adhesive Aged
32-VS.PSA.A 45.24 1.51 48.20 42.28 6.32 0.96 8.20 4.44
Ceramic
Crown
Control Non-Aged 33-CC.C.NA 27.71 1.89 31.42 24.00 3.10 0.48 4.03 2.16
Control Aged 34-CC.C.A 18.51 1.48 21.41 15.61 2.64 0.41 3.45 1.84
Airborne Particle Abrasion Non-Aged 35-CC.P.NA 53.05 2.00 56.97 49.12 5.63 0.82 7.24 4.02
Airborne Particle Abrasion Aged 36-CC.P.A 43.58 2.42 48.33 38.83 3.69 0.63 4.93 2.44
silane Non-Aged 37-CC.S.NA 47.07 1.69 50.39 43.75 5.86 0.96 7.74 3.98
silane Aged 38-CC.S.A 41.94 2.45 46.74 37.14 3.58 0.60 4.75 2.40
Adhesive Non-Aged 39-CC.A.NA 48.53 2.15 52.75 44.31 4.73 0.76 6.22 3.25
Adhesive Aged 40-CC.A.A 40.28 1.99 44.18 36.38 4.25 0.68 5.59 2.91
Airborne Particle Abrasion and Silane
Non-Aged
41-CC.PS.NA 52.51 1.61 55.66 49.36 6.85 1.09 8.98 4.72
Airborne Particle Abrasion & Silane Aged 42-CC.PS.A 60.82 2.07 64.87 56.77 6.21 0.95 8.06 4.35
silane & Adhesive Non-Aged 43-CC.SA.NA 52.03 2.65 57.22 46.84 4.17 0.62 5.39 2.96
silane & Adhesive Aged 44-CC.SA.A 47.55 2.37 52.21 42.90 4.21 0.68 5.55 2.86
Airborne Particle Abrasion & Adhesive
Non-Aged
45-CC.PA.NA 59.37 1.66 62.64 56.11 7.57 1.08 9.70 5.45
Airborne Particle Abrasion & Adhesive
Aged
46-CC.PA.A 60.59 1.71 63.93 57.24 7.45 1.20 9.80 5.10
Airborne Particle Abrasion & Silane &
Adhesive Non-Aged
47-CC.PSA.NA 57.17 2.52 62.11 52.22 4.82 0.67 6.14 3.50
Airborne Particle Abrasion & Silane &
Adhesive Aged
48-CC.PSA.A 49.08 0.87 50.78 47.38 11.94 1.86 15.58 8.30
136
Weibull Characteristic Strength (��):
The Weibull characteristic strength is defined as the point at which 63.2% of specimens will
have failed. High characteristic strength values indicate low failure probability in comparison
with low characteristic strength values that indicate high failure probability.
Weibull modulus (�):
The Weibull modulus (�) presents the reliability of the composite-based materials on the µTBS
data. Weibull modulus with low values indicate failure distributions over large ranges of applied
forces, while those with high values are more likely to fail under a smaller range of applied
forces(163). Low Weibull modulus materials will not be as reliable as those with a high modulus
and will have a broad distribution of failure.
Probability of failure:
The Weibull analysis includes the presentation of a Weibull plot which is used to graph the
µTBS data (MPa) on the x-axis and the probability of failure (%) on the y-axis. The plot shows
the Weibull characteristic strength as a horizontal line to represent the 63.2% failure probability.
The Weibull modulus affects the steepness of each group based on the standard deviation of the
microtensile bond strength values.
Also, to determine whether the Weibull distribution Two-parameters are statistically
significantly different from one another, the likelihood contour plot was used. The x-axis
presents the characteristic strength, and the y-axis presents the Weibull modulus which both use
95 % confidence bounds.
In the likelihood contour plot, the two parameters appear as oval/circle shapes. The width of
these shapes is determined by the standard deviation of the characteristic strength. While the
length of these shapes is controlled by the standard deviation of the Weibull modulus. Once these
shapes intersect/overlap with one another, the two parameters are not statistically significant
from each other.
137
5.1.Materials:
5.1.1. Lava Ultimate:
The Two-parameters, Characteristic Strength (σ�) and Weibull Modulus (�) of Lava Ultimate
For aged and non-aged different surface treatments are presented inTable 101.
Table 101: Weibull Distribution (Two-Parameter) Characteristic Strength (σo) and Weibull Modulus (m) of Lava Ultimate
Overall, the highest Characteristic Strength in Lava Ultimate was found in non-aged treated with
Airborne Particle Abrasion & Adhesive (92.80 ±3.24MPa). Moreover, the highest Weibull
Modulus was also found at non-age treated with Airborne Particle abrasive & Silane & Adhesive
(9.30±1.48).
Surface Treatments �� Mean �� SD � Mean �SD
Non-aged
Control (C) 13.08 ± 0.75 3.64 ± 0.60
Airborne Particle Abrasion(P) 87.04 ± 3.23 5.59 ± 0.94
Silane(S) 46.25 ± 3.37 2.89 ± 0.46
Adhesive(A) 20.48 ± 1.25 3.48 ± 0.50
Airborne Particle Abrasion + Silane (PS) 86.67 ± 2.89 6.37 ± 0.90
silane + Adhesive (SA) 24.35 ± 1.79 2.83 ± 0.45
Airborne Particle Abrasion+ Adhesive (PA) 92.80 ± 3.24 6.04 ± 0.96
Airborne Particle Abrasion + Silane + Adhesive (PSA) 87.26 ± 1.98 9.30 ± 1.48
Aged
Control (C) 1.70 ± 0.48 1.50 ± 0.53
Airborne Particle Abrasion(P) 52.74 ± 2.61 4.22 ± 0.66
Silane(S) 19.80 ± 1.97 2.13 ± 0.30
Adhesive(A) 3.06 ± 0.54 1.17 ± 0.21
Airborne Particle Abrasion + Silane (PS) 60.08 ± 2.84 4.46 ± 0.69
silane + Adhesive (SA) 7.20 ± 0.82 1.83 ± 0.31
Airborne Particle Abrasion+ Adhesive (PA) 46.57 ± 2.84 3.42 ± 0.56
Airborne Particle Abrasion + Silane + Adhesive (PSA) 52.61 ± 2.58 4.32 ± 0.65
138
Weibull Characteristic Strength (σ�)
Non-aged: The Characteristic Strength value was highest when treated with PA (92.80 ±3.24
MPa), followed by PSA (87.26±1.98 MPa), then P (87.04±3.23 MPa), then PS (86.67 ± 2.89
MPa), then S (46.25± 3.37 MPa), then SA ( 24.35± 1.79 MPa)then A ( 20.48± 1.25 MPa). and
lastly C (13.08± 0.75 MPa). (PA>PSA>P>PS>S>SA>A>C)
Aged: The highest Characteristic Strength value was seen when treated with PS (60.08± 2.84
MPa), followed by P (52.74±± 2.61MPa), then PSA (52.61± 2.58 MPa), then PA (46.57± 2.84
MPa), then S (19.80± 1.97 MPa), then SA ( 7.20± 0.82 MPa)then A ( 3.06± 0.54 MPa). and
lastly C (1.70± 0.48 MPa). (PS>P>PSA>PA>S>SA>A>C)
Weibull Modulus (�)
Non-aged: The highest Weibull Modulus value was observed when treated with PSA (9.30±
1.48), followed by PS (6.378±0.90), then PA (6.04± 0.96), then S (5.59± 0.94), then C(3.64±
0.60), then A ( 3.48± 0.50)then S ( 2.89± 0.46). and lastly SA (2.83±0.45MPa).
(PSA>PS>PA>S>C>A>S>SA)
Aged: The highest Weibull Modulus value was seen when treated with PS(4.46± 0.69), followed
by PSA (4.32± 0.65), then P (4.22± 0.66), then PA (3.42 ± 0.56), then S (2.13 ± 0.30), then SA (
1.83± 0.31)then C ( 1.50± 0.53). and lastly A (1.17± 0.21). (PS>PSA>P>PA>S>SA>C>A)
Probability of Failure
Weibull plot:
The Weibull plot of Lava Ultimate with different surface treatments with the Weibull
characteristic strength at the failure probability of 63.2% is shown in (Table 101,Figure 64)
139
Figure 63: Weibull Plot (Plots of Failure Probabilities Against Micro Tensile Bond Strength) of Non-Aged Lava Ultimate
In the plot Figure 63, presented the effect of different surface treatments on µTBS of Lava
Ultimate material before aging. The highest characteristic strength value was observed in LU
Airborne Particle Abrasion +adhesive displayed the highest characteristic strength values,
followed by Airborne Particle Abrasion +silane + adhesive, then Airborne Particle Abrasion,
then Airborne Particle Abrasion + silane, then silane, then silane + adhesive, then adhesive and
lastly control. The highest Weibull Modulus value was observed when treated with Airborne
Particle Abrasion +silane + adhesive.
In plot Figure 64, presented the effect of different surface treatments on µTBS of Lava Ultimate
material after aging. The highest characteristic strength value was observed in LU treated with
Airborne Particle Abrasion +silane, followed by Airborne Particle Abrasion, then Airborne
Particle Abrasion +silane + adhesive, then Airborne Particle Abrasion +adhesive, then silane,
followed by silane + adhesive, then adhesive, and lastly control. The higher standard deviation of
the µTBS values impacted the shape of the slope (Weibull modulus) leading to scattered data
causing a shallow slope. The highest Weibull Modulus value was seen when treated with
Airborne Particle Abrasion +silane.
140
Figure 64: Weibull Plot (Plots of Failure Probabilities Against Micro Tensile Bond Strength) of Aged Lava Ultimate
Contour plot:
The likelihood contour plot of the Lava Ultimate for different surface treatments of non-aged is
shown in Figure 65, while the Aged is in Figure 66.
141
Figure 65: Likehood Contour Plot of Lava Ultimate Non-Aged
On the plot of the non-aged (Figure 65), the control and silane don't intersect with any of the
other surface treatments, so they are significantly different from all other treatments. the
adhesive and the silane + adhesive intersect each other, indicating no statistically significant
difference. All the treatments including Airborne Particle abrasions intersect with each other,
indicating no statistically significant difference. except the Airborne Particle abrasions+ adhesive
and Airborne Particle abrasions+ silane+ adhesive which don’t intersect indicating a statistically
significant difference. The highest overlap was observed between Airborne Particle abrasions
and Airborne Particle abrasions+ silane.
On the other plot graph for Aged (Figure 66). Shows that the adhesive and silane+ Adhesive the
only two do not intersect with any of the other surface treatments, which indicates a statistically
significant difference. There is no statistically significant difference between the adhesive and
the control. Also, there is no statistically significant difference between all the treatments
including the Airborne Particle abrasions. The highest overlap was observed between Airborne
Particle abrasions and Airborne Particle abrasions+ silane+ adhesive.
142
Figure 66: Likelihood Contour Plot of Lava Ultimate Aged
143
5.1.2. VarseoSmile Crown Plus:
The Two-parameters, Characteristic Strength (σ�) and Weibull Modulus (�) of VarseoSmile
Crown Plus For aged and non-aged different surface treatments are presented in Table 102
Table 102: Weibull Distribution (Two-Parameter) Characteristic Strength (σo) and Weibull Modulus (m) of VarseoSmile Crown
Plus
Overall, the highest Characteristic Strength in VarseoSmile Crown Plus was found in Aged
treated with Airborne Particle Abrasion + Adhesive (46.03±1.28MPa). Moreover, the highest
Weibull Modulus was found at non-age treated with Airborne Particle abrasive+ Adhesive
(8.24±1.37).
Surface Treatment �� Mean �� SD �
Mean
�SD
Non-aged
Control (C) 13.79 ± 1.44 2.05 ± 0.30
Airborne Particle Abrasion(P) 44.11 ± 1.42 6.54 ± 1.02
Silane(S) 12.87 ± 1.24 2.20 ± 0.32
Adhesive(A) 24.94 ± 2.42 2.17 ± 0.34
Airborne Particle Abrasion + Silane (PS) 41.16 ± 1.22 7.13 ± 1.06
silane + Adhesive (SA) 22.86 ± 2.66 1.82 ± 0.27
Airborne Particle Abrasion+ Adhesive (PA) 43.32 ± 1.10 8.24 ± 1.37
Airborne Particle Abrasion + Silane + Adhesive (PSA) 44.42 ± 1.26 7.48 ± 1.05
Aged
Control (C) 10.00 ± 1.26 1.65 ± 0.27
Airborne Particle Abrasion(P) 44 57 ± 2.41 3.93 ± 0.54
Silane(S) 14.53 ± 1.87 1.66 ± 0.23
Adhesive(A) 19.83 ± 2.26 1.87 ± 0.26
Airborne Particle Abrasion + Silane (PS) 44.40 ± 1.34 6.99 ± 1.05
silane + Adhesive (SA) 21.87 ± 2.47 1.89 ± 0.27
Airborne Particle Abrasion+ Adhesive (PA) 46.03 ± 1.28 7.59 ± 1.18
Airborne Particle Abrasion + Silane + Adhesive (PSA) 45.24 ± 1.51 6.32 ± 0.96
144
Weibull Characteristic Strength (σ�)
Non-aged: The Characteristic Strength value was highest when treated with PSA (44.42±1.26
MPa), followed by P (44.11±1.42 MPa), then PA (43.32±1.10 MPa), then PS (41.16± 1.22 MPa),
then A (24.94± 2.42 MPa), then SA (22.86± 2.66 MPa)then C( 13.79± 1.44 MPa). and lastly S
(12.87± 1.24 MPa). (PSA>P>PA>PS>A>SA>C>S)
Aged: The highest Characteristic Strength value was seen when treated with PA(46.03± 1.28
MPa), followed by PSA (45.24± 1.51 MPa), then P (44 57± 2.41 MPa), then PS (44.40± 1.34
MPa), then SA (21.87± 2.47 MPa), then A ( 19.83± 2.26 MPa)then S ( 14.53± 1.87 MPa). and
lastly C (10.00± 1.26 MPa). (PA>PSA>P>PS>SA>A>S>C)
Weibull Modulus (�)
Non-aged: The highest Weibull Modulus value was observed when treated with PA (8.24±
1.37), followed by PSA (7.48±1.05), then PS (7.13± 1.06), then P (6.54± 1.02), then S(2.20±
0.32), then A ( 2.17± 0.34), then C( 2.05± 0.30). and lastly SA (1.82±0.27).
(PA>PSA>PS>P>S>A>C>SA)
Aged: The highest Weibull Modulus value was seen when treated with PA (7.59± 1.18),
followed by PS (6.99±1.05), then PSA (6.32 ± 0.96), then P (3.93a± 0.54), then SA (1.89± 0.27),
then A ( 1.87± 0.26)then S ( 1.66± 0.23). and lastly C (1.65± 0.27).
(PA>PS>PSA>P>SA>A>S>C)
Probability of Failure
Weibull plot:
The Weibull plot of VarseoSmile Crown Plus with different surface treatments with the Weibull
characteristic strength at the failure probability of 63.2% is shown in (Figure 67,Figure 68)
145
Figure 67: Weibull Plot (Plots of Failure Probabilities Against Micro Tensile Bond Strength) of Non-Aged VarseoSmile Crown
Plus
In the plot (Figure 67) the Non-age VarseoSmile Crown Plus treated with Airborne Particle
Abrasion +adhesive + silane displayed the highest characteristic strength values, followed by
Airborne Particle Abrasion, then Airborne Particle Abrasion+ Adhesive, then Airborne Particle
Abrasion + silane, then Adhesive, then silane + adhesive, then control and lastly Silane. The
highest Weibull Modulus value was observed when treated with Airborne Particle Abrasion+
Adhesive.
In plot (Figure 68) the Aged VarseoSmile Crown Plus treated with Airborne Particle Abrasion
+Adhesive, followed by Airborne Particle Abrasion+ silane + adhesive, then Airborne Particle
Abrasion, then Airborne Particle Abrasion + silane, then silane + adhesive, followed by
Adhesive, then silane, and lastly control. The higher standard deviation of the µTBS values
impacted the shape of the slope (Weibull modulus) leading to scattered data causing a shallow
slope. The highest Weibull Modulus value was seen when treated with Airborne Particle
Abrasion+ Adhesive.
146
Figure 68: Weibull Plot (Plots of Failure Probabilities Against Micro Tensile Bond Strength) of Aged VarseoSmile Crown Plus
Contour plot:
The likelihood contour plot of the VarseoSmile Crown Plus for different surface treatments of
non-aged is shown in(Figure 69), while the Aged is in(Figure 70).
Figure 69: Likelihood Contour Plot of VarseoSmile Crown Plus Non-Aged
147
On the plot of the non-aged (Figure 69), the control and silane intersect with each other, so they
are not statistically significantly different from each other. the adhesive and the silane + adhesive
intersect each other, indicating no statistically significant difference. All the treatments including
Airborne Particle abrasions intersect with each other, indicating no statistically significant
difference. The surface treatment doesn't interact with each other which means there is a
Statistically significant difference between each other. Such as between all treatments including
Airborne Particle abrasions and control, silane, adhesive, and silane + adhesive there are
statistically significant differences. The highest overlap was observed between P and PSA.
The other plot graph for after aging (Figure 70). Shows that there's no significant difference
between (C&S), (S&A&SA) ,(PSA&P), (PSA & PA & PS). There is a significant difference
between ( P& PA, PS) and (C& SA, A). and the highest Weibull modulus was shown in
Airborne Particle abrasions+ silane. The highest overlap was observed between A and SA.
Figure 70: Likelihood Contour Plot of VarseoSmile Crown Plus Aged
148
5.1.3. Ceramic Crown:
The Two-parameters, Characteristic Strength (σ�) and Weibull Modulus (�) of Ceramic crown
For aged and non-aged different surface treatments are presented in Table 103
Table 103: Weibull Distribution (Two-Parameter) Characteristic Strength (σo) and Weibull Modulus (m) of Ceramic crown
Overall, the highest Characteristic Strength Ceramic crown was found in Aged treated with
Airborne Particle Abrasion + Silane (60.82±2.07 MPa). Moreover, the highest Weibull Modulus
was found at Aged treated with Airborne Particle abrasive+ silane+ Adhesive (11.94±1.86).
Surface Treatment
��
Mean
�� SD
�
Mean
�SD
Non-aged
Control (C) 27.71 ± 1.89 3.10 ± 0.48
Airborne Particle Abrasion(P) 53.05 ± 2.00 5.63 ± 0.82
Silane(S) 47.07 ± 1.69 5.86 ± 0.96
Adhesive(A) 48.53 ± 2.15 4.73 ± 0.76
Airborne Particle Abrasion + Silane (PS) 52.51 ± 1.61 6.85 ± 1.09
silane + Adhesive (SA) 52.03 ± 2.65 4.17 ± 0.62
Airborne Particle Abrasion+ Adhesive (PA) 59.37 ± 1.66 7.57 ± 1.08
Airborne Particle Abrasion + Silane + Adhesive (PSA) 57.17 ± 2.52 4.82 ± 0.67
Aged
Control (C) 18.51 ± 1.48 2.64 ± 0.41
Airborne Particle Abrasion(P) 43.58 ± 2.42 3.69 ± 0.63
Silane(S) 41.94 ± 2.45 3.58 ± 0.60
Adhesive(A) 40.28 ± 1.99 4.25 ± 0.68
Airborne Particle Abrasion + Silane (PS) 60.82 ± 2.07 6.21 ± 0.95
silane + Adhesive (SA) 47.55 ± 2.37 4.21 ± 0.68
Airborne Particle Abrasion+ Adhesive (PA) 60.59 ± 1.71 7.45 ± 1.20
Airborne Particle Abrasion + Silane + Adhesive (PSA) 49.08 ± 0.87 11.94 ± 1.86
149
Weibull Characteristic Strength (σ�)
Non-aged: The Characteristic Strength value was highest when treated with PA (59.37±1.66
MPa), followed by PSA (57.17±2.52 MPa), then P (53.05±2.00 MPa), then PS (52.51± 1.61
MPa), then SA (52.03± 2.65 MPa), then A (48.53± 2.15 MPa), then S(47.07± 1.69 MPa). and
lastly C (27.71± 1.89 MPa). (PA>PSA>P>PS>SA>A>S>C)
Aged: The highest Characteristic Strength value was seen when treated with PS (60.82± 2.07
MPa), followed by PA (60.59± 1.71 MPa), then PSA (49.08± 0.87 MPa), then SA (47.55± 2.37
MPa), then P (43.58± 2.42 MPa), then S (41.94± 2.45 MPa), then A (40.28± 1.99 MPa). and
lastly C (18.51± 1.48 MPa). (PS>PA>PSA>SA>P>S>A>C)
Weibull Modulus (�)
Non-aged: The highest Weibull Modulus value was observed when treated with PA (7.57±
1.08), and lowest C (3.10±0.48). (PA>PS>S>P>PSA>A>SA>C)
Aged: The highest Weibull Modulus value was seen when treated with PSA (11.94a± 1.86), and
lowest C (2.64± 0.41). (PSA>PA>PS>A>SA>P>S>C)
Probability of Failure
Weibull plot:
The Weibull plot of Ceramic Crown with different surface treatments with the Weibull
characteristic strength at the failure probability of 63.2% is shown in (Figure 71,Figure 72)
150
Figure 71: Weibull Plot (Plots of Failure Probabilities Against Micro Tensile Bond Strength) of Non-Aged Ceramic Crown
In the plot (Figure 71) the Non-age Ceramic crown treated with Airborne Particle Abrasion
+adhesive displayed the highest characteristic strength values, followed by Airborne Particle
Abrasion + silane + adhesive, then Airborne Particle Abrasion, then Airborne Particle Abrasion
+ silane, then silane + adhesive, then adhesive, then Silane and lastly control. The highest
Weibull Modulus value was observed when treated with PA.
In plot (Figure 72) the Aged treated with Airborne Particle Abrasion + silane, followed by
Airborne Particle Abrasion+ adhesive, then Airborne Particle Abrasion+ silane+ adhesive, then
silane + adhesive, then Airborne Particle Abrasion, followed by silane, then Adhesive, and lastly
control. The highest Weibull Modulus value was seen when treated with PSA. The higher
standard deviation of the µTBS values impacted the shape of the slope (Weibull modulus)
leading to scattered data causing a shallow slope.
151
Figure 72: Weibull Plot (Plots of Failure Probabilities Against Micro Tensile Bond Strength) of Aged Ceramic Crown
Contour plot:
The likelihood contour plot of the Ceramic Crown for different surface treatments of non-aged is
shown in(Figure 73), while the Aged is in (Figure 74).
On the plot of the non-aged (Figure 73), the control group is Statistically significant for all other.
the Airborne Particle abrasions intersect with (A,S,SA,PA,PS,PSA) indicating no statistically
significant difference. The static significant different was found between (PA and PS,S,A,SA)
and between (PSA and S). The highest overlap was observed between P and PS.
While in other plot graphs for after aging (Figure 74). Shows that there's no significant
difference between (PS & PA), (P&S&A, SA) Moreover, There is a significant difference
between control and all the groups and PSA and all the groups. and the highest Weibull modulus
was shown in Airborne Particle abrasions + silane + adhesive. The highest overlap was observed
between A and S.
152
Figure 73: Likelihood Contour Plot of Ceramic Crown Non-Aged
Figure 74: Likelihood Contour Plot of Ceramic Crown Aged
153
5.2.Surface Treatment:
5.2.1. Control(C):
The Two-parameters, Characteristic Strength (σ�) and Weibull Modulus (�) at the control
surface treatment of the tested materials in Non-Aged and Aged are presented in Table 104.
Table 104: Weibull distribution ( Two Parameters) Characteristic Strength ( ��) and Weibull Modulus (m) of Control Treatment
Overall, the highest Characteristic Strength in the control was found in the Non-Aged ceramic
crown (27.71±1.89 MPa). Moreover, the highest Weibull Modulus was also found in Non-Aged
Lava Ultimate (3.64±0.60 MPa).
Weibull Characteristic Strength (σ�)
Non-Aged: The Characteristic Strength value was highest in Ceramic Crown (27.71±1.89 MPa),
followed by VarseoSmile Crown Plus (13.79±1.44 MPa), and lastly Lava Ultimate (13.08±0.75
MPa). (CC>VS>LU)
Aged: The highest Characteristic Strength value was seen in Ceramic Crown (18.51±1.48 MPa),
followed by VarseoSmile Crown Plus (10.00±1.26 MPa), and lastly Lava Ultimate (1.70±0.48
MPa). (CC>VS>LU)
Material Aging
��
Mean
�� SD
�
Mean
�SD
Lava Ultimate
Non -Aged 13.08 ± 0.75 3.64 ± 0.60
Aged 1.70 ± 0.48 1.50 ± 0.53
VarseoSmile Crown Plus Non -Aged 13.79 ± 1.44 2.05 ± 0.30
Aged 10.00 ± 1.26 1.65 ± 0.27
Ceramic Crown Non -Aged 27.71 ± 1.89 3.10 ± 0.48
Aged 18.51 ± 1.48 2.64 ± 0.41
154
Weibull Modulus (�)
Non-Aged: The highest Weibull Modulus value for Non-Aged was observed in Lava Ultimate
(3.64±0.60), followed by Ceramic Crown (3.10±0.48), and lastly VarseoSmile Crown Plus
(2.05±0.30). (LU>CC>VS)
Aged: The highest Weibull Modulus value for Aged was seen in Ceramic Crown (2.64±0.41),
followed by VarseoSmile Crown Plus (1.65 ±0.27), and lastly Lava Ultimate (1.50±0.53).
(CC>VS>LU)
Probability of Failure
Weibull plot:
The Weibull plot for the tested materials in both Aging at Control surface treatment with the
Weibull characteristic strength at the failure probability of 63.2% is shown in Figure 75
Figure 75: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Control
155
In the plot, the Non-Aged at control displayed the highest characteristic strength values with
Ceramic Crown, followed by VarseoSmile Crown Plus, and lastly Lava Ultimate. The highest
Weibull Modulus value for non-aged was observed in Lava Ultimate.
Whereas the Aged at control were lower with Lava Ultimate, followed by VarseoSmile Crown
Plus, and lastly Ceramic Crown. The highest Weibull Modulus value for Aged was seen in
Ceramic Crown. The higher standard deviation of the µTBS values impacted the shape of the
slope (Weibull modulus) leading to scattered data causing a shallow slope.
Contour plot:
The likelihood contour plot for the tested materials in different aging at Control surface treatment
is shown in Figure 76
Figure 76: Likelihood Contour Plot (Control)
On the plot, the Lava Ultimate, Ceramic Crown doesn't intersect, indicating a statistically
significant difference before and after aging. On the plot, VarseoSmile Crown Plus intersects
which indicates no statistically significant difference before and after aging. whereas the Aged
156
Ceramic Crown intersects with Non-Aged VarseoSmile Crown Plus indicating no statistically
significant difference.
5.2.2. Airborne Particle Abrasion (P):
The Two-parameters, Characteristic Strength (σ�) and Weibull Modulus (�) at the Airborne
Particles Abrasion surface treatment of the tested materials in Non-Aged and Aged are presented
in Table 105. Table 105
Table 105: Weibull Distribution (Two Parameters) Characteristic Strength (��) and Weibull Modulus (m) of Airborne Particle
Abrasion treatment
Overall, the highest Characteristic Strength in the Airborne Particle abrasion was found in the
Non-Aged Lava Ultimate (87.04±3.23 MPa). Moreover, the highest Weibull Modulus was also
found in Non-Aged VarseoSmile Crown Plus(6.54±1.02 MPa).
Weibull Characteristic Strength (σ�)
Non-Aged: The Characteristic Strength value was highest in Lava Ultimate (87.04± 3.23 MPa),
followed by Ceramic Crown (53.05± 2.00 MPa), and lastly VarseoSmile Crown Plus (44.11±
1.42 MPa). (LU>CC>VS)
Aged: The highest Characteristic Strength value was seen in Lava Ultimate (52.74± 2.61 MPa),
followed by VarseoSmile Crown Plus (44 57±± 2.41 MPa), and lastly Ceramic Crown
(43.58±2.42 MPa). (LU>VS>CC)
Weibull Modulus (�)
Non-Aged: The highest Weibull Modulus value for Non-Aged was observed in Lava Ultimate
(3.64±0.60), followed by Ceramic Crown (3.10±0.48), and lastly VarseoSmile Crown Plus
(2.05±0.30). (LU>CC>VS)
157
Aged: The highest Weibull Modulus value for Aged was seen in Ceramic Crown (2.64±0.41),
followed by VarseoSmile Crown Plus (1.65 ±0.27), and lastly Lava Ultimate (1.50±0.53).
(CC>VS>LU)
Probability of Failure
Weibull plot:
The Weibull plot for the tested materials in both Aging at Airborne Particle Abrasion surface
treatment with the Weibull characteristic strength at the failure probability of 63.2% is shown in
Figure 77
Figure 77: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Airborne Particle Abrasion
In the plot, the Non-Aged at control displayed the highest characteristic strength values with
Lava Ultimate, followed by Ceramic Crown, and lastly VarseoSmile Crown Plus. The highest
Weibull Modulus value for Non-Aged was observed in Lava Ultimate.
Whereas the Aged at Airborne Particle abrasion was lower with Ceramic Crown followed by
VarseoSmile Crown Plus, and lastly Lava Ultimate. The highest Weibull Modulus value for
158
Aged was seen in Ceramic Crown. The higher standard deviation of the µTBS values impacted
the shape of the slope (Weibull modulus) leading to scattered data causing a shallow slope.
Contour plot:
The likelihood contour plot for the tested materials in different aging at Airborne Particle
Abrasion surface treatment is shown in Figure 78
Figure 78: Likelihood Contour Plot (Airborne Particle Abrasion)
On the plot, the Lava Ultimate, Ceramic Crown doesn't intersect, indicating a statistically
significant difference before and after aging. On the plot, VarseoSmile Crown Plus intersects
which indicates no statistically significant difference before and after aging. whereas the Aged
Ceramic Crown intersects with Non-Aged, Aged VarseoSmile Crown Plus, and Aged Lava
Ultimate indicating no statistically significant difference. The highest overlap was observed
between (VS.A)and (CC.A).
159
5.2.3. Silane(S):
The Two-parameters, Characteristic Strength (σ�) and Weibull Modulus (�) at the Silane
surface treatment of the tested materials in Non-Aged and Aged are presented in Table 106
Table 106: Weibull Distribution (Two Parameters) Characteristic Strength (��) and Weibull Modulus (m) of Silane Treatment
Overall, the highest Characteristic Strength and Weibull Modulus in the Silane were found in the
Non-Aged Ceramic Crown (47.07±1.69 MPa) (5.86±0.96) respectively.
Weibull Characteristic Strength (σ�)
Non-Aged: The Characteristic Strength value was highest in Ceramic Crown (47.07±1.69 MPa),
followed by Lava Ultimate (46.25± 3.37 MPa), and lastly VarseoSmile Crown Plus (12.87± 1.24
MPa). (CC>LU>VS)
Aged: The highest Characteristic Strength value was seen in Ceramic Crown (41.94± 2.45 MPa),
followed by Lava Ultimate (19.80±1.97 MPa), and lastly VarseoSmile Crown Plus (14.53±1.87
MPa). (CC>LU>VS)
Material Aging
��
Mean
�� SD
�
Mean
�SD
Lava Ultimate
Non -Aged 46.25 ± 3.37 2.89 ± 0.46
Aged 19.80 ± 1.97 2.13 ± 0.30
VarseoSmile Crown Plus Non -Aged 12.87 ± 1.24 2.20 ± 0.32
Aged 14.53 ± 1.87 1.66 ± 0.23
Ceramic Crown Non -Aged 47.07 ± 1.69 5.86 ± 0.96
Aged 41.94 ± 2.45 3.58 ± 0.60
160
Weibull Modulus (�)
Non-Aged: The highest Weibull Modulus value for Non-Aged was observed in Ceramic Crown
(5.86±0.96), followed by Lava Ultimate (2.89±0.46), and lastly VarseoSmile Crown Plus
(2.20±0.32). (CC>LU>VS)
Aged: The highest Weibull Modulus value for Aged was seen in Ceramic Crown (3.58±0.60),
followed by Lava Ultimate (2.13±0.30), and lastly VarseoSmile Crown Plus (1.66±0.23).
(CC>LU>VS)
Probability of Failure
Weibull plot:
The Weibull plot for the tested materials in both Aging at Airborne Particle Abrasion surface
treatment with the Weibull characteristic strength at the failure probability of 63.2% is shown in
Figure 79Figure 77
Figure 79: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Silane
In the plot, the Non-Aged at control displayed the highest characteristic strength values with
Ceramic Crown, followed by Lava Ultimate, and lastly VarseoSmile Crown Plus. The highest
Weibull Modulus value for Non-Aged was observed in Ceramic Crown.
161
Whereas the Aged at Airborne Particle abrasion was lower with VarseoSmile Crown Plus
followed by Lava Ultimate, and lastly Ceramic Crown. The highest Weibull Modulus value for
Aged was seen in Ceramic Crown The higher standard deviation of the µTBS values impacted
the shape of the slope (Weibull modulus) leading to scattered data causing a shallow slope.
Contour plot:
The likelihood contour plot for the tested materials in different aging at silane surface treatment
is shown in Figure 80
Figure 80: Likelihood Contour Plot (Silane)
On the plot, the Lava Ultimate doesn't intersect, indicating a statistically significant difference
before and after aging. On the plot, VarseoSmile Crown Plus, Ceramic Crown intersects
which indicates no statistically significant difference before and after aging. The highest overlap
was observed between (CC.A) and (LU.NA).
162
5.2.4. Adhesive(A):
The Two-parameters, Characteristic Strength (σ�) and Weibull Modulus (�) at the Adhesive
surface treatment of the tested materials in Non-Aged and Aged are presented in Table 107.
Table 107: Weibull Distribution (Two Parameters) Characteristic Strength (�o) and Weibull Modulus (m) of Adhesive treatment
Overall, the highest Characteristic Strength and Weibull Modulus in the Adhesive were found in
the Non-Aged Ceramic Crown (48.53±2.15 MPa) (4.73±0.76) respectively.
Weibull Characteristic Strength (σ�)
Non-Aged: The Characteristic Strength value was highest in Ceramic Crown (47.07±1.69 MPa),
followed by Lava Ultimate (46.25± 3.37 MPa), and lastly VarseoSmile Crown Plus (12.87± 1.24
MPa). (CC>LU>VS)
Aged: The highest Characteristic Strength value was seen in Ceramic Crown (41.94± 2.45 MPa),
followed by Lava Ultimate (19.80±1.97 MPa), and lastly VarseoSmile Crown Plus (14.53±1.87
MPa). (CC>LU>VS)
Weibull Modulus (�)
Non-Aged: The highest Weibull Modulus value for Non-Aged was observed in Ceramic Crown
(5.86±0.96), followed by Lava Ultimate (2.89±0.46), and lastly VarseoSmile Crown Plus
(2.20±0.32). (CC>LU>VS)
Material Aging
��
Mean
�� SD
�
Mean
�SD
Lava Ultimate
Non -Aged 20.48 ±20.48 3.48 ± 0.50
Aged 3.06 ±3.06 1.17 ± 0.21
VarseoSmile Crown Plus Non -Aged 24.94 ±2.42 2.17 ±0.34
Aged 19.83 ±2.26 1.87 ±0.26
Ceramic Crown Non -Aged 48.53 ± 2.15 4.73 ± 0.76
Aged 40.28 ± 1.99 4.25 ± 0.68
163
Aged: The highest Weibull Modulus value for Aged was seen in Ceramic Crown (3.58±0.60),
followed by Lava Ultimate (2.13±0.30), and lastly VarseoSmile Crown Plus (1.66±0.23).
(CC>VS>LU)
Probability of Failure
Weibull plot:
The Weibull plot for the tested materials in both Aging at Adhesive surface treatment with the
Weibull characteristic strength at the failure probability of 63.2% is shown in Figure 81
Figure 81: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Adhesive
In the plot, the Non-Aged and Aged at Adhesive displayed the highest characteristic strength
values with Ceramic Crown, followed by Lava Ultimate, and lastly VarseoSmile Crown Plus.
The highest Weibull Modulus value for Non-Aged and Aged was observed in Ceramic Crown.
The higher standard deviation of the µTBS values impacted the shape of the slope (Weibull
modulus) leading to scattered data causing a shallow slope.
Contour plot:
The likelihood contour plot for the tested materials in different aging at Adhesive surface
treatment is shown in Figure 82.
164
Figure 82: Likelihood Contour Plot (Adhesive)
On the plot, the Lava Ultimate doesn't intersect, indicating a statistically significant difference
before and after aging. On the plot, VarseoSmile Crown Plus, Ceramic Crown intersects
which indicates no statistically significant difference before and after aging.the highest overlap
was observed between (VS.A) and (VS.NA).
5.2.5. Airborne Particle Abrasion + Silane (PS):
The Two-parameters, Characteristic Strength (σ�) and Weibull Modulus (�) at the Airborne
Particle Abrasion +Silane surface treatment of the tested materials in Non-Aged and Aged are
presented in Table 108
Table 108: Weibull Distribution (Two Parameters) Characteristic Strength (�o) and Weibull Modulus (m) of Airborne Particle
Abrasion+ Silane Treatment
Material Aging
��
Mean
�� SD
�
Mean
�SD
Lava Ultimate
Non -Aged 86.67 ± 2.89 6.37 ± 0.90
Aged 60.08 ± 2.84 4.46 ± 0.69
VarseoSmile Crown Plus Non -Aged 41.16 ± 1.22 7.13 ± 1.06
Aged 44.40 ± 1.34 6.99 ± 1.05
Ceramic Crown Non -Aged 52.51 ± 1.61 6.85 ± 1.09
Aged 60.82 ± 2.07 6.21 ± 0.95
165
Overall, the highest Characteristic Strength in the (PS) was found in the Non-Aged Lava
Ultimate (86.67±2.89 MPa). Moreover, the highest Weibull Modulus was also found in NonAged VarseoSmile Crown Plus (7.13±1.06 MPa).
Weibull Characteristic Strength (σ�)
Non-Aged: The Characteristic Strength value was highest in Lava Ultimate (86.67±2.89 MPa),
followed by Ceramic Crown (52.51± 1.61 MPa), and lastly VarseoSmile Crown Plus (41.16±
1.22 MPa). (LU>CC>VS)
Aged: The highest Characteristic Strength value was seen in Ceramic Crown (60.82± 2.07 MPa),
followed by Lava Ultimate (60.08±2.84 MPa), and lastly VarseoSmile Crown Plus (44.40±1.34
MPa). (CC>LU>VS)
Weibull Modulus (�)
Non-Aged: The highest Weibull Modulus value for Non-Aged was observed in VarseoSmile
Crown Plus (7.13±1.06), followed by Ceramic Crown (6.85±1.09), and lastly Lava Ultimate
(6.37±0.90). (VS>CC>LU)
Aged: The highest Weibull Modulus value for Aged was seen in VarseoSmile Crown Plus
(6.99±1.05), followed by Ceramic Crown (6.21±0.95), and lastly Lava Ultimate (4.46±0.69).
(VS>CC>LU)
Probability of Failure
Weibull plot:
The Weibull plot for the tested materials in both Aging at Airborne Particle Abrasion+ Silane
surface treatment with the Weibull characteristic strength at the failure probability of 63.2% is
shown in Figure 83.
166
Figure 83: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Airborne Particle Abrasion+ Silane
In the plot, the Non-Aged at (PS) displayed the highest characteristic strength values with Lava
Ultimate, followed by Ceramic Crown, and lastly VarseoSmile Crown Plus. The highest Weibull
Modulus value for Non-Aged was observed in VarseoSmile Crown Plus.
Whereas the Aged at (PS) was lower with VarseoSmile Crown Plus followed by Lava Ultimate,
and lastly Ceramic Crown. The highest Weibull Modulus value for Aged was seen in
VarseoSmile Crown Plus The higher standard deviation of the µTBS values impacted the shape
of the slope (Weibull modulus) leading to scattered data causing a shallow slope.
Contour plot:
The likelihood contour plot for the tested materials in different aging at (PS) surface treatment is
shown in Figure 84.
167
Figure 84: Likelihood Contour Plot (Airborne Particle Abrasion+Silane)
On the plot, the Lava Ultimate, Ceramic Crown doesn’t intersect, indicating a statistically
significant difference before and after aging. On the plot, VarseoSmile Crown Plus intersects
which indicates no statistically significant difference before and after aging. The highest overlap
was observed between (LU.A) and (CC.A)
168
5.2.6. Silane + Adhesive (SA):
The Two-parameters, Characteristic Strength (σ�) and Weibull Modulus (�) at the silane +
Adhesive surface treatment of the tested materials in Non-Aged and Aged are presented in Table
109.
Table 109: Weibull Distribution (Two Parameters) Characteristic Strength (�o) and Weibull Modulus (m) of Silane+ Adhesive
Treatment
Overall, the highest Characteristic Strength in the (SA) was found in the Non-Aged Ceramic
Crown (52.03±2.65 MPa). Moreover, the highest Weibull Modulus was also found in Aged
Ceramic Crown (4.21±0.68).
Weibull Characteristic Strength (σ�)
Non-Aged: The Characteristic Strength value was highest in Ceramic Crown (52.03±2.65 MPa),
followed by VarseoSmile Crown Plus (22.86± 2.66 MPa), and lastly Lava Ultimate (24.35± 1.79
MPa). (CC>VS>LU)
Aged: The highest Characteristic Strength value was seen in Ceramic Crown (60.59± 1.71 MPa),
followed by VarseoSmile Crown Plus (21.87±2.47 MPa), and lastly Lava Ultimate (7.20±0.82
MPa). (CC>VS>LU)
Material Aging
��
Mean
�� SD
�
Mean
�SD
Lava Ultimate
Non -Aged 24.35 ± 1.79 2.83 ± 0.45
Aged 7.20 ± 0.82 1.83 ± 0.31
VarseoSmile Crown Plus Non -Aged 22.86 ± 2.66 1.82 ± 0.27
Aged 21.87 ± 2.47 1.89 ± 0.27
Ceramic Crown Non -Aged 52.03 ± 2.65 4.17 ± 0.62
Aged 60.59 ± 1.71 7.45 ± 1.20
169
Weibull Modulus (�)
Non-Aged: The highest Weibull Modulus value for Non-Aged was observed in Ceramic Crown
(4.17±0.62), followed by Lava Ultimate (2.83±0.45), and lastly VarseoSmile Crown Plus
(1.82±0.31). (CC>LU>VS)
Aged: The maximum Weibull Modulus value for Aged was seen in Ceramic Crown (4.21±0.68),
followed by VarseoSmile Crown Plus (1.89±0.27), and lastly Lava Ultimate (1.83±0.31).
(CC>VS>LU)
Probability of Failure
Weibull plot:
The Weibull plot for the tested materials in both Aging at Silane+ Adhesive surface treatment
with the Weibull characteristic strength at the failure probability of 63.2% is shown in Figure 85.
Figure 85: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Silane+ Adhesive
In the plot, the Non-Aged and Aged at (SA) displayed the highest characteristic strength values
with Ceramic Crown, followed by VarseoSmile Crown Plus Ceramic Crown, and lastly Lava
Ultimate. The highest Weibull Modulus value for Non-Aged and Aged was observed in
170
Ceramic Crown. The higher standard deviation of the µTBS values impacted the shape of the
slope (Weibull modulus) leading to scattered data causing a shallow slope.
Contour plot:
The likelihood contour plot for the tested materials in different aging at (SA) surface treatment is
shown in Figure 86. Figure 86: Likelihood Contour Plot (Silane+ Adhesive)
On the plot, the Lava Ultimate doesn’t intersect, indicating a statistically significant difference
before and after aging. On the plot, VarseoSmile Crown Plus, Ceramic Crown intersects
which indicates no statistically significant difference before and after aging. The highest overlap
was observed between (VS.A) and (VS.NA).
171
5.2.7. Airborne Particle Abrasion + Adhesive (PA):
The Two-parameters, Characteristic Strength (σ�) and Weibull Modulus (�) at the Airborne
Particle Abrasion+ Adhesive surface treatment of the tested materials in Non-Aged and Aged
are presented in Table 110. Table 110: Weibull Distribution (Two Parameters) Characteristic Strength (�o) and Weibull Modulus (m) of Airborne Particle
Abrasion+ Adhesive treatment
Overall, the highest Characteristic Strength in the (PA) was found in the Non-Aged Lava
Ultimate (92.80±3.24 MPa). Moreover, the highest Weibull Modulus was also found in NonAged VarseoSmile Crown Plus (8.24±1.37).
Weibull Characteristic Strength (σ�)
Non-Aged: The Characteristic Strength value was highest in Lava Ultimate (59.37±3.24 MPa),
followed by Ceramic Crown (59.37± 1.66 MPa), and lastly VarseoSmile Crown Plus (43.32±
1.10 MPa). (LU>CC>VS)
Aged: The highest Characteristic Strength value was seen in Ceramic Crown (60.59± 1.71 MPa),
followed by Lava Ultimate (46.57±2.84 MPa), and lastly VarseoSmile Crown Plus (46.03±1.28
MPa). (CC>LU>VS)
Weibull Modulus (�)
Material Aging
��
Mean
�� SD
�
Mean
�SD
Lava Ultimate
Non -Aged 92.80 ± 3.24 6.04 ± 0.96
Aged 46.57 ± 2.84 3.42 ± 0.56
VarseoSmile Crown Plus Non -Aged 43.32 ± 1.10 8.24 ± 1.37
Aged 46.03 ± 1.28 7.59 ± 1.18
Ceramic Crown Non -Aged 59.37 ± 1.66 7.57 ± 1.08
Aged 60.59 ± 1.71 7.45 ± 1.20
172
Non-Aged: The highest Weibull Modulus value for Non-Aged was observed in VarseoSmile
Crown Plus (8.24±1.37), followed by Ceramic Crown (7.57±1.08), and lastly Lava Ultimate
(6.04±0.96). (VS>CC>LU)
Aged: The maximum Weibull Modulus value for Aged was seen in VarseoSmile Crown Plus
(7.59±1.18), followed by Ceramic Crown (7.45±1.20), and lastly Lava Ultimate (3.42±0.56).
(VS>CC>LU)
Probability of Failure
Weibull plot:
The Weibull plot for the tested materials in both Aging at Airborne Particle Abrasion +
Adhesive surface treatment with the Weibull characteristic strength at the failure probability of
63.2% is shown in Figure 87.
Figure 87: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Airborne Particle Abrasion + Adhesive
In the plot, the Non-Aged at (PA) displayed the highest characteristic strength values with Lava
Ultimate, followed by Ceramic Crown, and lastly VarseoSmile Crown Plus. highest Weibull
Modulus value for Non-Aged was observed in VarseoSmile Crown Plus.
173
Whereas the Aged at (PA) was lower with VarseoSmile Crown Plus followed by Lava Ultimate,
and lastly Ceramic Crown. The highest Weibull Modulus value for Aged was seen in
VarseoSmile Crown Plus. The higher standard deviation of the µTBS values impacted the shape
of the slope (Weibull modulus) leading to scattered data causing a shallow slope.
Contour plot:
The likelihood contour plot for the tested materials in different aging at (PA) surface treatment is
shown in Figure 88.
On the plot, the Lava Ultimate doesn’t intersect, indicating a statistically significant difference
before and after aging. On the plot, VarseoSmile Crown Plus, Ceramic Crown intersects
which indicates no statistically significant difference before and after aging. The highest overlap
was observed beween (VS.NA) and (CC.A).
Figure 88: Likelihood Contour Plot (Airborne Particles Abrasion +Adhesive)
174
5.2.8. Airborne Particle Abrasion + Silane + Adhesive (PSA):
The Two-parameters, Characteristic Strength (σ�) and Weibull Modulus (�) at the Airborne
Particle Abrasion+ silane + Adhesive surface treatment of the tested materials in Non-Aged
and Aged are presented in Table 111.
Table 111: Weibull Distribution (Two Parameters) Characteristic Strength (�o) and Weibull Modulus (m) of Airborne Particle
Abrasion+ Silane+ Adhesive treatment
Overall, the highest Characteristic Strength in the (PSA) was found in the Non-Aged Lava
Ultimate (87.26±1.98MPa). Moreover, the highest Weibull Modulus was also found in Aged
Ceramic Crown (11.94±1.86MPa).
Weibull Characteristic Strength (σ�)
Non-Aged: The Characteristic Strength value was highest in Lava Ultimate (87.26±1.98MPa),
followed by Ceramic Crown (57.17± 2.52MPa), and lastly VarseoSmile Crown Plus (44.42±
1.26MPa). (LU>CC>VS)
Aged: The highest Characteristic Strength value was seen in Ceramic Crown (57.17± 2.52MPa),
followed by Lava Ultimate (52.61±2.58MPa), and lastly VarseoSmile Crown Plus
(45.24±1.51MPa). (CC>LU>VS)
Weibull Modulus (�)
Material Aging
��
Mean
�� SD
�
Mean
�SD
Lava Ultimate
Non -Aged 87.26 ± 1.98 9.30 ± 1.48
Aged 52.61 ± 2.58 4.32 ± 0.65
VarseoSmile Crown Plus Non -Aged 44.42 ± 1.26 7.48 ± 1.05
Aged 45.24 ± 1.51 6.32 ± 0.96
Ceramic Crown Non -Aged 57.17 ± 2.52 4.82 ± 0.67
Aged 49.08 ± 0.87 11.94 ± 1.86
175
Non-Aged: The highest Weibull Modulus value for Non-Aged was observed in Lava Ultimate
(9.30±1.48), followed by VarseoSmile Crown Plus (7.48±1.05), and lastly Ceramic Crown
(4.82±0.67). (LU>VS>CC)
Aged: The maximum Weibull Modulus value for Aged was seen in Ceramic Crown
(11.94±1.86), followed by VarseoSmile Crown Plus (6.32±0.96), and lastly Lava Ultimate
(4.32±0.65). (CC>VS>LU)
Probability of Failure
Weibull plot:
The Weibull plot for the tested materials in both Aging at Airborne Particle Abrasion + Silane
+Adhesive surface treatment with the Weibull characteristic strength at the failure probability of
63.2% is shown in Figure 89.
Figure 89: Weibull Plot (Plots of Failure Probabilities Against µTBS Strengths) at Airborne Particle Abrasion +Silane + Adhesive
In the plot, the Non-Aged at (PSA) displayed the highest characteristic strength values with Lava
Ultimate, followed by Ceramic Crown, and lastly VarseoSmile Crown Plus. The Characteristic
Strength value was highest in Lava Ultimate. Whereas the Aged at (PSA) was lower with
176
VarseoSmile Crown Plus followed by Lava Ultimate, and lastly Ceramic Crown. The maximum
Weibull Modulus value for Aged was seen in Ceramic Crown. The higher standard deviation of
the µTBS values impacted the shape of the slope (Weibull modulus) leading to scattered data
causing a shallow slope.
Contour plot:
The likelihood contour plot for the tested materials in different aging at (PSA) surface treatment
is shown in Figure 90. Figure 90: Likelihood Contour Plot (Airborne Particles Abrasion + Silane+ Adhesive)
On the plot, the Lava Ultimate, Cerammic Crown doesn’t intersect, indicating a statistically
significant difference before and after aging. On the plot, VarseoSmile Crown Plus intersects
which indicates no statistically significant difference before and after aging.
5.3. Artificial Aging:
5.3.1. Overall:
The two parameters, characteristic strength (σ�) and Weibull modulus (�), presented higher
values in non-aged groups compared to aged groups (Table 100). The likelihood contour plots
that were used to determine the statistically significant differences between the two parameters it
177
depend into the materials and surface treatment but the Lava Ultimate doesn’t in all the surface
treatment (Figure 76, Figure 78, Figure 80, Figure 82, Figure 84, Figure 86, Figure 88, Figure
90). This indicates that before and after aging are statistically significantly different for Lava
Ultimate. But for the VarseoSmile Crown Plus was intersect in all surface treatment indicate no
statistically significant difference Before and After aging. While, the Ceramic Crown it depend
on the surface treatments its intersect in (PA, SA, A, S)which indicate no statistically
significantly different Before and After aging. And doesn’t intersect in (C,P,PS,PSA) which
indicate Before and After aging are statistically significantly different.
6. Results Summary:
A summary of the results is presented in
Table 112 showing the statistically significant differences seen based on the material in the
group-wise comparisons of the µTBS data as well as the statistically significant difference seen
in the likelihood contour plot of the Two-parameter Weibull distribution (Weibull modulus and
Characteristic strength). Similarly, a summary of the results showing the Statistically significant
differences based on the Surface Treatments is shown in Table 113.
Table 112: Result Summary of the Group-wise Comparison (µTBS) and the Weibull Distribution (Two-Parameters) Based on the
Materials.
Materials Aging Surface Treatment Micro Tensile
bond strength
Weibull
distribution
Lava Ultimate
Non Aged -
Control
P Significant Significant
S Significant Significant
A Not Significant Significant
PS Significant Significant
SA Not Significant Significant
PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion
S Significant Significant
A Significant Significant
PS Significant Not Significant
SA Not Significant Significant
PA Significant Not Significant
PSA Not Significant Not Significant
Silane
A Significant Significant
PS Significant Significant
SA Significant Significant
PA Significant Significant
PSA Significant Significant
Adhesive
PS Significant Significant
SA Not Significant Not Significant
PA Significant Significant
178
PSA Significant Significant
Airborne Particle Abrasion + Silane
SA Significant Significant
PA Not Significant Not Significant
PSA Not Significant Not Significant
Silane + Adhesive PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion + Adhesive PSA Not Significant Significant
Aged
Control
P Significant Significant S Significant Significant A Not Significant Not Significant
PS Significant Significant
SA Not Significant Significant
PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion
S Significant Significant A Significant Significant
PS Not Significant Not Significant
SA Significant Significant
PA Not Significant Not Significant
PSA Not Significant Not Significant
Silane
A Significant Significant
PS Significant Significant
SA Not Significant Significant
PA Significant Significant
PSA Significant Significant
Adhesive
PS Significant Significant
SA Not Significant Significant
PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion + Silane
SA Significant Significant
PA Significant Significant
PSA Not Significant Not Significant
Silane + Adhesive PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion + Adhesive PSA Not Significant Not Significant
VarseoSmile Crown Plus
Non -Aged
Control
P Significant Significant S Not Significant Not Significant A Significant Significant
PS Significant Significant
SA Not Significant Significant
PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion
S Significant Significant A Significant Significant
PS Not Significant Not Significant
SA Significant Significant
PA Not Significant Not Significant
PSA Not Significant Not Significant
Silane
A Significant Significant
PS Significant Significant
SA Not Significant Significant
PA Significant Significant
PSA Significant Significant
Adhesive
PS Significant Significant
SA Not Significant Not Significant
PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion + Silane
SA Significant Significant
PA Not Significant Not Significant
PSA Not Significant Not Significant
Silane + Adhesive PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion + Adhesive PSA Not Significant Not Significant
A
g
e
d
Control
P Significant Significant S Not Significant Not Significant
179
A Not Significant Significant
PS Significant Significant
SA Not Significant Significant
PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion
S Significant Significant A Significant Significant
PS Not Significant Significant
SA Significant Significant
PA Not Significant Significant
PSA Not Significant Not Significant
Silane
A Not Significant Not Significant
PS Significant Significant
SA Not Significant Not Significant
PA Significant Significant
PSA Significant Significant
Adhesive
PS Significant Significant
SA Not Significant Not Significant
PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion + Silane
SA Significant Significant
PA Not Significant Not Significant
PSA Not Significant Not Significant
Silane + Adhesive PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion + Adhesive PSA Not Significant Not Significant
Ceramic Crown
Non -Aged
Control
P Significant Significant S Significant Significant A Significant Significant
PS Significant Significant
SA Significant Significant
PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion
S Not Significant Not Significant A Not Significant Not Significant
PS Not Significant Not Significant
SA Not Significant Not Significant
PA Significant Not Significant
PSA Not Significant Not Significant
Silane
A Not Significant Not Significant
PS Not Significant Not Significant
SA Not Significant Not Significant
PA Significant Significant
PSA Significant Significant
Adhesive
PS Not Significant Not Significant
SA Not Significant Not Significant
PA Significant Significant
PSA Significant Not Significant
Airborne Particle Abrasion + Silane
SA Not Significant Not Significant
PA Significant Significant
PSA Not Significant Not Significant
Silane + Adhesive PA Not Significant Significant
PSA Not Significant Not Significant
Airborne Particle Abrasion + Adhesive PSA Not Significant Not Significant
Aged
Control
P Significant Significant S Significant Significant A Significant Significant
PS Significant Significant
SA Significant Significant
PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion
S Not Significant Not Significant A Not Significant Not Significant
PS Significant Significant
SA Not Significant Not Significant
180
PA Significant Significant
PSA Not Significant Significant
Silane
A Not Significant Not Significant
PS Significant Significant
SA Not Significant Not Significant
PA Significant Significant
PSA Significant Significant
Adhesive
PS Significant Significant
SA Not Significant Not Significant
PA Significant Significant
PSA Significant Significant
Airborne Particle Abrasion + Silane
SA Significant Significant
PA Not Significant Not Significant
PSA Significant Significant
Silane + Adhesive PA Significant Significant
PSA Not Significant Significant
Airborne Particle Abrasion + Adhesive PSA Significant Significant
181
Table 113:Results Summary of the Group-wise Comparisons (µTBS) and Weibull Distribu0on (Two-parameters) Based on Surface Treatments.
Surface Treatment Aging Materials Micro Tensile
bond strength
Weibull
distribution
Control
Non- Aged
Lava Ultimate VarseoSmile Crown Plus Not Significant Significant
Ceramic Crown Significant Significant
VarseoSmile Crown Plus Ceramic Crown Significant Significant
Aged
Lava Ultimate VarseoSmile Crown Plus Significant Significant
Ceramic Crown Significant Significant
VarseoSmile Crown Plus Ceramic Crown Significant Significant
Airborne Particle Abrasion
Non- Aged
Lava Ultimate VarseoSmile Crown Plus Significant Significant
Ceramic Crown Significant Significant
VarseoSmile Crown Plus Ceramic Crown Not Significant Significant
Aged
Lava Ultimate VarseoSmile Crown Plus Significant Not Significant
Ceramic Crown Significant Not Significant
VarseoSmile Crown Plus Ceramic Crown Not Significant Not Significant
Silane
Non- Aged
Lava Ultimate VarseoSmile Crown Plus Significant Significant
Ceramic Crown Not Significant Significant
VarseoSmile Crown Plus Ceramic Crown Significant Significant
Aged
Lava Ultimate VarseoSmile Crown Plus Significant Not Significant
Ceramic Crown Significant Significant
VarseoSmile Crown Plus Ceramic Crown Significant Significant
Adhesive
Non- Aged
Lava Ultimate VarseoSmile Crown Plus Not Significant Significant
Ceramic Crown Significant Significant
VarseoSmile Crown Plus Ceramic Crown Significant Significant
Aged
Lava Ultimate VarseoSmile Crown Plus Significant Significant
Ceramic Crown Significant Significant
VarseoSmile Crown Plus Ceramic Crown Significant Significant
Airborne Particle Abrasion
+ Silane
Non- Aged
Lava Ultimate VarseoSmile Crown Plus Significant Significant
Ceramic Crown Significant Significant
VarseoSmile Crown Plus Ceramic Crown Significant Significant
Aged
Lava Ultimate VarseoSmile Crown Plus Significant Significant
Ceramic Crown Not Significant Not Significant
VarseoSmile Crown Plus Ceramic Crown Significant Significant
Silane + Adhesive
Non- Aged
Lava Ultimate VarseoSmile Crown Plus Not Significant Not Significant
Ceramic Crown Significant Significant
VarseoSmile Crown Plus Ceramic Crown Significant Significant
Aged
Lava Ultimate VarseoSmile Crown Plus Significant Significant
Ceramic Crown Significant Significant
VarseoSmile Crown Plus Ceramic Crown Significant Significant
Airborne Particle Abrasion
+ Adhesive
Non- Aged Lava Ultimate VarseoSmile Crown Plus Significant Significant
Ceramic Crown Significant Significant
VarseoSmile Crown Plus Ceramic Crown Significant Significant
Aged Lava Ultimate VarseoSmile Crown Plus Not Significant Significant
Ceramic Crown Significant Significant
VarseoSmile Crown Plus Ceramic Crown Significant Significant
Airborne Particle Abrasion
+ Silane +Adhesive
Non- Aged Lava Ultimate VarseoSmile Crown Plus Significant Significant
Ceramic Crown Significant Significant
VarseoSmile Crown Plus Ceramic Crown Significant Significant
Aged Lava Ultimate VarseoSmile Crown Plus Not Significant Significant
Ceramic Crown Not Significant Significant
VarseoSmile Crown Plus Ceramic Crown Not Significant Significant
182
Chapter Four: Discussion
The objective of this study was to observe the effect of different surface treatments on the micro
tensile bond strength with and without artificial aging of three CAD/CAM materials. One was a
subtractively manufactured material, and two were additively manufactured materials for
permanent indirect restorations. The data indicate that the µTBS values vary among different
materials, among different surface treatments, and among different stages of artificial aging, thus
rejecting all null hypotheses.
1. Materials:
In the current study, the additive material Ceramic Crown shows higher µTBS compared to other
tested materials. The bond strength of indirect restorations to resin cement is affected by several
factors, such as the microstructure of the restorative material, the type of cement material, the
chemical composition of silane, the surface treatment procedure, and the cementation procedure.
(157, 164) Research has shown that indirect resin restorations can be durably bonded by micromechanical interlocking and chemical bond.(165) The difference in µTBS of our tested materials
could be due to different composition and filler content. Lava Ultimate consists of fillers of about
80 wt% with silica particles of 20 nm and zirconia particle of 4 to 11 nm size.(20) For
VarseoSmile Crown Plus, filler content is around 30 – 50 % by mass with a particle size 0.7 μm
which is considered bigger than the Lava Ultimate. Ceramic Crown contains around 20-60%
fillers, but the manufacturer does not disclose the filler size and type.
The polymer-infiltrated ceramic Vita Enamic (EN), produced through subtractive manufacturing,
includes porous pre-sintered feldspar ceramic 86 wt% and traditional polymers 14 wt%, UDMA
and TEGMA. It exhibited significantly higher bonding to both dentin and titanium compared to
the two composite resins manufactured additively, regardless of the type of resin cement
used.
(166) The better bond strength to dentin of EN over that of more composite resin-like
materials was also reported by Cekic-Nagas et al. (167) The differences between the tested
materials can be adributed to microstructural differences. It reported significantly higher pulloff bond strengths of EN crowns bonded to a glass fiber-reinforced high-performance polymer
with den=n-like proper=es than VS crowns, (168) which was consistent with other studies.
(166)
183
One possible explanation for the better bonding performance of EN over CrownTec (CT) and VS
in the present study would be a higher degree of conversion from the controlled and optimized
polymerization of the blocks from which the specimens were manufactured. (169) Statistically
similar bond strength results of CT and VS support this hypothesis and might indicate a potential
bond-deteriorating effect of residual monomer at the restorative material-resin cement interface
as there is a positive correlation between the filler content of resin-based materials and bond
strength. (170) An additional explanation may be the surface treatments. Under the manufacturers’
instructions, CT and VS were airborne particle abraded. At the same time, EN, having the highest
ceramic content of the tested materials, was etched with hydrofluoric acid, and subsequently
treated with a ceramic primer that comprised of phosphate monomers. A previous study on the
SBS of different CAD-CAM ceramic-glass polymers also reported higher bond strengths for EN
compared with materials with lower ceramic content, even though they were also acidetched.
(170)
1.1.Factors Affecting the mechanical Properties of 3D Printed Materials:
1.1.1. Degree of Conversion and Post-Curing Procedures:
The liquid resin used in the printing machine contains monomers, filler particles, and
photoinitiators. When the UV light activates the photoinitiators in the resin, the monomer
polymerizes with each other, forming polymers consisting of a bonded chain at the
macromolecular level; this happens by rapid creation of the layer-by-layer, which may lead to
insufficient cure density throughout each layer added. Consequently, long-chain crosslinking is
less effective, and lower double-bond formation affects its mechanical properties.(171) In contrast,
a CAD/CAM milling block produced under high temperatures and pressure is characterized by
longer double bonds, reduced distances between molecules, and a denser structure.(172) Thus,
high monomer conversion results in less residual monomer.(173) Based on one study comparing
the mechanical properties of milled versus printed resin, residual monomers may explain why 3D
printed resins exhibit relatively lower mechanical properties than milling resins.(174) Their
investigation revealed that the subtractive material, Lava Ultimate, boasts higher physical
properties. Specifically, Lava Ultimate demonstrates high flexural strength (203.61± 37.41 MPa),
a modulus of elasticity of (17.25 ± 3.61 GPa), and microhardness (121.70 ± 16.30 VHN). In
184
contrast, the VarseoSmile Crown Plus exhibits noticeably lower physical properties, with a lower
flexural strength (87.89 ± 23.10 MPa), a reduced modulus of elasticity (6.79 ± 6.17 GPa), and
significantly lower microhardness (45.78 ± 14.45 VHN) compared to Lava Ultimate.Moreover,
they found that the difference in post-processing gives Saremco Print Crowntec(CT) relatively
better mechanical properties than other 3D printing resins (Varseo Smile Crown Plus(VS) and
Formlab Permanent Crown (FLP)). The post-processing, they used for SCT was curing with
4000 lighting exposures while in the nitrogen oxide gas atmosphere, while VS was also placed in
nitrogen oxide gas with a pressure of 1.0–1.2 bar and cured in 1500 flashes with ten light
frequencies per second. In comparison, FLP was not placed in a nitrogen oxide gas atmosphere,
only cured in UV light 390–405 nm at 60°C for 20 min.(174) In our investigation, there was a
variation in post-processing procedures among the materials according to manufacturer's
instructions. Specifically, VarseoSmile Crown Plus underwent a double curing process in
ProCure for 20 minutes at 20ºC, while Ceramic Crown was post-cured in ProCure 2, following
the manufacturer's instructions. These discrepancies in equipment and post-curing times and
temperatures could potentially impact the bond strength if any residual unpolymerized resin
remains on the material's surface, ultimately leading to increased adhesion with the resin cement.
This scenario may explain why Ceramic Crown, particularly in the control treatment, exhibited
the highest µTBS. This circumstance could also clarify why Ceramic Crown demonstrated both
the highest µTBS and a higher occurrence of cohesive failures. There is a need for further
investigation to determine whether the different machines and curing times will affect the
bonding strength of tested materials.
1.1.2. Layer Thickness:
To create the specimens in the 3D printer, thin layers of composite resin were cured to reach the
desired thickness of the specimens. The thickness and orientation of layers can significantly
impact the surface and mechanical quality of the final product.(172) The thickness of the layers
affected 3D-printed temporary crowns. Printing temporary crowns with a layer thickness of 20 or
50 µm rather than 100 µm is preferable for better trueness and margin quality.(175) Depending on
the layer thickness, three-dimensional printed restorations can have different physical and
mechanical properties. A 50 mm layer thickness significantly increased the flexural strength of
185
the 3D-printed permeant crown. (176) As well as in other studies, specimens were printed at 90°
and the force for the flexural strength was applied parallel to test layers. To reduce the
polymerization shrinkage by decreasing the layer thickness, 50 μm was chosen. (174) It is possible
that the voids formed between successive layers of specimens during this additive manufacturing
process. As a result, the mechanical structure becomes weaker due to weaker bonds between the
layers, which easily delaminated.(177) In this study, the failure mode of the printed materials was
mostly cohesive in resin, which could be due to the weaker bonds between the printed layers.
1.1.3. Printing Angulation:
Printing angulation influences the mechanical properties of the 3D printing material. Vertically
printed specimens with the layers oriented perpendicular to the load direction have improved
mechanical properties more than horizontally printed specimens with the layers oriented parallel
to the load direction. (178) The 45º printing direction was more accurate than the 0º and 90º
printing directions in the removable appliance.(179) Another study printed full coverage with
different printing angulations (90º ,120º ,135º ,150º ,180º ,210º, 225º, 240º, and 270º), and they
concluded that a 120 º build angle showed a minimal deviation of 0.029 mm for thin support and
0.031 mm for thick support.(180) In our study, a 45 º angulation with standard support size was to
get the maximum accuracy even though the spacemen were cuboid-shaped.
1.1.4. Printers:
SLA printers cure the liquid resin layer-by-layer using a microlaser point. Digital mirror devices
that control lasers are used in DLP printers for liquid polymerization.(181) An investigation was
conducted on the flexural strengths of temporary fixed restorations produced by the SLA and
DLP techniques. There was no significant difference between these two groups. For flexural
strength (DLP technique), the Saremco Print Crowntec group showed the highest value,
Following Formlabs 3B Permanent Crown- (SLA technique) and Varseo Smile Crown plus
(DLP technique).(182) Research was conducted on the mechanical properties of denture base
materials produced by 3D printing and CAD/CAM milling. According to their results, the test
specimens made using DLP (ASIGA DentaBase) had the highest value, followed by FormLabs
Prosthetic Base LP and DLP (Prosthetic 3D+). According to them, DLP and SLA techniques
186
were similar. (172) In the current study, two different printers were used, SprintRay Pro 55S and
SprintRay Pro95, both used (DLP technique). It would be helpful to conduct more studies about
permanent composite 3D printed materials, such as printing techniques, layer thickness, and
printing directions.
2. Surface Treatment:
2.1.Control
In the control group, where two polished and clean surfaces of the same material were bonded
using a dual-cure resin cement (RelyX Ultimate), the µTBS was generally lower for all tested
materials. The highest µTBS of the control group was observed in Ceramic Crown followed by
VarseoSmile Crown Plus. This variance can likely be attributed to residual unpolymerized resin
on the surface or the filler size of different materials. It's important to note that the size and shape
of filler particles have a considerable impact on the surface roughness of composite materials,
(183)
As higher surface roughness is typically associated with larger filler particles. (184-186) In the case
of VarseoSmile Crown Plus, the presence of larger filler particles contributes to stronger µTBS
when compared to Lava Ultimate. We can infer that the Ceramic Crown likely has larger filler
particles, which would lead to an increase in surface roughness and, consequently, an increase in
µTBS. Adhesive failure was the predominant mode of debonding in the control group of all for
all materials, occurring in approximately 84.67% of cases. The exception was Lava Ultimate in
the control group after aging, which experienced a pretesting failure rate of 84%. This deviation
might be due to the smaller filler size or the complete polymerization of the bonded surface due
to its industrial fabrication process.
2.2.Airborne Particle Abrasion
Airborne particle abrasion is suggested as an alternative to acid etching.(35) Airborne particle
abrasion can roughen the surface of resin composites, increase surface energy, and enable cement
to penetrate the material, thereby promoting a strong bond between the cement and restorative
material and improving micromechanical interlocking.(187)
For Lava Ultimate, the manufacturer
has not recommended acid etching, presumably because of the zirconia nanoparticles in the
material. Another article stated that sandblasting had a positive effect on bond strength for Lava
187
Ultimate. On the contrary, another study said sandblasting for Lava Ultimate did not show a
significant difference compared to the acid etching and acid etching + universal adhesive
groups.(188) According to our current study, applying airborne particle abrasion significantly
increases the tested materials' bonding strength. However, with airborne particle abrasion, the
failure mode is mostly cohesive in resin material, especially for printed materials Cohesive
failures predominantly take place in the materials subjected to airborne particle abrasion,
typically occurring at a significant distance from the bonding region. This phenomenon can be
attributed to imperfections arising during the printing process or the presence of weak,
unpolymerized resin between the printed layers.
2.3.Coupling Agents:
HF acid etching or sandblasting in combination with a silane pre-treatment was more effective
than mechanical surface treatment alone for Enamic; there were no significant differences among
various surface treatments for Lava Ultimate,
(189) which was confirmed by one of the studies that
pre-treatments with silane increased bond strength values significantly for both Lava Ultimate
and Enamic.(190) Another study found no significant differences among the pre-treated groups
with and without silane. (191) Our data confirm that the use of silane after the airborne particle
abrasion increases the µTBS of the Lava Ultimate, but the different was not significant. Using
the silane alone gives a significantly lower bonding strength compared to airborne particle
abrasion. This discrepancy may be caused by the different types of chemical agents; some
research used 10-methacryloyloxydecyl dihydrogen phosphate (MDP). (190) Further, stated that
resin cements containing MDP monomers have higher bond strengths than other adhesive
cements.(192, 193) The use of silane in VarseoSmile Crown Plus does not result in a significant
increase in the µTBS compared to control. When silane is combined with airborne particle
abrasion, the µTBS of VarseoSmile Crown Plus does increase, but this increase is not statistically
significant when compared to airborne particle abrasion alone. In the case of Ceramic Crown, the
use of silane leads to statistically significant increase in microtensile bond strength (µTBS).
However, this increase is still significantly lower than when airborne particle abrasion is
followed by silane. On the other hand, treatment with airborne particle abrasion alone does not
show a significant difference compared to the use of silane alone.
188
Chemical surface treatment can improve the bonding strength between 3D printing materials and
resin cement. One of the main components of the adhesives used for bonding resins is a
functional monomer, mainly 10-MDP. The MDP monomer presents better adhesion results when
combined with Airborne particle abrasion. (194, 195) Single Bond Universal is a universal adhesive
containing silane introduced for use in surface treatments before adhesive cementation of indirect
composite or ceramic restorations. The application of silane increases wettability and, therefore,
enables the formation of covalent bonds between the restorative material and resin cement. (164)
Another article reported that adding a silane-monomer mixture to various dental materials,
including ceramic, resulted in high bond strength values. (196) Other studies, showed that the
application of silane had a positive effect on the bond strength to direct composite
restorations.(197-199)
In contrast, some studies could not find a beneficial effect.(200, 201) However,
the groups that applied Single Bond Universal after sandblasting showed the highest µTBS
statistically among the surface treatment groups for Lava Ultimate and Estenia C&E materials.
(188) They suggested that application of a universal adhesive following sandblasting can be
recommended as an ideal surface treatment method for both materials. (188)
2.4.Adhesive:
A primary component found in universal adhesives is a functional monomer, typically 10-
methacryloyloxydecyl dihydrogen phosphate (10-MDP).(202, 203) Adhesives also contain the BisGMA monomer, which has the ability to impede the reaction between silane and the hydroxyl
groups present in silica-based restorative materials.(45) Past research has pointed out that the
compatibility between the hydroxyl groups of inorganic filler particles in the substrate and the
hydrolysable functional groups of silane plays a pivotal role in determining bond strength. (204)
Another study discovered that achieving higher bond strength values necessitated the additional
application of silane, suggesting that the quantity of silane within universal adhesives may not
offer sufficient compatibility. (205) Similar results were reported, in which the highest bond
strength values were obtained with additional silane application compared to the silanecontaining universal adhesive alone.(206) Both studies and the literature,
(205-207)suggest that silane
in universal adhesives is not an alternative to additional silane application. In our study, it was
observed that the application of the adhesive alone or in conjunction with silane did not result in
189
a significant distinction across all tested materials. This lack of difference may be attributed to
the fact that the silane used in our study was a mixture of 10-MDP and disulfide methacrylate.
3. Failure Mode:
In our study, we observed four failure modes: adhesive, cohesive in cement, cohesive in material,
and mixed. Previous research reported that reduced bond strength values were mostly related to
adhesive failure rates. (157, 208) In another study testing Lava Ultimate and Estenia C&E, the
control group resulted in the lowest µTBS values with the highest numbers of adhesive
failures.
(188) The results of our study confirmed these findings. As for the control group, we
observed pretesting failures and low µTBS for Lava Ultimate, while for other tested materials,
low µTBS with out any pre testing failure. Also, it has been reported that mixed and cohesive
failures were clinically more acceptable than adhesive failures. Cohesive failures in cement point
to favorable bonding conditions.(208) They also reported that among the tested surface treatment
groups, the sandblasting + universal adhesive groups had the highest µTBS values, and these
groups also had the highest rates of cohesive failures in materials. For both materials, using a
universal adhesive following sandblasting significantly increased bond strength values and
materials cohesive failure rates.(188)
The failure mode in the printed materials was mostly cohesive in material with 61.25% for
Ceramic Crown and 43.25% for VarseoSmile Crown Plus. Lava Ultimate demonstrated mostly
adhesive failures with 61.75% and only 11.75% cohesive failure in the material. The amount of
cohesive failures in material increased with the surface treatments performed airborne particle
abrasion. This may be due to the defects created by AlO3 particles 50 µm with 2 bar pressure,
resulting in increased micromechanical interlocking. The fast process of printing could result in
uncured resin between the printed layers which will reduce the DG of convergence. (171) This
may lead to a reduction in the strength of the material and increase the chance of cohesive failure
in the material. Lastly, the imperfections introduced during the printing process can lead to a
reduction in the strength of the printed material, resulting in its cohesive failure.
4. Aging:
190
The ISO/TS 11405:2003 suggested three conditions for the durability test: I. short-term storage
for 24h in water 37ºC; II. Thermocycling after 24h of water storage for 500 cycles in water
between 5 ºC and 55 ºC exposure in each bath 20s and transfer time 5 to 10 s; III. Also,
extended storage time for six months in water at 37ºC, changing the water every seven days to
avoid contamination, has been used. (209) In most studies, thermocycling artificial aging was used
because thermocycling has established itself as suitable for simulating temperature changes in
the oral cavity.
(210, 211) In our study, half of the bond strength measurements were performed after
thermal aging of 10,000 cycles between 5 and 55 °C. Ten thousand cycles are equivalent to about
one year of use, but thermocycling is only an approximation for certain intraoral situations to
simulate, e.g., hot food or ice cream. (210) Our study used the thermocycling artificial aging for
20,000 cycles in distilled water at temperatures of 5 ºC and 55 ºC with 30 s dwell time and 15 s
transfer time, equivalent to 2 years. The study found different results on the shear bond strength
and tensile bond strength values after aging, they reported increasing shear bond strength values
after thermal aging. (212) Lower values after artificial aging may be caused by mechanical stress
in the bonding interface caused by volumetric changes due to thermal expansion and contraction.
Some studies reported an increase in bond strength after thermocycling. This could be explained
by promotion of post-polymerization of the luting agent under the high temperature during
thermocycling. In addition, water absorption during thermal cycling causes 3D resin material to
expand, which may affect the anchorage of the luting composite resin.(213) 3D printed material
(D20II, Rapid Shape) thermocycled for 10,000 cycles between 5° and 55 °C remaining for 20 s
in each bath, were positively affected in terms of bond strength.
(213) Another study stated that
thermocycling increased the degree of convergence of micro-hybrid resin composite and reduced
surface microhardness and flexural strength.(214) Thermocycling positively affects interim
CAD/CAM material milled or printed. The milled and printed materials have higher mechanical
proprieties toughness, resilience, and flexural strength compared to conventional polymethyl
methacrylate (PMMA) and bis-acryl resin (bis-acryl) after 10,000 cycles.(215) According to our
data, artificial aging for the milled material Lava Ultimate significantly reduced the µTBS. As
for the printed materials, µTBS to VarseoSmile Crown Plus did not change significantly after
aging, regardless of the surface treatment. However, Ceramic Crown increased significantly in
µTBS, especially with surface treatments airborne particle abrasion with silane and airborne
particle abrasion with adhesive. The failure patterns for the aged samples were predominantly
191
adhesive with 58%, while in non-aged were 46.5% cohesive in material, regardless of the surface
treatment.
5. Testing:
Several bond strength measurement methods can be considered when evaluating adhesive
properties. Among others, these can be macro-shear bond and macro-tensile bond strength tests
(216) and micro-shear and micro tensile tests. Micro-tests provide higher bond strength values than
their equivalent macro-tests.
(217, 218) However, the shear-bond strength test has been repeatedly
documented to result in inhomogeneous stress distribution along the interface, often leading to
‘cohesive’ failures in the substrate than to ‘adhesive’ failures at the actual interface.
(164, 216, 219) In
addition, the discriminative power of a shear-bond strength test is much lower than that of a
µTBS test,
(220) because of which the latter µTBS approach was employed in this study. A
limitation of the µTBS test is that the interfacial area of each specimen is very small.
Therefore, the test does not sample a wide variety of surface defects. Some specimens may
contain a severe defect, while others would be relatively high quality. Larger specimens would
probably have at least one severe defect in every specimen. Micro tensile specimens may have
resulted in artificially low values for Weibull modulus compared to the clinical case. They opted
to prepare a circular constriction at the interface, to remove the excess cement consistently and
controlled. In this method, however, the specimens were loaded at a constant displacement rate,
even though they did not all have the same cross-sectional diameter perfectly. This has probably
resulted in different stressing rates and typically in greater scatter of strength values.
Furthermore, zirconia ‘‘sandwich’’ micro-specimens were prepared instead of ‘‘zirconia-cementtooth’’ assemblies, by which only the bond to zirconia (and not that to dentine) was measured;
hence, any biologic tooth-variance effects were excluded.
(158, 221) As in our study, we adopted the
sandwich to eliminate the biological factors. And focus on the bonding strength between the
tested resin cement in different surface treatments.
192
6. Violation of ANOVA prerequisites:
Normality:
Only 12 variables out of 48 deviated from normality (25%). The histograms of these variables
reveal that the deviation is relatively slight for most of them. Also, no exaggerated or extreme
data was evident in any of them. An ANOVA is relatively robust against violations of the
normality assumption, which means the Type 1 error rate remains close to the alpha level
specified in the test.(222) When data are not normally distributed (e.g., skewed, zero-inflated,
binomial, or count data), researchers are often uncertain whether it may be legitimate to use tests
that assume Gaussian errors (e.g., regression,t-test, ANOVA, Gaussian mixed models), or
whether one has to either model a more specific error structure or use randomization techniques.
Monte Carlo simulations were used to explore the pros and cons of fitting Gaussian models to
non-normal data regarding risk of type I error, power, and utility for parameter estimation. They
showed that Gaussian models are remarkably robust to non-normality over a wide range of
conditions. P-values remain pretty reliable except for data with influential outliers judged at strict
alpha levels. Gaussian models also perform well in terms of power, and they can be useful for
parameter estimation but usually not for extrapolation. Data transformation before analysis is
often advisable, and visual inspection for outliers and heteroscedasticity is important for
assessment.(161)
In contrast, some non-Gaussian models and randomization techniques bear a range of risks that
are often insufficiently known. High rates of false-positive conclusions can arise, for instance
when overdispersion in count data is not controlled appropriately or when randomization
procedures ignore existing non-independencies in the data.(161) Overall, we argue that violating
the normality assumption bears limited and manageable risks. At the same time, several more
sophisticated approaches are relatively error-prone and challenging to check during peer review.
Hence, as long as scientists and reviewers are not fully aware of the risks, science might benefit
from preferentially trusting Gaussian mixed models in which random effects account for nonindependencies in the data in a transparent way. Anti-conservative P-values usually do not arise
from violating normality in Gaussian models (except for the case of influential outliers) but
rather from various kinds of non-independencies in the data.(223)
193
Homogeneity:
Some statisticians suggest never using Bartlett's test.(224) It is too sensitive to minor differences
that would not affect the overall variance. Also, Levene’s Test is robust because the true
significance level is very close to the nominal significance level for a large variety of
distributions.(225) It is not sensitive to symmetric heavy-tailed distributions. So, if the difference
in conflicts is slight, especially if your sample sizes are equal (or nearly so), you might be safe
ignoring Barlett's test. Do not be too quick to use the nonparametric Kruskal-Wallis test (or the
Mann-Whitney test when comparing two groups). While nonparametric tests do not assume
Gaussian distributions, the Kruskal-Wallis and Mann-Whitney tests believe the data distribution's
shape is the same in each group. So, if your groups have very different standard deviations and
are not appropriate for one-way, they should not be analyzed by the Kruskal-Wallis or MannWhitney test.(223) The difference in our study standard deviation is not huge, and the sample sizes
are equal; we are safe just ignoring the homogeneity of the variance test. For further
confirmation that the non-Homogeneity in our data will not affect the result, the Kruskal-Wallis
test was utilized and we reached the same conclusion as in parametric ANOVA .
7. Weibull Statistics for Bond Strength Data:
µTBS values cannot accurately describe the strength of brittle materials such as ceramics, resin
composites, and tooth structures (e.g., enamel and dentin) because these structures have several
strength-controlling flaws. Instead of a fixed probability approach, a probabilistic approach
considers the variation in area, size, and stress throughout the object of relevance. Based on the
Weibull statistical approach, defects or flaws in a structure are more likely to be found as the size
increases. In most other statistical analysis treatments, strength does not depend on the size. A
resulting approach can be used to predict the useable design stresses for larger and more complex
bodies that can be tested in the lab safely.(163)
The adhesive bond of filled or unfilled resin to dentin lies in the same category of brittleness and,
thus, the presence of strength-controlling flaws. Using the Weibull distribution function
194
expressed by two parameters, the overall performance of these brittle materials and adhesives
bonded to dentin can be assessed better by predicting the likelihood of failure at specific stress
levels. The Weibull characteristic strength (σ�) and the Weibull modulus (m) reflect the flaw
distribution and, thus, the variability of the results.(226-228)
In the ISO/TS 11405:2003,
(209) the Weibull distribution is recommended for analyzing bond
strengths that do not follow a normal distribution. Many bond strength papers use means and
standard deviation rather than a probabilistic failure approach that provides insight into the
reliability of the Weibull modulus (�) parameter and failure probability. Shear, tensile, and
micro tensile coefficients of 20–50% variation indicate that the data do not fit a Gaussian
distribution. Critical flaws will result in high variability in the bond strength (i.e., high spread) of
an adhesive to dentin, resulting in a low Weibull modulus(�). Adhesives showing high Weibull
moduli are to be favored for achieving similar bond strength and are generally less technique
sensitive. In general, stainless steel has a Weibull m value of 100, engineering ceramics have a
value of 10, and chalk has a value of 5.(226) Other publications reported that Weibull modulus �
for porcelain and noble alloy ranges from 2.8 to 3.7,(229) and the resin composite ranges from 2.1
to 4.7.(163) According to our data its materials and surface treatment dependent for the Lava
Ultimate range from 1.17-9.30, VarseoSmile Crown Plus 1.66-8.24, and Ceramic Crown 2.64-
11.94. The highest Weibull modulus � was observed with surface treatment PSA.
195
Conclusions
Taking into account the limitations and conditions of this study, we can render the following
conclusions:
• Micro tensile bond strength values to milled and printed permanent CAD/CAM resin
materials are material dependent.
• The effect of artificial aging by thermocycling as well the effect of surface treatment is
material dependent.
• Bond strength increases upon application of airborne particle abrasion, resulting in more
cohesive failures in the material. Omission of airborne particle abrasion leads to more
adhesive failures.
• Higher Weibull modulus and Weibull characteristic strength values were observed in
milled material compared to printed materials, indicating a higher failure probability for
printed materials.
196
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Abstract (if available)
Abstract
Purpose: To evaluate influence of different surface treatments and artificial aging on the micro tensile bond strength (µTBS) of three milled and printed permanent CAD/CAM materials (Lava Ultimate [LU], VarseoSmile Crown Plus [VS], and Ceramic Crown [CC]).
Material and methods: Blocks of CAD/CAM materials (n=8/material; 14x14x6 mm; n=8/material; 14x14x5 mm) were fabricated by cutting from CAD/CAM blocks or by printing. After polishing of the bonding surface, specimens were divided into eight groups according to the surface treatment: control (C), Airborne Particle Abrasion (P), Silane (S), Adhesive (A), Airborne Particle Abrasion+ Silane (PS), Silane + Adhesive (SA), Airborne Particle Abrasion+ Adhesive (PA), and Airborne Particle Abrasion+ Silane +Adhesive (PSA). Blocks of 5- and 6-mm thickness with the same surface treatment were bonded together using a dual-cure resin cement (RelyX Ultimate). Every block was cut into 50 sticks with a dimension of 1.00 mm2 (±0.02). The sticks were subdivided into two subgroups: Non-Aged (.NA), and Aged (.A). µTBS test was performed using a universal testing machine. Data were analyzed using 3-way and 2-way ANOVA with Bonferroni post-hoc test (α=0.05). Weibull analysis was used to calculate the Weibull Modulus and Characteristic Strength to create Weibull plots and likelihood contour plots.
Results: The micro tensile bond strength of the materials differed significantly from each other (CC>LU>VS). A significant difference was found between the different surface treatments, regardless of the Artificial Aging (PA>PS>PSA>P>S>SA>A>C). Aging significantly reduces the µTBS of LU and CC but does not significantly affect the VS. The most frequent failure mode was cohesive in resin, while for the milled material it was predominantly adhesive. Higher Weibull modulus and characteristic strength values were observed with the milled material compared to the printed materials.
Conclusions: Surface treatment significantly affects µTBS to milled and printed direct CAD/CAM resin materials with increase of bond strength upon application of airborne particle. The adhesive interface of the milled material (LU) has a lower probability of failure than the interface of the printed materials (VS and CC).
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Mzain, Waad
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Micro tensile bonding strength to milled and printed permanent CAD/CAM materials
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School of Dentistry
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Master of Science
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Biomaterials and Digital Dentistry
Degree Conferral Date
2023-12
Publication Date
12/18/2023
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10/26/2023
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