University of Southern California Dissertations and Theses

A comparison of treatment time and number of appointments in active self-ligating brackets and conventionally ligated twin edgewise brackets

(USC Thesis Other)

A comparison of treatment time and number of appointments in active self-ligating brackets and conventionally ligated twin edgewise brackets

PDF

Download a page range

Download transcript

Copy asset link

Request this asset

Transcript (if available)

Content

A COMPARISON OF TREATMENT TIME AND NUMBER OF APPOINTMENTS IN
ACTIVE SELF-LIGATING BRACKETS AND CONVENTONALLY LIGATED TWIN
EDGEWISE BRACKETS
by
Lisa Miyuki Kai

A Thesis Presented to the
FACULTY OF THE USC GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
MASTER OF SCIENCE
(CRANIOFACIAL BIOLOGY)

May 2010

Copyright 2010 Lisa Miyuki Kai
ii

Dedication
This thesis is dedicated to my parents, Ken and Tae, and all my siblings, Marcus, Cheri,
Gina, Alan, and Kevin. Thank you for your love and support throughout all these years.
Without you I would not be where I am today.
iii

Acknowledgements
Dr. Glenn Sameshima: To my research advisor and chair of my thesis committee, thank
you for your time and guidance throughout the process.

Dr. Frank Yorita: Thank you for allowing me to access your records for data collection,
without which my research would not have been possible.
iv

Table of Contents

Dedication ii
Acknowledgements iii
List of Tables vi
List of Figures vii
Abstract ix
Chapter One: Introduction 1
Chapter Two: Literature Review 7
I. History and Development of the Edgewise System 7
A. The E-Arch 8
B. Pin and Tube 8
C. Ribbon Arch 9
D. Edgewise 10
II. The Modern Edgewise Appliance 13
III. History and Development of Self-Ligating Brackets 14
IV. Types of Orthodontic Ligation 21
V. Friction in Orthodontics 23
VI. Self-Ligating Systems 24
A. Ligation Time 24
B. Friction 26
C. Alignment Effectiveness 29
D. Treatment Time and Number of Appointments 30
E. Patient Comfort 33
F. Hygiene 33
Chapter Three: Hypothesis 35
Chapter Four: Materials and Methods 36
Chapter Five: Results 42
Chapter Six: Discussion 50
Chapter Seven: Conclusion 63
Bibliography 64
v

Appendices 71
I. Appendix A: Descriptive Statistics 71
II. Appendix B: Analyzed Data 72
III. Appendix C: Normality Distribution Graphs 79

vi

List of Tables

Table 1. Examples of self-ligating bracket designs 6
Table 2. Distribution of selected cases by bracket type 42
Table 3. Comparison of number of appointments in In-Ovation
®
R 42
and conventional groups

Table 4. Comparison of treatment time in In-Ovation
®
R and 43
conventional groups

Table 5. Comparison of age in In-Ovation
®
R and conventional groups 44
Table 6. Comparison of number of emergency appointments in 44
In-Ovation
®
R and conventional groups

Table 7. Comparison of number of broken brackets in In-Ovation
®
R 45
and conventional groups

Table 8. Comparison of number of missed appointments in 45
In-Ovation
®
R and conventional groups

Table 9. Descriptive statistics for In-Ovation
®
R and conventional groups 67

vii

List of Figures
Figure 1. Fauchard‘s bandeau 7
Figure 2. Angle‘s expansion E-arch 8
Figure 3. The pin and tube appliance 9
Figure 4. The ribbon arch. 10
Figure 5. The ribbon arch bracket 10
Figure 6. The basic elements of the ribbon arch appliance 10
Figure 7. The Edgewise arch 11
Figure 8. Edgewise paraphernalia 12
Figure 9. The edgewise arch bracket 12
Figure 10. The Russell attachment in open and closed positions 14
Figure 11. The Russell attachment components 15
Figure 12. The Edgelok bracket in open and closed positions 16
Figure 13. The SPEED™ bracket in open and closed positions 17
Figure 14. The Activa™ bracket in open and closed positions 17
Figure 15. The Time™ bracket in open and closed positions 18
Figure 16. The TwinLock™ bracket in open and closed positions 19
Figure 17. The Damon™ SL I bracket in open and closed positions and the 19
Damon™ SL II bracket

Figure 18. The In-Ovation
®
R bracket 20
Figure 19. The In-Ovation
®
R bracket in passive, expressive, and active 20
states

Figure 20. The Unitek SmartClip™ bracket 21
Figure 21. Mean number of total appointments for In-Ovation
®
R and 46
conventional groups
viii

Figure 22. Mean treatment time for In-Ovation
®
R and conventional groups 46
Figure 23. Mean age for In-Ovation
®
R and conventional groups 47
Figure 24. Mean number of emergency appointments for In-Ovation
®
R 47
and conventional groups

Figure 25. Mean number of broken brackets for In-Ovation
®
R 48
and conventional groups

Figure 26. Mean number of missed appointments for In-Ovation
®
R 48
and conventional groups

Figure 27. Normality distribution for number of appointments for 75
the conventional group

Figure 28. Normality distribution for treatment time for the conventional 75
group

Figure 29. Normality distribution for number of appointments for 76
In-Ovation
®
R group

Figure 30. Normality distribution for treatment time for In-Ovation
®
R 76
group

ix

Abstract

The use of self-ligating brackets has become widespread in orthodontics, and
manufacturers claim that they are more efficient. There are two main types of self-
ligating brackets—active and passive. Most of the previous studies on self-ligating
bracket efficiency have involved passive self-ligating brackets, and the few available
studies involving active self-ligating brackets include multiple confounding variables. In
the current retrospective study, treatment time and number of appointments were
compared between an active self-ligating appliance (In-Ovation® R ®; GAC
International, Bohemia, NY) and a conventionally ligated appliance (American
Orthodontics, Sheboygan, WI) in the non-extraction orthodontic treatment of Caucasian
females (ages 11-24 yr). Patients included were treated in a private orthodontic practice
with one provider. Treatment times were calculated using the patients‘ banding date and
debanding date, and the number of appointments (including emergency appointments)
was counted. As indicated by independent sample t-tests, there was no significant
difference (p=0.18) in treatment time between the In-Ovation® R (25.19 months) and
conventional (24.14) groups. However, In-Ovation® R cases required significantly
(p<0.001) fewer appointments compared to the conventionally ligated cases (17.52 and
26.48, respectively). In this study, it is concluded that In-Ovation® R active self-ligating
brackets require fewer appointments to complete orthodontic treatment, but do not
shorten overall treatment time.

1

Chapter One: Introduction

Orthodontics as a dental specialty is continually advancing and undergoing
changes. Along with the varying treatment philosophies and the demands of the patient,
orthodontic appliances have evolved over time. Around 3000 BC the ancient Egyptians
straightened teeth with crude metal bands wrapped around individual teeth with catgut to
close spaces (Wahl, 2004). In 1723 Pierre Fauchard, who is considered the ―Father of
Modern Dentistry‖ and ―Orthodontia‖ developed the bandeau or bandolet, which was the
first expansion appliance, made of a heavy maxillary labial arch to which teeth were
ligated. Fauchard‘s bandeau was the basis for Edward H. Angle‘s E (expansion) arch
(Wahl, 2004). It was soon realized that for effective tooth movement control of the
individual teeth was necessary. This notion led to the development of attachments that
were soldered on modified crowns or bands. Early appliances consisted of two molar
―anchor bands‘ or modified crowns with long tubes on the buccal surface, and a heavy
labial arch wire that followed the contour of the upper and lower arch. Movement was
accomplished by tipping the teeth out to ward he arch wire. Angle‘s philosophy was that
if teeth were placed in their proper occlusal relationship, normal function would develop
the supporting bone and hold the teeth in their position. Orthodontists learned that tipping
teeth did not provide the desired tooth movement, and they saw their cases collapse, and
realized that better control of individual teeth and movement of the root was necessary
(Graber, 1972). Angle created the E-arch in 1900, the pin-and-tube appliance in 1910,
the ribbon arch in 1916 and the edgewise appliance in 1925 (Wahl, 2002). The ribbon
2

arch wire was the first appliance with full three-axis control of tooth movement (Wahl,
2005). In the edgewise appliance Angle reoriented the slot from vertical to horizontal
and the arch wire was to be inserted on its ―edge.‖ This appliance was the first to
simultaneously move teeth in all three planes of space. Modern appliances are based on
this system (Wahl, 2005).
The most significant development of orthodontics in the second half of the 20
th

century was probably direct bonding. In the 1970s, instead of cementing bands to teeth,
orthodontist began directly bonding orthodontic brackets to teeth (Wahl 2002, Proffit,3
rd

ed.). Though the bracket was invented earlier, from the mid 1960s to the about 1970,
researcher worked on the development of a good adhesive for orthodontics. Directly
bonding brackets was not widely accepted until the late 1970s due to the reluctance to use
of acid etch on human teeth (Wahl, 2008). With the advent of directly bonding brackets
came the introduction of elastomeric ties in the 1970s to replace wire ligatures for their
ease and faster placement than steel ligatures. The elastomeric ties could also be used in
linked chains to close spaces and prevent spaces from opening.
The use of elastomeric ties has made the practice of orthodontics more efficient,
and thus has been adopted by the majority of practicing orthodontists. Although
elastomeric ties have been shown to reduce chairtime clinicians and manufacturers are
constantly searching for ways to improve bracket systems (Shivapuja et al., 1994, Maijer
et al., 1990). Elastomeric ties increase friction between the archwire and the bracket,
which makes closing spaces more difficult when using sliding mechanics. Clinically an
ideal ligation system would be secure and robust, ensure full bracket engagement of the
3

archwire, exhibit low friction between the bracket and archwire, but permit high friction
when desired, be quick and easy to use, permit easy attachment of an elastic chain, assist
in good oral hygiene, and be comfortable for the patient (Harradine, 2003). In addition to
the increase in friction between the archwire, another drawback to elastomeric ties is that
they result in diminished oral hygiene of the patient.
The drawback to using elastomeric ties is poorer oral hygiene of the patient and
also the addition of friction between the arch wire and the bracket. Especially in the
treatment of cases where permanent teeth are extracted, sliding mechanics is an important
part of orthodontic treatment. In an effort to reduce the amount of friction and improve
clinical efficiency, self-ligating brackets were developed. Hygiene in patient with treated
with self-ligating brackets may also be improved. Self-ligating brackets have been on the
market since the early 20
th
century, but have recently been resurging. In a 2002 Journal
of Clinical Orthodontics survey, it was found that only 8.7% of practitioners surveyed
reported using at least one self-ligating system (Keim et al., 2002). However, a 2008
Journal of Clinical Orthodontics survey this number had risen to over 42% (Keim et al.,
2008). Self-ligating brackets have a cap built in to the bracket itself to hold the wire in
position. First described in 1935, the Russell attachment was an early attempt to reduce
ligation time, increasing clinical efficiency (Stolzenberg, 1935). Claims of the Russell
attachment were that it offered up to a 50% reduction in chairside time (Read-Ward et al.,
1997). Various types of self-ligating brackets have been developed. Examples of self-
ligating brackets are shown in Table 1 (Harradine, 2008).
4

Various orthodontic appliance companies market their self-ligating bracket
systems to be faster, more efficient systems, using fewer appointments, and reducing
overall treatment time. There are two types of self-ligating brackets, active and passive.
Active self-ligating brackets have a spring clip that can press against the archwire, while
passive self-ligating brackets have a clip or a slide that theoretically does not press
against the wire. These brackets are only passive when the teeth are ideally aligned in all
dimensions, torque, angulation, and their in-out position, and when an undersized wire
that does not touch the walls of the bracket is being used. GAC‘s In-Ovation
®
R brackets
are an example of commonly used active self-ligating bracket. Other examples are
SPEED (Strite Industries, Cambridge, Ontario, Canada) and Time (Adenta GmbH,
Gliching, Germany). Some examples of commonly used passive self-ligating brackets
are the Damon bracket (Ormco, Glendora, CA), and SmartClip (3M Unitek, Monrovia,
CA).
There have been several studies that have shown a reduction in friction in self-
ligating brackets in vitro when compared with conventional brackets ligated with
elastomeric ties, and following this, the assumption that a reduction in friction translates
to a reduction in treatment time. Studies have also compared treatment efficiency (total
treatment time, number of appointments to complete treatment, and time required to
change archwires) between self-ligating brackets and conventionally ligated brackets in a
clinical setting. Others have studied treatment time, quality of treatment outcome, and
patient satisfaction in the two types of brackets. To date, the available clinical studies
offer some evidence that the use of self-ligating brackets increases clinical efficiency than
5

conventionally ligated brackets in terms of the requiring few number of appointment,
however, the majority of these studies examine passive self-ligating brackets, not active
self-ligating brackets (Eberting et al., 2001, Harradine et al., 2001, Yorita et al., 2007).
Findings from studies comparing passive self-ligating brackets with conventionally
ligated brackets cannot be related translated to passive self-ligating brackets (Rinchuse et
al., 2007). Therefore, the purpose of this study was to compare treatment time and
number of appointments between an active self-ligating bracket system and a
conventional twin edgewise bracket system.

6

Bracket Year
Russell Lock 1935
Ormco Edgelock 1972
Forestadent Mobil-Lock 1980
Forestadent Begg
Strite Industries SPEED
1980
1980
―A‖ Company Activa 1986
Adenta Time
―A‖ Company Damon SL
1996
1996
Ormco TwinLock 1998
Ormco/ ―A‖ Co Damon 2 2000
GAC In-Ovation
Gestenco Oyster
2000
2001
GAC In-Ovation® R 2002
Adenta Evolution LT
Ultradent OPAL
Ormco Damon 3
3M Unitek SmartClip
Ormco Damon 3 MX
Ultradent OPAL metal
Forestadent Quick
Lancer Praxis Glide
Class1/Ortho Organisers Carrière LX
2002
2004
2004
2004
2005
2006
2006
2006
2006
Table 1: Examples of self-ligating bracket designs (Courtesy of Harradine, 2008)
7

Chapter Two: Literature Review

I. History and Development of the Edgewise System
Early orthodontic appliances consisted of rigid framework to which teeth were
tied to so that they could be expanded into the arch form dictated by the framework. An
example of this is Pierre Fauchard‘s bandeau, an expansion arch made of a horseshoe-
shaped strip of previous metal to which teeth were ligated (Figure 1).

Figure 1: Fauchard’s bandeau

Most contemporary fixed orthodontic appliances are variations of the edgewise
appliance system, based on Edward H. Angle‘s early 20
th
century designs. Angle is
credited with developing four appliance systems, each one being an improvement of the
previous (Proffit, 3
nd
ed):

8

A. The E-Arch
The E-arch was Angle‘s first appliance, developed in 1900, and was an
improvement on the early orthodontic appliance (Figure2). It consisted of bands on the
molars and a heavy labial arch wire that extended around the arch. The end of the arch
wire was threaded and a small nut was placed on the threaded portion of the arch to allow
the wire to be advanced so that the arch perimeter increased. Teeth were ligated to the
heavy labial arch wire. This system delivered only heavy interrupted force.

Figure 2: Angle’s expansion E-arch (Courtesy of Steiner, 1933)

B. Pin and Tube
Because the E-arch was only capable of tipping teeth into a new positions, in
1910 Angle developed the pin and tube appliance (Figure 3). For this appliance, Angle
started to place bands on the other teeth and used a vertical tube on each band into which
a pin soldered to a smaller arch wire was placed. Tooth movement occurred by
repositioning the individual pins at each appointment and resoldering them into new
positions to gradually straighten the arch to idea. This appliance was impractical and
required a high degree of craftsmanship. Furthermore, the heavy base arch had poor
9

spring qualities and required many small adjustments, and the round arch did not control
root position.

Figure 3: The pin and tube appliance (Courtesy of Steiner, 1933)

C. Ribbon Arch
Angle developed the Ribbon Arch (Figures 4, 5, 6) in 1916 in his attempts to
achieve three-axis control of tooth movement. He modified the tube on the bands to a
vertically positioned rectangular slot. The appliance used a rectangular 0.036‖ x 0.022‖
gold arch wire held into the slots and held into place with pins. This appliance had good
spring qualities because the ribbon arch was smaller in the horizontal direction and
proved to be quite efficient in aligning malposed teeth. The weakness of this appliance
was that it did not provide good control of root position due to the resiliency of the ribbon
arch. Figure 6 (left) shows arch wires with the threaded arch ends and the friction sleeve
nuts that were inserted in the larger round end of tube to prevent the nuts from loosening
after being tightened. The pins shown to the right in Figure 6 held the ribbon arch in the
brackets.

10

Figure 4: The ribbon arch (Courtesy of Steiner, 1993)

Figure 5: The ribbon arch bracket (Courtesy of Steiner, 1933)

Figure 6: The basic elements of the ribbon arch appliance (Courtesy of Dewel, 1981)

D. Edgewise
In 1925 Angle developed the Edgewise appliance (Figure 7) to correct the
weaknesses of the ribbon arch. In this appliance, the slot on each band was reoriented
11

from vertical to horizontal. Rectangular brackets with gingival and occlusal wings were
soldered to the bands at the center of the labial surface and eyelets were soldered towards
the mesial and distal sides of the bands so that they could be tied to the arch wire for
rotational control (Figure 9). Figure 8 shows the various components of the edgewise
appliance. A rectangular wire ribbon arch wire was inserted into the slot after a ninety
degree rotation, on its ―edge‖, hence the name ―edgewise.‖ The dimension of the slot
was 0.022‖ x 0.028‖ and a similar size arch wire of precious metal was tied into the slots
with wire ligatures. This appliance moved teeth in all three planes of space
simultaneously. Modern appliances are based on this appliance.

Figure 7: The Edgewise arch (Courtesy of Steiner, 1933)

12

Figure 8: Edgewise paraphernalia (A) Wingless bracket on and off a band strip; (B)
the prototype of the modern bracket on and off a band strip; (C) A with an archwire
engaged; (D) with an archwire engaged; (E) various types of eyelets to be soldered on
the bands; (F) a ligature wire; (G) threaded washers, which were used as spacers.
(Kusy,Angle Orthod, 2002)

Figure 9: The edgewise arch bracket (Courtesy of Steiner, 1993)

13

II. The Modern Edgewise Appliance
The contemporary edgewise appliance retains the basic principle design of a
rectangular wire in a rectangular slot. In Angle‘s original edgewise appliance eyelets
were soldered to the corners of the bands so that separate ligature ties could be tied
through the eyelet to the arch wire to correct and control rotations. Rotation control in
the present day appliance is achieved by using twin brackets or single brackets with
extension wings. When steel arch wires replaced gold, the bracket slot size was reduced
from 0.022-inch to 0.018-inch slot, because steel wires of the same size was much stiffer.
Arch wires are tied to the bracket once placed in the slot with either steel ligatures
or elastomeric ligature ties (―o rings‖). In the 1970s elastomeric modules largely
replaced wire ligatures for a couple reasons. First, they are quicker and easier to place
and can be used in chains (power chain) to close spaces within an arch or prevent spaces
from opening (Profitt, 3
rd
ed). In the 1980s a bracket with a latching spring clip built into
the bracket, a self-ligating bracket, came to the orthodontic market (the SPEED bracket,
Orec Corp.). Theoretically these self-ligating brackets should provide less frictional
resistance to sliding than conventionally ligated brackets, as the clip holds the arch wire
in place without forcing it against the bottom of the bracket slot. The self-ligating
brackets can be made with a spring clip design or a sturdier rigid clip. However some
noticed disadvantages of the spring clip is that they may not hold a wire in place well
enough to deliver adequate moments to prevent tipping when closing loops are used, and
it may be difficult to closed rigid clips in full-dimension wires as full engagement is
necessary.
14

III. History and Development of Self-Ligating Brackets
In 1935 the first self-ligating appliance, the Russell attachment, was developed by
Dr. Jacob Stolzenberg, where a flat head screw fit into a circular opening on the face of
the bracket. With a small screwdriver, the screw can be loosened, making the system
more passive, or tightened, making it more active. Archwire changes were to be quick
and simple. Loosening allowed bodily translation on a round wire, while root torquing
was possible in a rectangular or square wire when tightening the screw. If an archwire
could not be fully engaged into the slot, the bracket had a vertical hole in the center to
allow a steel ligature to tie in the arch wire.

Figure 10: The Russell attachment in open and closed positions (Courtesy of Berger,
2000)

Dr. Stolzenberg reported later in 1946 that use of the Russell attachment resulted
in more comfortable treatment, shorter office visits, and shorter overall treatment time
(Stolzenberg, 1946).

15

Figure 11: The Russell attachment components (A) key to turn the nutl; (B) the
threaded nut; (C) the archwire; (D) hole in vertical center for ligature ties; (E) the slot
could hold a round wire up to 0.022 inch or rectangular wire up to 0.022in x 0.028
inch (Courtesy of Stolzenberg, 1935)

In 1971 Dr. Jim Wildman developed the Edgelok bracket, which was round with a
rigid labial sliding cap, in order to make the process of tying in archwires more efficient
(Wildman et al., 1972). The cap was closed over the archwire with finger pressure and a
special opening tool was used to slide the cap occlusally so the archwire could be inserted
in the slot. This bracket was the first passive self-ligating bracket as it transformed the
bracket slot into a tube that could loosely contain the archwire.

Figure 12: The Edgelok bracket in open and closed positions (Courtesy of Berger,
2000)
16

Two years later Dr. Franz Sander introduced the Mobil-lock bracket, which was
similar to the Edgelok bracket with a rigid clip design. A special tool to rotate the
semicircular labial disk into the open and closed position was required. Around the time
of the introduction of the Edgelok and the Mobil-lock, elastomeric ligatures were
introduced, and these brackets did not gain widespread use.
Dr. Herbert Hanson created the basic design of SPEED (Spring-loaded,
Precision, Edgewise, Energy, Delivery) bracket in 1976 that emerged on the market in
1980 after design refinement and clinical trials. The bracket has a curved, flexible
―Super-Elastic Spring Clip‖ that wraps occlusogingivally around a reduced size bracket
body (Berger 2000). The spring clip is flexible and holds the archwire in but also
contacts the archwire, making it an ―active‖ bracket, distinguishing itself from the other
self-ligating systems of its time. Dr. Hanson describes this as the ―homing action of the
spring‖, where the bracket reorients itself until the archwire is fully seated in the slot.
The slot is opened by moving the clip occlusally with a universal scaler at the gingival
aspect of the bracket or a curved explorer inserted into the labial window. The clip is
closed with finger pressure.

17

Figure 13: The SPEED™ bracket in open and closed positions (Courtesy of Berger,
2000)

Almost a decade later, in 1986, another self-ligating bracket came to the market.
Developed by Dr. Erwin Pletcher, Activa™ bracket had an inflexible curved arm that
rotated occlusogingivally around the cylindrical bracket body. This arm could be moved
into a ―slot-open‖ or ―slot-closed‖ position with finger pressure. The rigid arm converted
the slot into a tube, and as with the Edgelok bracket, the interaction between the slot and
the tube was limited, rendering the bracket ―passive. Since patients could easily open the
arm, this bracket lost its popularity.

Figure 14: The Activa™ bracket in open and closed positions (Courtesy of Berger,
2000)

18

In 1995, Dr. Wolfgang Heiser designed the Time™ bracket. It is the size of a
conventional bracket and has a rigid, curved arm that wraps occlusogingivally around the
labial aspect of the bracket. A special instrument is used to pivot the arm gingivally to
open the slot and occlusally to close it. The bracket clip is stiff and thus is a passive self-
ligating bracket.

Figure 15: The Time™ bracket in open and closed positions (Courtesy of Berger,
2000)

Creator of Edgelok, Dr. Jim Wildman also introduced the TwinLock™ bracket in
1998. The bracket has a flat, rectangular slide that sits between the tie wings of an
edgewise twin bracket. The slide can be moved occlusally to open the slot with a scaler
and gingivally with finger pressure to close the slide over the archwire in a passive
design.

19

Figure 16: The TwinLock™ bracket in open and closed positions (Courtesy of Berger,
2000)

In 1996 Dr. Dwight Damon introduced the Damon SL I bracket, where the slide
straddled the tie wing. Then, in 1999, the Damon SL II bracket, was developed, where
the slide lay between the tie wings. In both generations of Damon brackets, the slide
moves incisally on the maxillary brackets and gingivally on the mandibular brackets,
requiring special pliers to move the slide. These brackets are passive SL brackets.

A B C
Figure 17: The Damon™ SL I bracket in open (A) and closed positions (B) (Courtesy
of Berger, 2000),
Damon™ SL II bracket (C) (Courtesy of Ormco Inc.)

In-Ovation
®
R, an active self-ligating bracket, was introduced in 2002 (Figure
18). It features a clip that is Interactive™ and provides both passive and active control of
the archwire. In smaller, round wires, the bracket is passive for the leveling and
20

alignment phase of treatment. It becomes expressive in square or small rectangular
archwires, where torque is beginning to be expressed. The bracket becomes active in
larger sized rectangular archwires for detailing and finishing (Figure 19).

Figure 18: The In-Ovation
®
R bracket (Courtesy of GAC International, Inc.)

Figure 19: The In-Ovation
®
R bracket (Courtesy of GAC International, Inc.);
left, passive state with smaller round archwire; center, expressive state with
square or small rectangular archwires; right, active state with a large
rectangular archwires

3M Unitek introduced a self-ligating bracket, SmartClip™, in 2002. This bracket
is distinct from other self-ligating appliances in that it does not have slide or a arm to
open and close the slot. Instead, the archwire is pushed into and out of the slot as it
21

passes through nickel-titanium clips on the mesial and distal of the bracket. This is done
with a special plier made for this action.

Figure 20: The Unitek SmartClip™ bracket (Courtesy of 3M Unitek Inc.)

IV. Types of Orthodontic Ligation
There are various methods to tie in archwires into brackets. Some examples are:
steel ligatures ties, elastomeric ties (O-rings), and brackets with built-in sliding gates or
clips. These methods have their own advantages and disadvantages. Steel ligatures have
been used to tie archwires into bracket slots since the start of the edgewise technique of
orthodontics. The advantages of steel ligatures are that they retain their shape and do not
stretch or fatigue, they do not absorb bacteria from the oral environment, and they do not
adhere plaque as easier, and are thus more hygienic than elastomeric ligatures
(Türkkahraman et al, 2005). The bracket-archwire interaction when using steel ligatures
is dependent on how tightly the ligatures are tied around the bracket (Ridley et al., 1979).
Steel ligatures have been shown to produce a reduced amount of friction between the
archwire and bracket when loosely tied around the bracket (Hain et al, 2003 AJODO,
22

Bednar et al., 1991). The greatest disadvantage of steel ligature ties is the time it takes to
tie in an archwire. Studies have shown that significantly more time is taken to tie an
archwire with steel ties compared with other methods (Maijer et al., 1990, Shivapuja et
al., 1994, Berger et al., 2001, Paduano et al., 2008). Furthermore, steel ligatures are
twisted and cut and if not properly tucked in can cause irritation to the oral tissues.
Elastomeric ligature ties were introduced in the 1970s and due to the ease of use
have become popular since. The advantages of the elastomeric ties are that compared to
stainless steel ligature ties, they are faster to untie and tie (Shivapuja et al., 1994,
Paduano et al., 2008) the archwire into the bracket and can be used in the form of a chain
to close spaces or slide teeth along the archwire (Ash et al., 1978). The disadvantages of
elastomeric modules are that they demonstrate a rapid rate of decay and deformation and
are often associated with poor oral hygiene as they adhere more plaque and bacteria than
steel ligatures.
Self-ligating brackets do not require the use of elastomeric or steel ligature ties to
tie the archwire into the bracket, as there is a built-in clip or slide that is attached to the
bracket itself. The advantages of these brackets are they require the least amount of time
for archwire removal and insertion, compared to ligation with stainless steel ligature ties
and elastomeric ties (Shivapuja et al., 1994 and Berger et al., 2001, Turnbull et al., 2007,
Paduano et al., 2008, Harradine et al., 2001). Another benefit of self-ligating brackets is
that their use does not require a chairside assistant to pass the ligatures to the operator
during ligation. Also, it is possible that with repeated use the stiffness of the gates
23

stiffness may be lost, which can result in inadequate bracket engagement (Pandis et al.,
2007).

V. Friction in Orthodontics
In orthodontics tooth movement is accomplished by moving teeth with brackets
attached to them along the archwire. As the bracket moves along the archwire, friction
opposes this movement. Friction is the force resisting the motion of a body relative to
another and is opposite the direction of the motion. According to Read-Ward et al.
(1997) friction is affected by a number of factors. The direction and magnitude of the
relative motion between the surfaces in contact has an effect. Secondly, the load applied
to the surfaces in contact can increase friction. An example of this is the type of
orthodontic ligation. Next, the temperature of the environment and the presence of
lubricants also can affect the amount of friction. In addition the condition of surfaces in
contact can influence the friction. For example, friction can be increased when there is
plaque or calculus on the arch wire. The property of the material used can affect friction.
The use of a nickel-titanium wire, a stainless steel wire, or a beta-titanium wire can
change the dynamics of friction between the surfaces. The angulation that the bracket
and the archwire contact each other also influences friction (Kusy et al., 1997). The
position of the tooth and thus the bracket slot changes the angle that the bracket and the
archwire come into contact with one another. The dimension of the slot also affects
frictional forces. As the mesio-distal width of the bracket increases, friction increases,
while as the occluso-gingival dimension increases friction decreases. The dimension and
24

shape of the archwire affects friction—archwires that have larger cross-sectional
dimensions create more friction; rectangular wires create more friction than round wires
(Kusy et al., 1999). Repeated use of brackets also increase friction, this is due to surface
roughness of the bracket slot which causes mechanical interlocking at the bracket-
archwire interface (Kapur et al., 1999).

IV. Self-Ligating Systems
A. Ligation Time
An advantage of self-ligating brackets is decreased chairtime in the office.
Archwire changes are generally faster with the use of self-ligating brackets. Several
investigators have studied the difference between ligation time in self-ligating brackets
and conventionally ligated brackets. In a prospective clinical study, Turnbull et al.
assessed the speed of archwire changes in between self-ligating brackets and
conventional brackets tied with elastomeric ties. The study found that ligation time in
self-ligating brackets was approximately twice as quick as the conventional brackets
(Turnbull et al, 2007). Other researchers have also examined the time savings for
archwire changes between self-ligating brackets and elastomeric ties and found a
significantly reduced amount of time for archwire changes with self-ligating brackets
(Paduano et al., 2008). In another study researchers found that the time savings to
remove archwires in self-ligating brackets compared to conventional brackets tied with
elastomeric ties was an average of half a minute, while tying in the archwire saved an
average of over a minute (Shivapuja et al., 1994). Harradine (2001) found that the self-
25

ligating brackets required an average of nine seconds less time to close the passive self-
ligating bracket slides than to ligate the conventional brackets, which were tied with
mostly elastomeric ligature ties and a few stainless steel ligature ties. A single archwire
required an average of 16 seconds less time to open than to remove the conventional
ligatures. Harradine noted the reduced need for chairside assistance with self-ligating
brackets, but concluded that time savings during archwire ligation and removal was
modest and not of clinical significance, though it was statistically significant. Studies
have also examined the time difference in archwire changes with self-ligating brackets
compared to that in conventionally ligated brackets tied with steel ligatures. Shivapuja et
al. (1994) found that time saving for opening self-ligating brackets compared to removing
conventional brackets tied with steel ligatures were an average of more than two and a
half minutes in a single arch. Closing self-ligating brackets compared with tying steel
ligature ties on conventional brackets was found to save up to an average of almost five
minutes in one arch and can be up to a twelve-minute time savings. Other studies have
found that that self-ligating brackets can offer chairtime savings of up to four times as
less compared to wire ligation of conventional brackets (Maijer et al., 1990, Voudouris,
1997).

26

B. Friction
The design of self-ligating brackets, where the slot is closed off by a metal gate or
clip, theoretically should provide a friction-less tube for the archwire to sit in, more so
when smaller archwire sizes are used in treatment. Studies evaluating friction in various
self-ligating brackets compared with conventional brackets have been conducted.
Several researchers have demonstrated low friction levels with self-ligating
brackets compared with friction levels of conventional brackets used with elastomeric
modules (Shivapuja et al., 1994, Thorstenson et al., 2001, Sims et al., 1993, Kapur et al.,
1998, Pizzoni et al., 1998, Thomas et al., 1998, Taylor et al., 1996, Tecco et al., 2005,
Berger et al., 1990, Khambay et al, 2004, Cacciafesta et al., 2003, Redlich et al., 2003,
Reicheneder et al., 2008, Petersen et al., 2009). In these studies investigators examined
both passive and active self-ligating brackets and found that self-ligating brackets exhibit
significantly less friction than conventional brackets tied with elastomeric ties. Petersen
et al. (2009) found that up to 50% of the local alignment force was lost due to frictional
resistance. They also examined the difference in alignment force in fatigued or stretched
elastomeres and found that the frictional forces were not statistically different from the
forces present in self-ligating systems. These results confirmed the findings of Taylor et
al. (1996), who, in an in vitro study, examined conventional brackets tied with stretched
elastomeric ties and found reduced friction over time as the elastic module had been in
place and worn. Sims et al. (1993) found that elastomeric ties in the ‗figure-of-eight‘
form show a 70-220 per cent increase in friction compared to conventional elastomeric
ties. Elastomeric ties in any form produce more friction than self-ligating brackets.
27

Other studies have compared stainless steel ligature-tied conventional brackets
(Read-Ward et al 1997, Shivapuja 1994, Thorstenson et al, 2001, Taylor et al 1996)
versus self-ligating brackets and have shown significantly less friction with self-ligating
brackets. Thorstenson et al. (2001) found that self-ligating brackets in with the gates
open, ligated with steel ties and conventional brackets, ligated with steel ties had similar
frictional forces. Closed self-ligating brackets in the conditions studied had less friction
than conventional brackets tied with steel ties. Loosely-placed steel ligatures on
conventional brackets reduces friction, with a greater reduction on round wires compared
to rectangular wires (Taylor et al, 1996). Shivapuja et al. (1994) demonstrated that wire
ligatures produce 30-50 per cent of the frictional forces as elastomeric ties.
Researchers have also compared friction in passive self-ligating brackets and
active self-ligating brackets and found that passive self-ligating brackets exhibit reduced
friction compared to active (Krishnan et al 2009, Budd et al, Pizonni et al 1998, Thomas
et al 1998, Thorstenson et al., 2002, Taylor et al, 1996, Redlich et al., 2003, Tecco et al.,
2007) Thorstenson et al. (2001) concluded that active self-ligating brackets had more
resistance to sliding than passive self-ligating brackets but did so at the loss of control.
Redlich et al. (2003) found that the active self-ligating brackets used in their study
actually had more friction than the conventional brackets tied with elastomeric ties, while
the passive self-ligating brackets had the least amount of friction. Tecco et al. (2007)
examined friction in various archwire-bracket combinations using different sizes and
materials of archwires in active and passive self-ligating brackets and also in
conventional brackets tied with elastomeric ligatures and Slide
©
ligatures, which are
28

similar to elastomeric ligatures but with an anterior part that is more rigid, simulating
self-ligation. The self-ligating brackets generated the least amount of friction compared to
the convention. Researchers found that there is no one type of bracket that consistently
had the lowest friction in all archwire sizes and materials. Friction was dependent on the
combination of archwire material (stainless steel, nickel-titanium (NiTi), or beta-
titanium) and size. They found no difference in friction in rectangular beta-titamium
wires in any of the groups tested and in the round NiTi wire tested the passive self-
ligating bracket had the least amount of friction. In the smaller rectangular NiTi archwire
both active and passive self-ligating brackets h ad lower friction than the conventional,
and in the larger rectangular stainless steel or NiTi wires, the Slide
©
ligature-tied
conventional bracket had significantly less friction than all other brackets. This study
suggested that in smaller archwire sizes, the self-ligating brackets generated less friction
than the conventional brackets. Budd et al. (2008) compared frictional characteristics of
three different manufacturers of active self-ligating brackets and one passive self-ligating
bracket in vitro and found that the passive self-ligating bracket demonstrated the lowest
frictional resistance to sliding compared to the three types of active self-ligating brackets,
concluding that the primary cause for this was the active versus passive self-ligation
design. Krishnan et al.‘s (2009) findings support this study. They found that frictional
forces were lower in the passive and active self-ligating brackets compared with the
conventional brackets and between the active and passive self-ligating brackets in nickel-
titanium and beta-titanum wires frictional forces were lower in the passive self-ligating
brackets, while there was no difference in stainless steel wires.
29

C. Alignment Effectiveness
The lower frictional forces found in self-ligating brackets theoretically should
increase alignment efficiency, as unloading forces are increased in self-ligating brackets
(Petersen et al., 2009).
Studies on efficiency of alignment have been conducted comparing both active
self-ligating brackets with conventional brackets and passive self-ligating bracket
compared with conventional brackets. In the studies comparing passive self-ligating
brackets with conventional, researchers have found no significant difference in the
alleviation of crowding between the two bracket types (Pandis et al, 2010, Miles et al
2006, Miles et al., 2005, Scott et al., 2008, Fansa et al., 2009) Researchers also found no
significant difference in alignment efficiency between active self-ligating brackets and
conventional brackets (Fansa et al., 2009, Pandis et al., 2010, Miles, 2005, Fleming et al.,
2009). However, in one study by Pandis et al. (2007) the researchers found that with
moderate crowding, passive self-ligating brackets were 2.7 times faster at alleviating
crowding than the conventional brackets.
Fansa et al. (2009) compared the effectiveness of leveling in various active and
passive self-ligating brackets with conventional brackets in alignment in vitro and after
examining the force levels and torque movement, they found that self-ligating brackets
are not more effective in leveling than conventional brackets.
In another study examining alignment efficiency, Pandis et al. conducted a
randomized controlled trial using inclusion and exclusion criteria compared the treatment
time required to complete the alignment of crowded maxillary anterior teeth (canine to
30

canine) between a passive self-ligating bracket and an active self-ligating bracket. They
found that there was no significant difference in crowding alleviation between the two
types of self-ligating brackets systems and concluded that the use of passive or active
self-ligating brackets does not seem to affect treatment duration for alleviating initial
crowding (Pandis et al., 2010).
In an in-vivo study, Miles (2005) compared effectiveness of alignment in passive
self-ligating brackets and conventional brackets using the irregularity index. The results
indicated that the passive self-ligating bracket was no more effective in reducing
irregularity than conventional twin brackets ligated with elastomeric ties or steel ligature
ties. The author noted that self-ligating brackets demonstrate low frictional resistance
only up to certain archwires, depending on the size of the bracket slot.

D. Treatment Time and Number of Appointments
With the findings of decreased friction in self-ligating bracket systems, it may be
expected that treatment time would be reduced when using self-ligating brackets. There
are several studies that examined treatment time differences between self-ligating
brackets and conventional brackets.
Hamilton et al. retrospectively evaluated total treatment time and number of
appointments in 762 consecutively treated patients, 383 treated with a conventional pre-
adjusted bracket system and 379 treated with active self-ligating brackets. The
investigators found that there was no statistically significant difference between the
overall treatment time or the number of appointments between the two bracket systems,
31

but found that the number of debonded brackets and emergency visits was significantly
higher in patients treated with active self-ligating brackets. Since there was no inclusion
criteria for this study, various types of orthodontic cases were included in this study,
which incorporates a number of variables that could have affected the results of the study.
Hamilton et al. concluded that active self-ligating brackets appear to have no measurable
advantages in orthodontic treatment time, number of treatment visits, and time spent in
initial alignment when compared with conventional brackets (Hamilton et al., 2008).
Other available studies comparing treatment time and number of appointments in
self-ligating brackets and conventional brackets have been conducted on passive self-
ligating bracket systems. Eberting et al. (2001) studied the effectiveness and efficiency
of a passive self-ligating bracket compared to conventional brackets ligated with either
steel or elastomeric ligatures. The authors assessed treatment time, number of
appointments, and the quality of the treatment outcome, using the American Board of
Orthodontics (ABO) grading criteria. They furthermore, conducted a survey of the
patients used in the study finding that the patients treated in passive self-ligating brackets
perceived their treatment time as being shorter than expected. These patients had
significantly lower treatment times (average of six fewer months), required significantly
fewer appointments (average seven fewer visits) and had significantly higher ABO scores
(indicating a nicer treatment outcome) than those treated with conventionally-ligated
edgewise brackets (Eberting et al., 2001). In 2001 Harradine studied treatment efficiency
in a passive bracket system compared to a conventional pre-adjusted appliance system.
The author examined cases that he treated--thirty consecutively finished cases treated
32

with the passive self-ligating bracket, compared with thirty matched cases treated in
conventional brackets. Harradine found that the passive self-ligating cases required an
average of four fewer months and four fewer visits to be treated to an equivalent level of
occlusal regularity as measured by the Peer Assessment Rating (PAR) scores. Each pair
of cases had: the same incisor classification of malocclusion, age at the start of treatment
within three years if below 18 years of age and within ten years if above 18 years of age,
PAR scores at the start of treatment differing by eight or less, similar extraction patterns,
and cases with palatally ectopic canine teeth or involved orthognathic surgery were
matched for these features. The results were statistically significant. The author did not
utilize inclusion or exclusion criteria but merely compared consecutive cases, thus, this
study included cases that were of various difficulty levels (Harradine, 2001).
In an IADR abstract, Yorita et al. (2007) found that the use of passive self-ligating
brackets results in a fewer number of appointments, but does not shorten treatment time
when compared to conventional brackets.
In another recent IADR abstract Greenlee et al. (2010) conducted a systematic
review of literature to assess the efficiency, effectiveness, and stability of treatment using
self-ligating brackets, as compared to conventional brackets. Investigators found that
there were no significant differences in treatment time with the use of self-ligating
brackets. Shortened chair time and slightly less incisor proclination were the only
significant advantages found in the current literature.

33

E. Patient Comfort
Several manufacturers of self-ligating brackets market the use of self-ligating
brackets to be a less painful experience than conventionally ligated brackets. Fleming et
al conducted a systematic review of randomized controlled trials and controlled clinical
trials to evaluate significant differences between self-ligating brackets and conventional
brackets. Meta-analysis of the influence of bracket type on subjective pain experience
did not demonstrate a significant advantage for neither the self-ligating nor the
conventional appliance (Fleming et al., 2010). In Fleming et al.‘s 2009 study researchers
compared subjective pain experience during the first week after initial placement of a
passive self-ligating appliance and conventional brackets and found no difference. In
terms of archwire insertion and removal, they found increased patient discomfort for the
self-ligating appliance. Other research comparing passive self-ligating brackets with
conventional brackets did not find any statistically significant difference in perceived
discomfort levels during initial tooth alignment (Scott et al, 2008). Miles et al. (2006)
found that during intial alignment the passive self-ligating bracket studied was less
painful but substantially more painful when placing the second archwires. Some studies
report a significantly lower mean pain intensity during treatment with passive self-
ligating brackets (Pringle et al., 2009).

F. Hygiene
Often manufacturers market self-ligating brackets to be more hygienic. One study
(Pandis et al., 2010) demonstrated that salivary Streptococcus mutans is not significantly
34

different between patients in conventional and self-ligating brackets. They found that
pre-treatment levels of S. mutans is a significant predictor of S. mutans levels after
appliances are placed, though this is not the case for total bacterial counts. Another study
found no difference in occurrence of white spot lesions between self-ligating brackets and
conventional brackets and noted that lesions depend on the patient‘s oral hygiene status,
not the type of bracket used (Polat et al, 2008). Türkkahraman et al. (2005) studied
changes in microbial flora and periodontal status after placement of orthodontic brackets
in a split mouth design comparing elastomeric ligatures and steel and found that though
teeth ligated with elastomeric rings showed slightly more microorganisms than teeth
ligated with steel ligatures, the difference was not statistically significant. The
researchers stated that use of elastomeric ties in patients with poor oral hygiene is not
recommended. Some studies have found reduced bacteria levels on teeth with self-
ligating brackets compared with teeth bonded with conventional brackets tied with
elastomeric ties, concluding that self-ligating appliances promote reduced plaque
retention (Pelligrini et al., 2009). In evaluation of the periodontal status, researchers have
found no advantage with self-ligating brackets compared to conventional brackets
(Pandis et al, 2008).

35

Chapter Three: Hypothesis

Research Hypothesis, H
a
:
1. Treatment time is significantly shorter for cases treated with active self-
ligating In-Ovation® R brackets than for cases treated with conventionally ligated
brackets.
2. The total number of appointments required to complete orthodontic treatment
is significantly fewer for cases treated with active self-ligating In-Ovation® R brackets
than those treated with conventionally ligated brackets.

Null Hypothesis, H
0
:
1. There is no significant difference in overall treatment time between cases
treated with active self-ligating In-Ovation® R brackets and cases treated with
conventionally ligated brackets.
2. There is no significant difference in the total number of appointments required
to complete orthodontic treatment between cases treated with active self-ligating In-
Ovation® R brackets and cases treated with conventionally ligated brackets.

36

Chapter Four: Materials and Methods

This study was approved by the University of Southern California Health
Sciences Institutional Review Board (HSIRB). The IPB approval ID is UP-09-00221.
The sample was selected from orthodontic patients treated in a private practice in
Southern California with either active self-ligating
The sample was selected from orthodontic patients treated in a private practice in
Southern California with either active self-ligating (N=58) or conventionally ligated twin
edgewise brackets (N=44). The active self-ligating brackets used by the orthodontist was
In-Ovation® R brackets (GAC Intl, Bohemia, NY, USA). The conventionally ligated
brackets used for treatment were metal twin brackets from American Orthodontics
(Sheboyaga, WI, USA). Both the self-ligating and conventionally ligated brackets are
018 slot Roth prescription. The sample consisted of Caucasian females who were at least
11 years of age. The In-Ovation® R self-ligating and the conventionally ligated patients
were selected according to inclusion and exclusion criteria. In-Ovation
®
R self-ligating
cases in this particular private practice were cases that were started after May of 2002
when the orthodontist had completed transitioned all of his new starts to the In-Ovation
®

R self-ligating appliance. Prior to using the In-Ovation
®
R active self-ligating brackets,
the orthodontist was using a passive self-ligating appliance system. Cases selected for
the conventionally ligated bracket group were cases that were started prior to June 1997,
when the orthodontist was using only conventionally ligated brackets. Patient treatment
37

records were accessed. The treating orthodontist in the private practice is an ABO
diplomate, university faculty, and has been practicing orthodontics for 38 years.
Inclusion criteria were: same ligation method, molar classification, overjet, overbite,
maxillary anterior crowding, and mandibular anterior crowding.

Inclusion Criteria:
The inclusion criteria for case selection were the following:
1. Gender: female
2. Ethnicity: Caucasian
3. Age: 11-25 years of age
4. Treatment type: non-extraction
5. Same ligation method: treatment by the same orthodontist with the same ligation
method for entirety of treatment
6. Molar classification: Angle class I
7. Overjet: 1-4mm
8. Overbite: 0-5mm
9. Maxillary crowding: 0-6mm
10. Mandibular crowding: 0-6mm

Exclusion Criteria:
The criteria for exclusion were the following:
38

1. Expansion: treatment involving any expansion appliance (maxillary or
mandibular)
2. Extraoral appliances: treatment involving use of an extraoral traction appliance
3. Functional appliances: treatment involving use of a functional appliance
4. Impacted teeth: patients with impacted teeth
5. Surgery: treatment involving surgical treatment
6. Asymmetry: treatment involving skeletal asymmetries
7. TMJ dysfunction: patients who had symptomatic TMJs prior to treatment or
during treatment and required TMJ therapy
8. Parafunctional habits: patients with parafunctional oral habits
9. Skeletal open bite
10. Two-phase treatment: patients who had more than one orthodontic treatment
11. Craniofacial anomalies: patients who had a craniofacial development deformity
(ie cleft palate)
12. Retreatment: patients who have already had previous orthodontic treatment
13. Extractions: patients whose treatment involved the extraction of teeth
14. Transfer patients: patients who were transferred into the practice after treatment
was started elsewhere
15. Partial treatment: patients who did not have appliances placed on all their teeth
(i.e. treatment with removable retainers only or brackets or bands on only anterior
teeth)
39

16. Removable appliance treatment: patients who were treated with Invisalign or
other removable appliances only

Data Collection:
Using patient treatment records the following information was obtained and
calculated:
1. Age at the start of treatment
2. Gender
3. Race
4. Amount of pre-treatment overjet
5. Amount of pre-treatment overbite
6. Amount of maxillary crowding
7. Amount of mandibular crowding
8. Banding date
9. Debanding date
10. Treatment time in months
11. Number of appointments to complete treatment, including emergencies,
excluding appointments to place separators
12. Number of missed appointments
13. Number of broken brackets
14. Number of emergency appointments

40

Data Grouping:
All cases selected were divided into the following 2 groups:
1. In-Ovation®R self-ligating (I)
2. Conventionally ligated (C)

Assumptions:
As there are various factors that could potentially influence the rate of orthodontic
tooth movement, this study was based on the following assumptions:
1. The biological differences in the rate of tooth movement due to orthodontic
forces are controlled for by the race and age of the sample.
2. The treatment protocol (archwire sequence, treatment mechanics, etc) is
similar in the 2 groups (In-Ovation
®
R and conventional).
3. Differences in treatment mechanics among patients do not significantly affect
treatment duration.
4. All the cases examined in this study are finished similarly with respect to
dental irregularities and quality of finish.
5. The inclusion criteria for case selection is adequate in limiting confounding
variables to influence overall treatment time and the number of appointments
to complete orthodontic treatment.
6. The protocol used for this study is appropriate and reproducible.

41

Statistical Analysis:
All data were recorded in Microsoft Excel worksheets and were analyzed using
Excel.
Descriptive statistics were examined to identify outliers and to assess the
distribution. Independent t-tests (two-sample assuming equal variances) were performed
to compare the two groups. Significance was established at alpha = 0.05. Outliers were
removed from the data set.

42

Chapter Five: Results
The collected data were analyzed and the descriptive statistics are summarized in
table 9 in Appendix A. The data consisted of 58 In-Ovation® R self-ligating cases and
44 conventionally ligated bracket cases.
Number of Cases
In-Ovation
®
R 58
Conventional 44
Table 2: Distribution of selected cases by bracket type
The means, standard deviations, and p-values for the number of appointments,
overall treatment time, age, emergency appointments, number of broken brackets, and
missed appointments were calculated for the In-Ovation
®
R and conventionally ligated
cases, and these results are summarized in tables 3-8 and figures 22-25.
# Appointments
(Mean ± SD)
p-value
In-Ovation
®
R 17.52±2.897
(range 11-25)

<0.001

Conventional 26.48±4.417
(range 17-35)
Table 3: Comparison of number of appointments in In-Ovation
®
R and conventional
groups

43

Treatment Times
(Mean ± SD)
p-value
In-Ovation
®
R 25.19±3.868
(range 11-36)

0.18

Conventional 24.1±3.874
(range 13-34)
Table 4: Comparison of treatment time In-Ovation
®
R and conventional groups

Age
(Mean ± SD)
p-value
In-Ovation
®
R 12.82±1.580
(range 11-17)

0.16

Conventional 13.46±2.967
(range 11-24)
Table 5: Comparison of age in In-Ovation® R and conventional bracket groups

44

Emergency Appointments
(Mean ± SD)
p-value
In-Ovation
®
R 2.02±1.550
(range 0-7)

0.08

Conventional 1.43±1.731
(range 0-7)
Table 6: Comparison of number of emergency appointments in In-Ovation
®
R and
conventional groups

Broken Brackets
(Mean ± SD)
p-value
In-Ovation
®
R 1.78±1.623
(range 0-7)

0.09

Conventional 2.43±2.556
(range 0-9)
Table 7: Comparison of number of broken brackets in In-Ovation
®
R and conventional
groups

45

Missed Appointments
(Mean ± SD)
p-value
In-Ovation
®
R 0.67±0.962
(range 0-4)

0.06

Conventional 1.07±1.149
(range 0-4)
Table 8: Comparison of number of missed appointments In-Ovation
®
R and
conventional groups

Figure 21: Mean number of total appointments for In-Ovation
®
R and conventional
group

0
5
10
15
20
25
30
In-Ovation R Conventional
17.5
26.5
Number of Total
Appts
Bracket Type
46

Figure 22: Mean treatment times for In-Ovation® R and conventional group

Figure 23: Mean age for In-Ovation
®
R and conventional group
0
5
10
15
20
25
30
In-Ovation R Conventional
25.2
24.1
Treatment
Time
(months)
Bracket Type
0
5
10
15
In-Ovation R Conventional
12.82
13.46
Age (years)
Bracket Type
47

Figure 24: Mean number of emergency appointments for In-Ovation
®
R and
conventional group

Figure 25: Mean number of broken brackets for In-Ovation® R and conventional
group
0
1
2
3
In-Ovation R Conventional
2.02
1.43
No. of
Emergency
Appts
Bracket Type
0
1
2
3
In-Ovation R Conventional
1.78
2.43
No. of
Broken
Brackets
Bracket Type
48

Figure 26: Mean number of missed appointments for In-Ovation
®
R and conventional
group

Independent sample t-tests for number of appointments demonstrated statistically
significant differences between the In-Ovation
®
R cases and the conventionally ligated
cases at the 95% confidence interval (p<0.001) for number of appointments. Appendix B
shows the results of these statistical analyses. However, independent sample t-tests for
the treatment times between the two groups did not show any significant differences
between the In-Ovation
®
R cases and the conventionally ligated cases at the 95%
confidence interval (p=0.176).
To test whether the data is normally distributed histograms for number of
appointments and treatment times were generated for both In-Ovation
®
R and
conventionally liagated cases. Figures 27-29 in Appendix B shows the distribution of
these variables.
0
1
2
3
In-Ovation R Conventional
0.67
1.07
No. of
Missed
Appts
Bracket Type
49

Independent sample t-tests revealed the following results between the In-Ovation
®

R and conventional bracket groups:
1. No significant differences were found for treatment times
2. A significant difference was found for total number of appointments. On average,
the In-Ovation
®
R cases required 6.62 fewer appointments than the conventional
cases, a significant difference at the 95% confidence interval.
3. No significant differences were found in the age of the patients.
4. No significant differences were found in the number of emergency appointments.
5. No significant differences were found in the number of broken brackets.
6. No significant differences were found in the number of missed appointments.

50

Chapter Six: Discussion

The manufacturer of In-Ovation
®
R makes claims directly to the public that the
use of these brackets results in less treatment time, fewer appointments, less chairtime,
fewer adjustments, reduced discomfort, and a more attractive smile. The public is
subjected to the advertisements of these companies with no supporting evidence given to
them; they are uninformed. In most cases, the public will not investigate whether these
claims are in fact true or not, and furthermore, oftentimes do not have access to resources
to verify statements made by the companies. Therefore, studies like this current one
should be conducted to evaluate whether the claims of these orthodontic appliance
manufacturers are in fact accurate or not, with the hopeful end result being that false
statements made direclty to the public will not be made.
The primary objective of this study was to evaluate treatment data from patients
who had orthodontic treatment with metal active self-ligating brackets, In-Ovation
®
R,
and those who had treatment with metal conventionally ligated brackets. We
hypothesized that overall treatment time required to complete orthodontic treatment for
the In-Ovation
®
R cases would be less than for the conventional cases, and that the total
number of appointments required to complete orthodontic treatment for the In-Ovation
®

R cases would be fewer than for the conventional cases.

51

Sample Analysis
The sample was collected from a private orthodontic practice according to
specific pre-determined inlcusion and exclusion criteria (see Materials and Methods
section). The cases included in this study were Caucasian females with Angle class I
malocclusions that had nonextraction orthodontic treatment. Appendix A demonstrates
the descriptive statistics. In order to limit as many confounding variables as possible,
various inclusion criteria was used to select cases for this study. The number of
conventional cases in this study were much fewer than the In-Ovation
®
R cases. This is
due to the fact that years ago, when the orthodontist was using conventional brackets, for
the type of case this study was seeking (Caucasian female, single phase, non-extraction,
Angle class I malocculsion, no extraoral or functional appliances used) most often partial
treatment was done. Since this study required cases to be treated with appliances on at
least first molar to first molar appliances in both arches, cases that had partial treatment
were not selected for this study, ruling out many cases that may have better matched the
self-ligating bracket sample. It should be noted that the sample of conventionally ligated
cases were all treated when the orthodontist had anywhere from 3-25 years of experience,
while the orthodontist had 30-37 years of working experience when treating the self-
ligating bracket cases. Retrospective studies such as this one are potentially biased as it is
unclear which variables were controlled and which were not (Rinchuse et al., 2005).
Furthermore, observer bias may have affected the results if the orthodontist unknowingly
treats differently due to the excitement of using a new appliance. A better study design
52

would have been to do a prospective study where the orthodontist uses both appliances
during the same time period to rule out the variable of practitioner experience.

Treatment Outcomes
All cases selected for this study were treated by the same orthodontist in a private
practice setting. Therefore, throughout this study it is assumed that the treatment
outcomes of the selected cases are comparable. Whether the selected cases were actually
treated to similar occlusal and dental relationships was not investigated. There was no
initial or final dental irregularity index (PAR or ABO) used. This assumption is central
to this study, and results and conclusions could be discounted if this assumption is not
satisfied. Caution must be used in interpreting the results and generalizing conclusions
formulated based on the results of this study.
In Harradine‘s study(2001), for case matching criteria, the investigator used initial
and final PAR scores to assess case complexity and quality of treatment. In addition,
Eberting et al.‘s sample demonstrated higher ABO scores for the cases treated with the
passive self-ligating bracket compared with those treated by the conventionally ligated
bracket (Eberting et al., 2001).

53

Significance of the Findings
1. Treatment Time
Summarized in Table 4, one of the main topics of this study is to examine the
overall treatment time required to complete orthodontic treatment in two groups, an
active self-ligating bracket group (In-Ovation
®
R) and a conventionally ligated bracket
group. On average, In-Ovation
®
R cases were completed in 25.19 months, while
conventional bracket cases were completed in 24.14 months. There was no statistically
significant difference in treatment times between the two groups. The results of this
study coincide with those reported in the literature for a similar study comparing active
self-ligating brackets with conventionally ligated brackets (Hamilton et al., 2008), and
with those studies comparing passive self-ligating brackets with conventionally ligated
brackets (Yorita et al., 2007, Greenlee et al, 2010). However, the results of this study
also differ from some studies comparing treatment time in cases treated with passive self-
ligating bracket with conventionally ligated brackets (Eberting et al., 2001, Harradine,
2001). Harradine‘s study sample included a wide variety of cases, as the researcher
included thirty consecutively finished passive self-ligating cases and matched them with
cases treated in conventional brackets. Harradine included hypodontia cases, ectopic
canine cases and orthognathic surgery cases, and results showed that the passive self-
ligating cases finished an average of four months shorter than the conventional bracket
cases with similar dental irregularity scores (PAR scoring system). Furthermore, a reason
for the differing results could due to differences in the type of self-ligating bracket
studied, passive versus active.
54

In this study, conventional bracket cases were completed in 24.14 months.
Compared to Hamilton et al.‘s study (2008) this was much longer. Hamilton et al. found
that conventional cases finished in an average of 15.9± 6.1 months. A possible reason for
shorter treatment times in Hamilton et al.‘s study was that the treatment time did not
inlcude any initial treatment carried out on the class II and nonextraction malocclusions
in both groups with the Herbst or pendulum appliances. When these appliances were
used, a period of settling occurred before placing the fixed appliances. Essentially,
Hamilton‘s study may have included multiple cases that had an initial phase of treatment,
which was not included in the recorded duration of treatment. In Harradine‘s study
(2001), treatment duration for the conventional group was 23.5 ± 5.16 months. The
conventionl group in Eberting et al.‘s study (2001) had an average treatment time of
30.87± 7.85 months. Skidmore et al. (2006) found that average treatment time for class I
malocclusion was 21.9± 4.6 months and for nonextraction cases was 21.3 ± 4.4 months.
The average treatment duration for the conventional group in this current study was 24.14
months, which is comparable to the treatment duration of most of the previous studies for
the conventional group, as it falls within one standard deviation from the mean found in
those studies.
It is important to note that, unlike this current study, these previous studies did not
utilize struct inclusion criteria and included Class II and III malocclusion, extraction,
surgical, ectopic eruption cases, and both males and females.
Many orthodontists anecdotally claim that their cases ―unravel‖ faster with the
use of self-ligating brackets compared to when they use conventional brackets. Their
55

claims are not supported by evidence, as most studies have demonstrated that there is no
significant difference in alignment efficiency (alleviation of crowding) with neither type
of self-ligating brackets, active and passive, compared with conventional brackets. One
study did show that with moderate crowding a passive self-ligating bracket was faster at
alignment than conventional brackets (Pandis et al., 2007). This lack of difference in
alignment efficiency between self-ligating brackets and conventional brackets may
explain the reason there was no significant difference found in overall treatment time
between the two groups. Furthermore, it has been found in previous studies in vitro
studies that self-ligating brackets have lower torque expression than conventional
stainless steel or ceramic brackets (Morina et al., 2008, Archambault et al., 2010), active
self-ligating brackets expressing torque sooner than passive self-ligating brackets
(Badawi et al., 2008). However, in a prospective in vivo study by Pandis et al. (2006),
the investigators found that self-ligating brackets clinically are equally effective at
expressing torque than conventional brackets, as measured on cephalometric headfilms.
Thus, as reported in previous studies, the lack of significance in alignment efficiency and
torque expression between self-ligating brackets and conventional brackets results in an
absence of a difference in overall treatment time between the two groups.

2. Number of Appointments
Table 3 summarizes the other main topic of this study, a comparison of the
number of appointments (office visits, excluding appointments for placement of
separators, including emergency appointments) required to complete orthodontic
56

treatment between patients treated with In-Ovation
®
R pre-adjusted self-ligating brackets
and those treated with conventionally ligated pre-adjusted adjusted brackets. Figure 20
displays a depiction of the means of the results, showing a significant reduction in the
mean number of appointments for cases treated with In-Ovation
®
R brackets compared to
those treated with conventional brackets. The mean number of appointments for the In-
Ovation
®
R group was 17.52 while the mean number of appiontments for the
conventional group was 26.48. On average, the In-Ovation
®
R cases were completed
with approximately nine fewer appointments than the conventional cases. Independent
sample t-tests confirmed the significance of this difference (p<0.001). The results of this
study is not in agreement with that of Hamilton et al.‘s study comparing treatment time
and number of appointments between cases treated with active self-ligating brackets and
those treated with conventional brackets. Hamilton et al. retrospectively selected
consecutively treated patients for both groups in the study, excluding only surgical-
orthodontic patients from both groups. Hamilton et al. included a number of patients in
both groups that had an initial phase of treatment with fixed functional appliances or
fixed class II correctors, such as pendulum-type appliances. After use of these appliances
during the initial phase of treatment, a period of ―settling‖ was followed by placement of
fixed appliances. Thus, Hamilton et al. did not use inclusion or exclusion criteria, nor did
they match the cases of the two groups examined. The types of malocclusion cases
between the two groups in Hamilton et al.‘s study may have varied signficantly, allowing
for multiple variables to have contributed to the lack of significant difference in the
number of appointments between the two groups. Skidmore et al. (2006) stated that
57

patient characterics and clinical decisions influence orthodontic treatment time. Patient
cooperation is one of these variables that affect treatment time. This factor was not
direclty assessed in this study. However, the number of broken brackets, missed
appointments, and emergency appointments were not significantly different between the
two groups. These measured factors may be influenced by patient compliance.
The results of this current study are in agreement with those reported by
Harradine (2001), Eberting (2001), and Yorita (2007). However, these studies examined
passive self-ligating brackets, not active self-ligating brackets, like that of this current
study. Furthermore, Harradine reported a more modest reduction of only four office
visits with the passive self-ligating cases. Eberting et al. reported an average reduction of
seven fewer office visits for the cases treated with passive self-ligating brackets.
With fewer appointments to complete treatment, the orthodontist can see more
patients in a given period of time because patients do not have to visit the office as
frequently. However, as they see patients less frequently, they have less control in
monitoring the patients‘ compliance and hygiene. Fewer appointments frees up time for
staff to accomplish other in-office tasks. Patients need to make less visits to the
orthodontic office and will go for longer intervals without seeing the orthodontist.
Patients need to be aware that if something breaks they should go into the office sooner
than their scheduled visit, or else treatment time is wasted. There are some patients that
may feel that if they are not visiting the orthodontist frequently progress on their
treatment is limited. Other patients would be pleased at not having to visit the
orthodontist as frequently, allowing for more time to do other things.
58

3. Number of Emergency Appointments, Broken Brackets, and Missed
Appointments
Between the In-Ovation
®
R bracket group and the conventional bracket group in
this study, there was no significant difference in the number of emergency
appointments(p=0.08), broken brackets (p=0.09), or missed appointments (p=0.06), so
these factors were not variables affecting the overall treatment time and the total number
of appointments between the two groups. Number of broken brackets can be an
indication of the types of foods the patients are eating and whether they are following
instructions on what they should avoid eating. The number of emergency appointments
can be indirectly connected to how careful the patients are with their braces, which can
also include the types of foods they are eating. Missed appointments can be an indication
of the level of the patients‘ cooperation. Skidmore et al. (2006) found that treatment time
is prolonged when patient cooperation is poor.

Treatment Mechanics
In this study‘s sample, the In-Ovation
®
R cases required significantly fewer
appointments than the conventional cases while total treatment time between the two
groups did not differ. This would result from distributing the appointments further apart
from each other, lengthening the time interval between successive appointments, as was
the case in the sample of this study (In-Ovation
®
R cases were seen approximately every
6-10 weeks and the conventional cases were seen approximately every 4-6 weeks).
59

Therefore, it appears as though In-Ovation
®
R brackets provide some mechanical
advantage over conventional brackets. The majority of the existing studies on alignment
efficiency have shown that self-ligating brackets are no more effective in reducing
irregularity than conventional twin brackets (Fansa et al, 2009, Miles, 2005, Pandis et al,
2010, Scott et al., 2008, Miles et al., 2006, Fleming et al., 2009). Some studies have
shown self-ligating brackets to be more efficient in moderate crowding (Pandis et al.,
2007) However, in the initial leveling and alignment phase of treatment, while the
archwires used are smaller in size, patients treated with self-ligating brackets can be seen
at longer intervals than patients treated with conventional brackets. The patients in
conventional brackets may have needed to be seen to change the elastomeric or steel
ligature ties.

Limitations
There were several limitations to this study:
1. The study is retrospective.
2. The difficulty in controlling all variables that could affect treatment duration,
including but not limited to biology of tooth movement, patient cooperation,
treatment mechanics, and any other factor that might have an effect on treatment
time.
3. The sample was obtained from one private practice and is representative of only
the situation in that one practice.
60

4. Quality of treatment outcome was not measured. ABO or PAR indices were not
used to compare the quality of treatment outcome. The fact that all cases were
treated by the same practitioner, it was assumed that they were treated to similar
outcomes.
5. Having practiced for 37 years the treatment philosophy of the treating
orthodontist may have change significantly over this time period.

Implications of findings on clinical practice
In the past decade, the use of self-ligating brackets has been on the rise (Keim,
2008). After reviewing the literature on self-ligating brackets the advantages of self-
ligating brackets are debatable. The primary focus of this study was to further investigate
the difference in treatment time and number of appointments required to complete
orthodontic treatment with In-Ovation
®
R self-ligating brackets compared to
conventionally ligated brackets.
The main findings of this study were the following:
1. Treatment time with In-Ovation
®
R brackets did not significantly differ from
treatment time with conventional brackets.
2. Treatment with In-Ovation
®
R brackets required significantly fewer appointments
than treatment with conventional brackets.
The results of a reduced amount of appointments required to complete treatment
has potential to impact clinical practice in orthodontics. If this finding is representative
of other clinical settings then it can be assumed that treating patients with the active self-
61

ligating bracket In-Ovation
®
R is signficantly more efficient than treating patients with
conventionally ligated brackets. Since there is no significant difference in the overall
treatment time between self-ligating cases and conventional cases, and there is a
signficant difference in the number of appointments to complete treatment, the
implications of this are that the interval time between appointments is longer for self-
ligating cases. In this study, the calculated average interval time is 6.3 weeks for the self-
ligating bracket group and 4.0 weeks for the conventional bracket group (calculated from
the avererage overall treatment time and the average number of appointments). A
redution in the amount of appointments required to finish a case is a benefit to
orthodontists. Orthodontists can see more patients and their staff will be more available
for other tasks in the office. Furthermore, patients may be more pleased that they do not
have to come in to the office as frequently. However, the orthodontist should be aware
that if patients are not visiting the office as much, they are not reminded as often about
maintaining their oral hygiene and following instructions on the care of their braces.
Other advantages of self-ligating brackets, as demonstrated in previous studies,
are that they reduce the amount of chairtime, which can increase the orthodontists
productivity. A decreased amount of chairtime also increased the availability of the
assistants for other procedures in the office.
The findings of this study refute claims from orthodontic appliance manufacturers
that treatment in self-ligating brackets shortens treatment time. Companies should not
market their products to have certain advantages if studies do not support their claims.

62

Future Research
In vitro studies have shown reduced levels of fricitonal forces with the use of self-
ligating brackets compared to conventionally ligated brackets. These frictional
advantagages results in the clinical advantage of a reduction in the number of
appointments required to complete treatment. However, additional research is required to
address the limitations of this study. Future studies may consider the following:
1. Prospective study design
2. Initial and final ABO and/or PAR scores to evaluate and compare treatment
outcomes between the self-ligating bracket group and the conventional bracket
group
3. Collect quantifiable pre-treatment criteria for matching cases between the two
groups

63

Chapter Seven: Conclusion
The objective of this study was to compare overall treatment time and number of
appointments in cases treated with In-Ovation
®
R self-ligating brackets and cases treated
with conventionally ligated brackets. Data was collected from a private practice in
southern California according to specific inclusion and exclusion criteria to limit the
number of variables that could influence treatment time and number of appointments.
The data were analyzed and the following conclusions were drawn:
1. Overall treatment time with In-Ovation
®
R brackets was not significantly different
than treatment time with conventional brackets.
2. Treatment with In-Ovation
®
R brackets required fewer appointments than
treatment with conventional brackets, an average of approximately nine fewer
appointments.

64

Bibliography

Archambault A, Lacoursiere R, Badawi H, Major PW, Carey J, Flores-Mir C. Torque
expression in stainless steel orthodontic brackets. A systematic review. Angle
Orthodontist 2010; 80(1):201-10.

Ash LJ, Nikolai RJ. Relaxation of orthodontic elastomeric chains and modules in
vitro and in vivo. Journal of Dental Research 1978; 57(5-6)685-90.

Badawi HM, Toogood TW, Carey JP, Major PW. Torque expression of self-ligating
brackets. American Journal of Orthodontics and Dentofacial Orthopedics 2008;
133(5):721-8.

Bednar JR, Gruendeman GW, Sandrik JL. A comparative study of frictional forces
between orthodontic brackets and arch wires. American Journal of Orthodontics and
Dentofacial Orthopedics 1991;100(6):513-22.

Berger JL, Byloff FK. The clinical efficiency of self-ligating brackets. Journal of
Clinical Orthodontics 2001;35(5):304-08.

Berger JL. Self-ligation in the year 2000. Journal of Clinical Orthodontics
2000;35(2):74-81.

Berger JL. The SPEED appliance: A 14-year update on this unique self-ligating
orthodontic mechanism. American Journal of Orthodontics and Dentofacial
Orthopedics 1994;105:217-23.

Berger JL. The influence of the SPEED bracket‘s self-ligating design on force levels
in tooth movement: A comparative in vitro study. American Journal of Orthodontics
and Dentofacial Orthopedics 1990;97(3):219-28.

Budd S, Daskalogiannakis J, Tompson BD. A study of the frictional characteristics of
four commercially available self-ligating bracket systems. European Journal of
Orthodontics 2008; 30(6):645-53.

Cacciafesta V, Sfondiri MF, Ricciardi A, Scribante A, Klersy C, Auricchio F.
Evaluation of friction of stainless steel esthetic self-ligating brackets in various
bracket-archwire combinations. American Journal of Orthodontics and Dentofacial
Orthopedics 2003;124:395-402.

Dewel BF. The Ribbon Arch. Angle Orthodontist 1981; 51(4):263-68.

65

Eberting JJ, Straja SR, Tuncay OC. Treatment time, outcome, and patient satisfaction
comparisons of Damon and conventional brackets. Clinical Orthodontics and
Research 2001;4:228-34.

Fansa M, Keilig L, Reimann S, Jäger A, Bourauel C. The leveling effectiveness of
self-ligating and conventional brackets for complex tooth malalignments. Journal of
Orofacial Orthopedics 2009;70(4):285-96.

Fleming PS, DiBiase AT, Sarri G, Lee RT. Efficiency of mandibular arch alignment
with 2 preadjusted edgewise appliances. American Journal of Orthodontics and
Dentofacial Orthopedics 2009;135(5):597-602.

Fleming PS, Dibiase AT, Sarri G, Lee RT. Pain experience during initial alignment
with a self-ligating and a conventional fixed orthodontic appliance system. A
randomized controlled clinical trial. Angle Orthodontist 2009;79(1):46-50.

Fleming PS, Johal A. Self-ligating brackets in orthodontics. Angle Orthodontist
2010;80(3):575-84.

Greenlee GM, ChenSS, Smith CL, Kim JE, Huang G. IADR abstract 2010.

Hamilton R, Goonewardene MS, Murray K. Comparison of active self-ligating
brackets and conventional pre-adjusted brackets. Australian Orthodontic Journal
2008;24(2):102-109.

Hain M, Dhopaktar A, Rock P. The effect of ligation method on friction in sliding
mechanics. American Journal of Orthodontics and Dentofacial Orthopedics
2003;123:416-22.

Harradine NWT. Self-ligating brackets: Where are we now? Journal of Orthodontics
2003;30:262-73.

Harradine NWT. Self-ligating brackets and treatment efficiency. Clinical
Orthodontics and Research 2001;4:220-27.

Kapur R, Sinha PK, Nanda RS. Frictional resistance in orthodontic brackets with
repeated use. American Journal of Orthodontics and Dentofacial Orthopedics
1999;116:400-404.

Kapur R, SInha PK, Nanda RS. Frictional resistance of the Damon SL bracket.
Journal of Clinical Orthodontics 1998;32:485-89.

66

Keim RG, Gottlieb EL, Nelson AH, Vogels DS 3
rd
. 2002 JCO study of orthodontic
diagnosis and treatment. Journal of Clinical Orthodontics 2002;36(10):553-68.

Keim RG, Gottlieb EL, Nelson AH, Vogels DS 3
rd
. 2008 JCO study of orthodontic
diagnosis and treatment. Journal of Clinical Orthodontics 2008;42(11)625-40.

Khambay B, Millett D, McHugh S. Evaluation of methods of archwire ligation on
frictional resistance. European Journal of Orthodontics 2004;26:327-32.

Kusy R.Orthodontic Biomaterials: From the Past to the Present. Angle Orthodontist
2002; 72(6): 501-12.

Kusy RP, Whitley JQ Friction between different wire-bracket configurations and
materials. Seminars in Orthodontics 1997;3(3):166-77.

Kusy RP, Whitley JQ. Influence of archwire and bracket dimensions on sliding
mechanics: derivations and determinations of the critical contact angles for binding.
European Journal of Orthodontics 1999;21:199-208.

Krishnan M, Kalathil S, Abraham KM.Comparative evaluation of frictional forces in
active and passive self-ligating brackets with various archwire alloys. American
Journal of Orthodontics and Dentofacial Orthopedics 2009; 136(5):675-82.

Maijer R, Smith DC. Time saving with self-ligating brackets. Journal of Clinical
Orthodontics 1990;24:29-31.

Miles PG, Weyant RJ, Rustveld L. A clinical trial of Damon 2 vs conventional twin
brackets during initial alignment. Angle Orthodontist 2006;76(3):480-5.

Miles PG. SmartClip versus conventional twin brackets for initial alignment: is there
a difference? Australian Orthodontic Journal 2005;21(2):123-7.

Morina E, Eliades T, Pandis N, Jäger A, Bourauel C. Torque expression of self-
ligating brackets compared with conventional metallic, ceramic, and plastic brackets.
European Journal of Orthodontics 2008;30(3):233-8.

Paduano S, Cioffi I, Iodice G, Rapuano A, Silva R. Time efficiency of self-ligating vs
conventional brackets in orthodontics: effect of appliances and ligating systems.
Progress in Orthodontics 2008;9(2):74-80.

Pandis N, Polychronopoulou A, Eliades T. Active or passive self-ligating brackets?
A randomized controlled trial of comparative efficiency in resolving maxillary
anterior crowding in adolescents. American Journal of Orthodontics and Dentofacial
Orthopedics 2010;137(1):12.e1-6; discussion 12-3.
67

Pandis N, Papaioannou W, Kontou E, Nakou M, Makou M, Eliades T. Salivary
Streptococcus mutans levels in patients with conventional and self-ligating brackets.
European Journal of Orthodontics 2010;32(1):94-9.

Pandis N, Vlachopoulos K, Polychronopoulou A, Madianos P, Eliades T. Periodontal
condition of the mandibular anterior dentition in patients with conventional and self-
ligating brackets. Orthodontics &Craniofacial Research 2008;11(4):211-5.

Pandis N, Bourauel C, Eliades T. Changes in the stiffness of the ligating mechanism
in retrieved active self-ligating brackets. American Journal of Orthodontics and
Dentofacial Orthopedics 2007;132(6):834-7.

Pandis N, Polychronopoulou A, Eliades T. Self-ligating vs conventional brackets in
the treatment of mandibular crowding: a prospective clinical trial of treatment
duration and dental effects. American Journal of Orthodontics and Dentofacial
Orthopedics 2007;132(2):208-15.

Pandis N, Strigou S, Eliades T. Maxillary incisor torque with conventional and self-
ligating brackets: a prospective clinical trial. Orthodontic & Craniofacial Research
2006;9(4):193-8.

Pellegrini P, Sauerwein R, Finlayson T, McLeod J, Covell DA Jr, Maier T, Machida
CA. Plaque retention by self-ligating vs elastomeric orthodontic brackets: quantitative
comparison of oral bacteria and detection with adenosine triphosphate-driven
bioluminescence. American Journal of Orthodontics and Dentofacial Orthopedics
2009 Apr;135(4):426.e1-9; discussion 426-7.

Petersen A, Rosenstein S, Kim KB, Israel H. Force decay of elastomeric ligatures:
influence on unloading force compared to self-ligation. Angle Orthodontist
2009;79(5):934-88.

Pizzoni L, Ravnholt G, Melsen B. Frictional Forces Related to Self-Ligating
Brackets. European Journal of Orthodontics Jun 1998;20(3):283-91.

Polat O, Gokcelik A, Arman A, Arhun N. A comparison of white spot lesion
formation between a self-ligating bracket and a conventional preadjusted straight wire
bracket. World Journal of Orthodontics 2008;9(2):e46-50.

Pringle AM, Petrie A, Cunningham SJ, McKnight M. Prospective randomized clinical
trial to compare pain levels associated with 2 orthodontic fixed bracket systems.
American Journal of Orthodontics and Dentofacial Orthopedics 2009;136(2):160-7.

Proffit WR. Contemporary Orthodontics, 3
rd
edition, Mosby 2000.
68

Read-Ward GE, Jones SP, Davies EH. A comparison of self-ligating and
conventional orthodontic bracket systems. British Journal of Orthodontics
1997;24:309-17.

Redlich M, Mayer Y, Harari D, Lewinstein I. In vitro study of frictional forces
during sliding mechanics of "reduced-friction" brackets. American Journal of
Orthodontics and Dentofacial Orthopedics 2003;124(1):69-73.

Reicheneder CA, Gedrange T, Berrisch S, Proff P, Baumert U, Faltermeier A,
Muessig D. Conventionally ligated versus self-ligating metal brackets--a comparative
study. European Journal of Orthodontics 2008 30(6):654-60.

Ridley J, Garret S, Moon P. Frictional forces of ligated plastic and metal edgewise
brackets. Journal of Dental Research 1979;(58):98 (abstract)

Rinchuse DJ, Miles PG. Self-ligating brackets: present and future. American Journal
of Orthodontics and Dentofacial Orthopedics 2007;132(2):216-22.

Scott P, Sherriff M, Dibiase AT, Cobourne MT. Perception of discomfort during
initial orthodontic tooth alignment using a self-ligating or conventional bracket
system: a randomized clinical trial. European Journal of Orthodontics
2008;30(3):227-32.

Scott P, DiBiase AT, Sherriff M, Cobourne MT. Alignment efficiency of Damon3
self-ligating and conventional orthodontic bracket systems: a randomized clinical
trial. American Journal of Orthodontics and Dentofacial Orthopedics
2008;134(4):470.e1-8.

Shivapuja PK, Berger J. A comparative study of conventional and self-ligation
bracket systems. American Journal of Orthodontics and Dentofacial Orthopedics
1994;106:472-80.

Sims AP, Waters NE, Birnie DJ, Pethybridge RJ. A comparison of the forces
required to produce tooth movement in vitro using two self-ligating brackets and a
pre-adjusted bracket employing two types of ligation. European Journal of
Orthodontics 1993; 15(5):377-85.

Skidmore KJ, Brook KJ, Thomson WM, harding WJ. Factors influencing treatment
time in orthodontic patients. American Journal of Orthodontics and Dentofacial
Orthopedics 2006;129:230-8.

Steiner CC. Is There One Best Orthodontic Appliance? Angle Orthodontist 1933;
3(4): 277-298
69

Stolzenberg J. The Russell attachment and its improved advantages. International
Journal of Orthodontia and Dentistry in Children 1935;9:837-40.

Stolzenberg J. The efficiency of the Russell attachment. American Journal of
Orthodontics and Oral Surgery 1946; 32:572–582.

Taylor NG, Ison K. Frictional resistance between orthodontic brackets and archwires
in the buccal segments. Angle Orthodontist 1996;66(3):215-22.

Thomas S, Birnie DJ, Sheriff M. A comparative in vitro study of the frictional
characteristics of two types of self-ligating brackets and two types of preadjusted
edgewise brackets with elastomeric ligatures. European Journal of Orthodontics
1998;20:589-96.

Thorstenson GA, Kusy RP. Resistance to sliding self-ligating brackets versus
conventional stainless steel twin brackets with second-order angulation in the dry and
wet (saliva) states. American Journal of Orthodontics and Dentofacial Orthopedics
2001;120:361-70.

Thorstenson GA, Kusy RP. Comparison of Resistance to sliding between different
self-ligating brackets with second-order angulation in the dry and saliva states.
American Journal of Orthodontics and Dentofacial Orthopedics 2002;121:472-82.

Tecco S, Festa F, Caputi S, Traini T, Di Iorio D, D'Attilio M. An in vitro
investigation of the influence of self-ligating brackets, low friction ligatures, and
archwire on frictional resistance. European Journal of Orthodontics 2007;
29(4):390-7.

Tecco S, Festa F, Caputi S, Traini T, Di Iorio D, D'Attilio M. Friction of
conventional and self-ligating brackets using a 10 bracket model. Angle Orthodontist
2005; 75(6):1041-5.

Türkkahraman H, Sayin MO, Bozkurt FY, Yetkin Z, Kaya S, Onal S. Archwire
ligation techniques, microbial colonization, and periodontal status in orthodontically
treated patients. Angle Orthodontist 2005;75(2):231-6.

Turnbull NR, Birnie DJ. Treatment efficiency of conventional vs self-ligating
brackets: effects of archwire size and material. American Journal of Orthodontics and
Dentofacial Orthopedics 2007;131(3):395-9.

70

Wahl N. Who Was Who in Orthodontics with a Selected Bibliography of
Orthodontics History. 1
st
Books Library2002.

Wahl N. Orthodontics in 3 millennia. Chapter 1: Antiquity to the mid-19
th
century.
American Journal of Orthodontics and Dentofacial Orthopedics 2005;127(2):255-9.

Wahl N. Orthodontics in 3 millennia. Chapter 5: the American Board of
Orthodontics, Albert Ketcham, and early 20th-century appliances. American Journal
of Orthodontics and Dentofacial Orthopedics 2005;128(4):535-40.

Wahl N. Orthodontics in 3 millennia. Chapter 16: Late 20th-century fixed appliances.
American Journal of Orthodontics and Dentofacial Orthopedics 2008;134(6):827-30.

Wildman AJ, Hice TL, Lang HM, Lee IF, Strauch EC. Round Table-The Edgelock
Bracket. Journal of Clinical Orthodontics 1972;6(2):613-24.

Yorita R, Sameshima GT. A Comparison of Self-ligating and Conventional
Orthodontic Bracket Systems. IADR abstract 2007.

71

Appendices
I. Appendix A: Descriptive Statistics
Descriptive Statistics
Type N Min Max Mean Std Dev.
In-Ovation
®

R

Tx Time 58 11 36 25.19 3.868
# Appt 58 11 25 17.52 2.897
Age 58 11 17 12.82 1.580
Emerg
Appt
58 0 7 2.02 1.550
Broken
Bracket
58 0 7 1.78 1.623
Missed
Appt
58 0 4 0.67 0.962
Conventional
Tx Time 44 13 34 24.14 3.874
# Appt 44 17 35 26.48 4.417
Age 44 11 24 13.46 2.967
Emerg
Appt
44 0 7 1.43 1.731
Broken
Bracket
44 0 9 2.43 2.556
Missed
Appt
44 0 4 1.07 1.149
Table 9: Descriptive statistics for In-Ovation
®
R and conventionally ligated bracket
groups

72

II. Appendix B: Analyzed Data
Analyzed Data
Groups: Bracket Type In-Ovation
®
R (I) and Conventional (C))
Variables: Number of appointments
Treatment Time
Age
Number of emergency appointments
Number of broken brackets
Number of missed appointments

Group Statistics
TYPE N Mean Std.
Deviation
Std. Error
Mean
# Appts I
C
58
44
17.52
26.48
2.897
4.417
0.380
0.666
Tx Time I
C
58
44
25.19
24.14
3.868
3.874
0.508
0.584
Age I
C
58
44
12.82
13.46
1.580
2.967
0.208
0.448
# Emerg
Appts
I
C
58
44
2.02
1.43
1.550
1.731
0.204
0.261
# Broken
Brackets
I
C
58
44
1.78
2.43
1.623
2.556
0.213
0.340
# Missed
Appts
I
C
58
44
0.67
1.07
0.962
1.149
0.126
0.173
Table 10: Groups statistics for dependent variables
73

Independent Sample T-Tests
Dependent variable: Number of Appointments
Fixed factors: In-Ovation
®
R
Conventional

t-Test: Two-Sample Assuming Equal Variances

Number of Appointments
Conventional In-OvationR
Mean 26.47727273 17.51724
Variance 19.51109937 8.394434
Observations 44 58
Pooled Variance 13.17460031

Hypothesized Mean
Difference 0
df 100
t Stat 12.34755741
P(T<=t) one-tail 3.95162E-22

t Critical one-tail 1.660234327
P(T<=t) two-tail 7.90325E-22
t Critical two-tail 1.983971466
Table 11: Independent sample T-Test for number of appointments

74

Dependent variable: Treatment Time
Fixed Factors: In-Ovation
®
R
Conventional

t-Test: Two-Sample Assuming Equal Variances

Treatment Time
Conventional
In-
OvationR
Mean 24.13636364 25.18966
Variance 15.00422833 14.9634
Observations 44 58
Pooled Variance 14.98095611

Hypothesized Mean
Difference 0
df 100
t Stat -1.361191027
P(T<=t) one-tail 0.088256382

t Critical one-tail 1.660234327
P(T<=t) two-tail 0.176512764
t Critical two-tail 1.983971466
Table 12: Independent sample T-Test for treatment time

75

Dependent variable: Age
Fixed Factors: In-Ovation
®
R
Conventional

t-Test: Two-Sample Assuming Equal Variances

Age
Conventional
In-Ovation
®
R
Mean 13.46136364 12.82276
Variance 8.802891121 2.497757
Observations 44 58
Pooled Variance 5.208964768

Hypothesized Mean
Difference 0
df 100
t Stat 1.399577217

P(T<=t) one-tail 0.082367236
t Critical one-tail 1.660234327
P(T<=t) two-tail 0.164734471

t Critical two-tail 1.983971466
Table 13: Independent sample t-test for age

76

Dependent variable: Number of Emergency Appointments
Fixed factors: In-Ovation
®
R
Conventional

t-Test: Two-Sample Assuming Equal Variances

# Emergency Appointments
Conventional
In-Ovation
®

R
Mean 1.431818 2.017241
Variance 2.995243 2.403206
Observations 44 58
Pooled Variance 2.657782

Hypothesized Mean
Difference 0
df 100
t Stat -1.79618

P(T<=t) one-tail 0.037743
t Critical one-tail 1.660234
P(T<=t) two-tail 0.075485

t Critical two-tail 1.983971
Table 14: Independent sample t-test for number of emergency appointments

77

Dependent variable: Number of Broken Brackets
Fixed factors: In-Ovation
®
R
Conventional

t-Test: Two-Sample Assuming Equal Variances

# Broken Brackets
Conventional
In-
Ovation
®
R
Mean 2.431818 1.775862
Variance 5.088266 2.633091
Observations 44 58
Pooled Variance 3.688817

Hypothesized Mean
Difference 0
df 100
t Stat 1.708329

P(T<=t) one-tail 0.045339
t Critical one-tail 1.660234
P(T<=t) two-tail 0.090678

t Critical two-tail 1.983971
Table 15: Independent sample t-test for number of broken brackets

78

Dependent variable: Number of Missed Appointments
Fixed factors: In-Ovation
®
R
Conventional

t-Test: Two-Sample Assuming Equal Variances

# Missed Appointments
Conventional
In-Ovation
®

R
Mean 1.068181818 0.672414
Variance 1.320824524 0.925892
Observations 44 58
Pooled Variance 1.095713166

Hypothesized Mean
Difference 0
df 100
t Stat 1.89117846

P(T<=t) one-tail 0.030747335
t Critical one-tail 1.660234327
P(T<=t) two-tail 0.061494669

t Critical two-tail 1.983971466
Table 16: Independent sample t-test for number of missed appointments

79

III. Appendix C: Normality Distribution Graphs

Figure 27: Normality distribution for number of appointments for the conventional
cases

Figure 28: Normality distribution for treatment time for conventional cases
0
2
4
6
8
10
12
17
20
23
26
29
32
More
Frequency
Number of Appointments
Conventionally Ligated
Brackets
Frequency
0
5
10
15
20
25
Frequency
Treatment Time (months)
Conventionally Ligated
Bracket Treatment Time
Frequency
80

Figure 29: Normality distribution for number of appointments for In-Ovation® R
cases

Figure 30: Normality distribution for treatment time for In-Ovation® R cases

0
5
10
15
20
25
11
13
15
17
19
21
23
More
Frequency
Number of Appointments
In-Ovation® R
Frequency
0
5
10
15
20
25
Frequency
Treatment Time (months)
In-Ovation® R Bracket
Treatment Time
Frequency

Abstract (if available)

Abstract The use of self-ligating brackets has become widespread in orthodontics, and manufacturers claim that they are more efficient. There are two main types of self-ligating brackets -- active and passive. Most of the previous studies on self-ligating bracket efficiency have involved passive self-ligating brackets, and the few available studies involving active self-ligating brackets include multiple confounding variables. In the current retrospective study, treatment time and number of appointments were compared between an active self-ligating appliance (In-Ovation® R ®

Linked assets

University of Southern California Dissertations and Theses

Conceptually similar

PDF

Comparison of self-ligating brackets to conventionally-ligated twin edgewise brackets for root resorption

PDF

Bonding accuracy of a novel lingual customized orthodontic appliance (INBRACE™): an in-vivo study

PDF

Shear bond strength comparison of mesh, sandblasted and laser-etched orthodontic brackets

PDF

A comparison of root resorption between Invisalign treatment and contemporary orthodontic treatment

PDF

Sexual differences and early eruption timing of the permanent dentition in Mexican adolescents- a comparison with the Caucasian standards

PDF

Evaluating the treatment efficiency of Carriere Distalizer: a cephalometric and study model comparison of Class II appliances

PDF

3D assessment of virtual bracket removal for modern orthodontic retainers: a prospective clinical study

PDF

Slow maxillary expansion for the treatment of unilateral crossbite in pre-adolescents: a long-term retrospective study of the changes in arch dimension

PDF

Mandibular plane angle changes with or without premolar extraction treatment in adult orthodontics measured using 3-D cone beam technology

PDF

Root shape frequency and direction of dilaceration: a CBCT study

PDF

Cirtual 3D placement of temporary orthodontic anchorage implants

PDF

Comparison between tooth mesiodistal angulation measurements from constructed panoramic images and three-dimensional volumetric images

PDF

Three-dimensional assessment of tooth root shape and root movement after orthodontic treatment: a retrospective cone-beam computed tomography study

PDF

Effects of insertion speed and pre-drilling on the mechanical properties of orthodontic mini-implants: in vitro mechanical study

PDF

Prevalence of arch form types and tooth size discrepancy in a Vietnamese population

PDF

Proper mesio-distal angulation and bucco-lingual inclination of the whole tooth in three-dimensional space -- a standard for orthodontic patients

PDF

The utility of bleeding on probing and 0.25% sodium hypochlorite rinse in the treatment of periodontal disease

PDF

Study of antibacterial activity and bonding properties of a multimode adhesive containing tt-farnesol

PDF

Amelogenin-ameloblastin protein interaction and function in dental enamel formation

Asset Metadata

Creator Kai, Lisa Miyuki (author)

Core Title A comparison of treatment time and number of appointments in active self-ligating brackets and conventionally ligated twin edgewise brackets

School School of Dentistry

Degree Master of Science

Degree Program Craniofacial Biology

Publication Date 04/12/2010

Defense Date 03/18/2010

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag active self-ligating brackets,conventional brackets,efficiency,number of appointments,OAI-PMH Harvest,self-ligating brackets,treatment time

Language English

Contributor Electronically uploaded by the author (provenance)

Advisor Sameshima, Glenn T. (committee chair), Moon, Holly (committee member), Paine, Michael (committee member)

Creator Email lisakai@gmail.com,lmkai@hotmail.com

Permanent Link (DOI) https://doi.org/10.25549/usctheses-m2907

Unique identifier UC1459809

Identifier etd-Kai-3605 (filename),usctheses-m40 (legacy collection record id),usctheses-c127-318952 (legacy record id),usctheses-m2907 (legacy record id)

Legacy Identifier etd-Kai-3605.pdf

Dmrecord 318952

Document Type Thesis

Rights Kai, Lisa Miyuki

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Repository Name Libraries, University of Southern California

Repository Location Los Angeles, California

Repository Email cisadmin@lib.usc.edu