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The effect of cone beam computed tomography (CBCT) imaging on orthodontic diagnosis and treatment planning

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The effect of cone beam computed tomography (CBCT) imaging on orthodontic diagnosis and treatment planning

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THE EFFECT OF CONE BEAM COMPUTED TOMOGRAPHY (CBCT) IMAGING
ON ORTHODONTIC DIAGNOSIS AND TREATMENT PLANNING
by

Soraya Chinea

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 2011

Copyright 2011 Soraya Chinea
ii
Acknowledgements
A special thank you to:
Dr. James Mah
Dr. Reyes Enciso
And to those examiners who graciously gave up time away from their practices, families,
and loved ones to spend time on this project:
Dr. Jang Anh
Dr. Dan Banh
Dr. Milton Chan
Dr. Richard Mays
Dr. Holly Moon
Dr. Rex Peters

iii
Table of Contents
Acknowledgements ii
List of Tables v
List of Figures vi
Abstract vii
Chapter 1-Introduction 1

Chapter 2- Background 3
Conventional imaging: panoramic radiography 3
Conventional imaging: lateral cephalometric radiography 6
General: CBCT imaging 9
Impacted and supernumerary teeth 12
Root resorption 16
Boundaries of orthodontic tooth movement 19
Miniscrews 22
Dental development 22
Digital models 23
Cephalometrics 23
Surgery 24
TMJ and other pathologies 25
Radiation dosimetry 26
Diagnosis and treatment planning 28
Current issues 29

Chapter 3-Hypothesis 31
Chapter 4- Materials and Methods 32
Examiner selection 34
Patient selection 35
Orthodontic records 35
Case scoring 36
Statistical analysis 37

Chapter 5- Results 39
Overall inter-rater comparison (4 examiners) 44
Inter-rater comparison based on 3-D experience 44
Non parametric correlations between experience and diagnosis
and treatment planning 44
iv

Chapter 6- Discussion 46
Differences in diagnosis and treatment planning using conventional
Records 46
Differences in diagnosis and treatment planning at all timepoints 48
The effect of experience on diagnosis and treatment planning 51
Professional guidelines 53

Chapter 7- Limitations 55
Examiner Limitations 55
Patient Records 56

Chapter 8- Conclusion 57
Bibliography 58

v
List of Tables
Table 1: Comparison of diagnostic uses for different radiographs 10
Table 2: Detection of root resorption 17
Table 3: Case scoring 38
Table 4: Frequency for differences in diagnosis 39
Table 5: Frequency for differences in treatment planning 40
Table 6: Diagnosis and treatment planning differences: score = 3 40

Table 7: Differences in diagnosis and treatment planning based on
examiner experience 44

Table 8: Correlations between experience and diagnosis and
treatment planning 45

vi
List of Figures
Figure 1: CBCT comparison to medical CT 11
Figure 2: CBCT imaging for the diagnosis of impacted maxillary canines 18
Figure 3: CBCT use in determining the boundaries of orthodontic tooth
movements 20

Figure 4: CBCT use in determining root position and resorption 21
Figure 5: Radiation exposure 27
Figure 6: Diagnosis and treatment planning questionnaire 33
Figure 7: CBCT checklist 34
Figure 8: Examiner demographic questionnaire 34
Figure 9: Frequency of scoring differences in diagnosis T1_T2 41
Figure 10: Frequency of scoring differences in diagnosis T1_CBCT 41
Figure 11: Frequency of scoring differences in diagnosis T2_CBCT 42
Figure 12: Frequency of scoring differences in treatment planning
T1_T2 42

Figure 13: Frequency of scoring differences in treatment planning
T1_CBCT 43

Figure 14: Frequency of scoring differences in treatment planning
T2_CBCT 43

vii
Abstract
Introduction: The effect of cone-beam computed tomography (CBCT) imaging on
orthodontic diagnosis and treatment planning has not been fully elucidated despite the
increasing use of 3-dimensional (3-D) radiography in dentistry. The application of
CBCT imaging in orthodontics has been shown to provide information that aids in the
localization of impacted canines
1, 2, 3
, placement of miniscrews
4, 5, 6
, identification of
pathology
7, 8
, and assists in the assessment of alveolar bone levels
9, 10
, orthodontic tooth
movements
11, 12
, the temporomandibular joint (TMJ)
12, 13, 14
, sinuses
15, 16
, and airway.
15, 17, 18

In addition, CBCT is useful for the evaluation of root resorption
11
and planning of
orthodontic treatment
19, 20
. While the clinical value of CBCT is mostly empirical, there
are no specific studies so far to evaluate the differences between the diagnosis and
treatment plans of orthodontic patients when using conventional records and CBCT
images.
Purpose: Our hypothesis is that CBCT imaging provides additional information that will
influence orthodontic diagnosis and treatment planning.
Methods: Four orthodontic examiners diagnosed and created treatment plans for 38
consecutively selected orthodontic patients using conventional orthodontic records
(photos, panoramic and lateral cephalometric radiographs) and CBCT images.
Examiners completed written questionnaires to indicate their diagnosis and preferred plan
of treatment for each case at three different points in time, each one month apart using
conventional orthodontic records for the first two analyses (T1, T2) and CBCT data in
addition to traditional records for the third (T3). The level of experience with CBCT
viii
imaging of the examiners was also scored. The diagnoses and treatment plans at the three
points in time were compared.
Results: Statistically significant differences (p<.05) were found using conventional
records and CBCT data when comparing T1 and T2 to T3 for all examiners. No
significant differences (p<.05) were present among the 4 raters when comparing the
diagnoses (p=.629) or treatment plans (p=.137) made using conventional radiographs at
T1 and T2. Examiners with greater CBCT experience showed a higher correlation and
statistically significant changes in diagnosis upon addition of the CBCT data when
compared to the less experienced examiners.
Conclusion: CBCT imaging in orthodontics results in significant changes in diagnosis but
not the treatment planning. A sufficient level of training in CBCT is necessary to take
advantage of the differences in diagnosis using 2-D and 3-D imaging. When compared to
conventional 2-D imaging, CBCT provides additional diagnostic information to the
orthodontist, however the impact that these diagnostic changes have on treatment
planning needs to be further analyzed. Future studies with greater number of cases and
examiners are needed to adequately evaluate the role of CBCT in routine orthodontic
care.

1
Chapter 1: Introduction
Diagnosis and treatment planning of orthodontic cases is one of the first steps in
the goal of achieving an excellent orthodontic outcome. Although the pursuit of ideal
occlusion, function, and esthetics drive orthodontic treatment, the path by which this is
achieved often varies widely among individual clinicians. The goal of diagnosis and
treatment planning is to outline a course of treatment based on the patient’s goals, and the
status of the patient’s dentition and surrounding craniofacial complex, while taking into
consideration biologic limitations and compliance.
Since the orthodontic specialty was introduced into the dental profession by
Edward H. Angle in 1900, nearly all aspects of orthodontic care, from diagnostic tools to
retention protocols, have been disputed. Each orthodontist relies on their artistic vision,
esthetic ideals, scientific knowledge, education, and clinical experience to guide their
practice. Innumerable diverse philosophies exist that seek to provide easier, more ideal,
and/or faster results than others. Despite huge advances in orthodontic treatment over the
years, several of these issues seem to have a cyclic presence in orthodontic care. For
example, through the decades the pendulum continues to shift back and forth between
those in favor and less favorable to extraction treatment. Retention protocols differ
greatly among providers. Various ideas exist on the utility and method of action of
functional appliances. These debates reflect the multi-factorial nature of orthodontics, in
diagnosis and treatment planning, and many other areas within the field.
Orthodontic records and the clinical exam serve as integral components in
planning orthodontic treatment. For decades, orthodontic records have consisted of
2
photos, study models, and panoramic and lateral cephalometric radiographs. Recently,
new imaging modalities have been introduced to the dental field, which impart new
information to the clinician. These technologies have changed many aspects of how
dentistry is practiced today.
Since the introduction of CBCT into the dental field at Loma Linda University in
2001, cone beam computed tomography (CBCT), or digital volume tomography (DVT),
has become an increasingly important source of 3-dimensional (3-D) data in dentistry.
21

Given that CBCT imaging is still relatively new to the dental field, continued exploration
of all of the capabilities of this method of 3-D imaging is needed. The inevitable
evolution of the practice of dentistry and orthodontics requires that the field take
responsibility for the implementation of new technology, such as CBCT, by fully
investigating the potential risks and benefits to the patient.
3
Chapter 2: Background
For decades, orthodontists have used study casts, intra- and extra-oral photographs,
a clinical examination, and panoramic and lateral cephalometric radiographs to guide
diagnosis, plan a course of treatment, monitor treatment progress, and evaluate case
outcomes. The radiographic components of orthodontic treatment serve many purposes.
Currently, routine dental treatments rely almost entirely on 2-dimensional (2-D)
radiographs, although recently the introduction of CBCT has forced the dental field to
consider novel diagnostic techniques that challenge the use of 2-D imaging.
Within various areas of dentistry, the replacement of many 2-D radiographs with
those available in 3-dimensional (3-D) is a growing trend.
12
Orthodontic imaging is
performed to measure and record the form and size of anatomic structures in the
craniofacial complex. With such a goal in mind, the gold standard of imaging is to
achieve an accurate replication of the true anatomy. Although traditional orthodontic
records consist of panoramic and cephalometric images, there are inherent drawbacks in
using 2-D films to visualize 3-D structures. Conventional radiographic techniques are
commonly used in order to balance the expected benefits with cost and associated risks to
the patient, thus settling for a less than ideal radiographic representation of the anatomic
truth.
Conventional imaging: panoramic radiography
Panoramic projections provide information about development of the dentition and
allow detection of some supernumerary, impacted, and missing teeth. These images also
provide information on the sinuses, the temporomandibular joint (TMJ), and the presence
4
of pathology.
Despite the extensive use of panoramic films in orthodontics, there are several
factors negatively influencing the reliability and accuracy of these films. A panoramic
image is made by creating a region of interest that conforms to a generic jaw size and
form. Since no human jaw perfectly matches this generic jaw, the image that is obtained
fails to accurately represent the size, form, and location of structures in an actual subject.
The x-ray beams are angled in various horizontal and vertical paths, leading to a distorted
representation of the anatomy. Panoramic images have an inherent magnification of
anywhere from 10%-30%.
22
Head positioning is critical and if not performed properly,
results in overlap of structures and distortion, minimizing diagnostic quality.
23
Curvature
differences of the upper and lower jaws causes overlap of structures and distortion,
further complicating diagnosis and planning of treatment.
24, 25
Superimposition of
surrounding structures, including shadows of soft tissue and air spaces, and the
appearance of ghost images, makes correct diagnosis difficult.
26, 22

In orthodontics, panoramic films are commonly used to assess root positioning
before, during, and after treatment. Previous research indicates that assessment of
mesiodistal root angulation using panoramic radiographs is unreliable and should be
approached with caution.
23, 27, 28, 29
One study evaluated the effect of buccolingual root
angulation on the mesiodistal angulation of teeth using panoramic radiographs. The
perception of root parallelism was found to be modified in the canine-premolar areas by
changes made in the buccolingual orientation of the teeth.
30
In another investigation, a
skull was repositioned 5 times (ideal position and 5 degrees up, down, left, and right
5
compared to ideal) to study the effects of vertical and horizontal head position in
panoramic evaluation of mesiodistal root angulations. The majority of the changes in
head position produced image angles that were statistically significantly different than the
ideal head position. The maxillary teeth were more sensitive to 5 degree changes in the
up/down direction. As the head was positioned upward a mesial projection of the teeth
resulted, whereas a downward position of the head caused a distal projection of the
teeth.
29
The mandibular anterior teeth were more sensitive to variations in the horizontal
head position. The projected mesiodistal angular difference between the horizontal
repositioning to the right and left ranged from 4.0 degrees to 22.3 degrees. Interestingly,
the maxillary teeth were not greatly affected by horizontal changes in head position
whereas the mandibular teeth were relatively unaffected by vertical changes in head
position.
29

When evaluating the use of different panoramic imaging devices, previous research
found that the majority of the image angles from various devices demonstrate similar
statistically significant deviations from true angle measurements.
29
Panoramic images of
the maxillary teeth tend to project the anterior roots more mesially and posterior roots
more distally. This was evidenced in the appearance of extreme root divergence between
the maxillary canines and first premolars. The mandibular dentition projected images
with almost all of the roots more mesial than the true position, with the largest difference
in angulations shown as root convergence between the lateral incisor and canine. The
differences between perceived root angulations and true measurements appears to be
uniformly under and over estimated regardless of the differences in panoramic units.
29

6
When panoramic-like images created from CBCT data were evaluated for accuracy
of mesiodistal root positions, the angular projections using CBC-generated panoramic
images were found to be closer to the true mesiodistal angulation than conventional
panoramic radiographs.
31
Assessment of root angulations via CBCT was shown to be
very accurate when compared to plaster model measurements (the gold standard) and
panoramic radiographs.
32
Despite the shortcomings of panoramic projections and the
existence of more accurate imaging techniques, panoramic films continue to be used to
evaluate mesiodistal root positions.
Panoramic radiographs have proven to be unreliable in the diagnosis of periodontal
disease in some studies, whereas others have not shown such a negative effect.
33, 34, 35

Upon evaluating the accuracy of CBCT, periapical, and panoramic images for detection
of apical periodontitis, it was found that CBCT projections were more reliable in making
a clinical diagnosis.
36
In this study, 888 imaging exams of patients with endodontic
infections were evaluated. The prevalence of acute periodontitis was significantly higher
when diagnosis was done using CBCT images. Sensitivity for periapical and panoramic
radiographs was 0.55 and 0.28, respectively. The correct identification of acute
periodontitis with panoramic and periapical radiographs was possible when patients
showed advanced status of the disease.
36

Conventional imaging: lateral cephalometric radiography
Lateral cephalometric films provide important information on the position of the
teeth in relation to both jaws and the cranial base as well as an understanding of the
relationships of the maxilla and mandible to one another and to the craniofacial complex.
7
Via the designation of specific hard and soft tissue anatomic points, lateral cephalometric
radiographs serve as a means to study craniofacial development, growth, and orthodontic
treatment. However, there are many inherent deficits in using 2-D imaging to analyze
3-D structures, including the displacement of structures in both a vertical and horizontal
direction.
Cephalometric analyses are based on the perfect superimposition of the right and
left sides of the face, which is uncommon in clinical practice. A geometric error is also
present with the cephalometric projection. The magnification on the left and right sides
of the face vary, causing structures further away from the film to be magnified to a larger
degree than structures closer to the film.
The use of panoramic and lateral cephalometric imaging to derive clinical
information and plan treatment has been questioned.
39, 40, 41
This is due in part to many
inaccuracies of the 2-D cephalometric projection and associated analyses. For one, the
lateral cephalometric image and analysis is highly dependent upon the projection itself
and adequate identification of landmarks. Previous research indicates that there is
significant error in the identification of cephalometric landmarks due to shadows, overlap
of structures, a lack of defined anatomic features, and variations in head positioning.
42

Studies show that errors in cephalometric landmark identification are considered major
sources of cephalometric errors.
21, 43
Baumrind reported that the errors in landmark
identification were large and should not be ignored.
37
He also found that the magnitude or
error in identification varied greatly from one point to another, with bilateral structures
posing the greatest challenge. He argued that there was difficulty in precisely locating a
8
particular landmark using lateral cephalometric film.
37
Bilateral structures are
superimposed, which can present difficult in locating structures such as condylion,
gonion, and orbitale.
44
Additional factors complicating cephalometric analysis include
patient head positioning, superimposition of bilateral structures, and individual variation
in landmark identification among clinicians.
37, 38
Hixon reported that the combination of
errors present in cephalometric imaging can be significant enough to affect diagnosis and
treatment planning.
40

As an adjunct to diagnosis and planning treatment with panoramic and
cephalometric radiographs, orthodontists often utilize occlusal and periapical films.
Periapical films provide many benefits to diagnosis and treatment planning, including the
ability to assess periodontal and overall dental health, root length and shape, root
parallelism, and positions of impacted or erupting teeth. However, superimposition of
adjacent structures poses a problem when attempting to accurately identify the
buccolingual location of an impacted tooth using 2-D radiology. Some clinicians take
multiple periapical radiographs and use Clark’s method (the buccal object rule) to make a
positional diagnosis.
45
This method does not provide the same resolution and accuracy as
CBCT. The two periapical images may not be sufficient to properly identify the location
of the impacted tooth. Armstrong concluded that examiners evaluating the position of
ectopic maxillary canines were “unsure” of the diagnosis in 12% of evaluated cases using
the vertical parallax technique (VP) and 5% using the horizontal parallax technique
(HP).
46
Correct location of the ectopic canines was 83% using HP versus 68% with VP
(p<0.05). Diagnostic sensitivity for canines in the palatal position was significantly
9
greater for HP (88%) than for VP (69%). Both the VP and HP techniques were not
effective in localizing canines positioned buccally, each yielding a sensitivity of 63%.
Although the HP exhibits superior diagnostic capabilities when compared to the VP
technique, neither has been shown to provide accurate diagnosis in all cases of ectopic
canines.
46

Occlusal and periapical films are also subject to elongation, foreshortening, and
magnification, all of which lend to less accurate depictions of actual anatomic
relationships.
47, 48
The deficiencies associated with 2-D films may jeopardize the
interpretation of information and can negatively influence diagnoses.
General: CBCT imaging
In contrast to 2-D radiography, 3-D imaging provides the clinician with the ability
to view data in 360 degrees and in any plane of space. Volumetric data from CBCT can
be viewed in 2-D by reformatting the images axially, sagittally, coronally or from other
custom perspectives. In addition, superimposing structures may be digitally removed to
enhance visualization. Periapical, occlusal, panoramic, and lateral cephalometric
radiographic views can be generated from a single 3-D image.
49
These projections
provide a one-to-one measurement of distances between structures and accurate
visualization of the relationship between the tooth and adjacent structures.
49
This allows
for a direct application to force vectors in orthodontic tooth movement, facilitating the
planning of biomechanics and appliance design. Cone beam data can be altered in space
to facilitate a more reliable means of superimposition of serial cephalometric
radiographs.
50
The data can be reformatted in various planes to allow the clinician to
10
generate a lateral cephalometric image of the right or left side only, thus avoiding overlap
of bilateral structures. CBCT has numerous advantages over traditional 2-D radiographic
images (Table 1).
12

Table 1: Comparison of diagnostic uses for different radiographs
Imaging goal Periapical Panoramic Lateral
Cephalometric
CBCT
Facial soft
tissues
--- --- + ++
Tooth crowns + + + ++
Tooth roots ++ ++ --- +++
Localize
anatomy
+ + + ++++
Determine jaw
boundaries
--- ++ --- ++++
TMJ (bony
structures)
--- + --- ++++
Airway --- --- ++ ++++
Face surface
geometry
+ ++ ++ +++

CBCT imaging is a 3-D imaging technique that directs a divergent cone-shaped
beam of ionizing radiation through the middle of a particular zone of interest onto an x-
ray detector on the opposite side of the patient. The detector acquires a full volume of
--- No value
+ Low value
++ Moderate value
+++ High value
++++ Highest value

11
images in one rotation, enabling the creation of a 3-D image.
51, 52
CBCT images are
derived almost immediately and may be manipulated to prevent overlap of structures for
accurate visualization of areas of interest. Additional advantages of CBCT include good
image quality for diagnosis and geometrical accuracy.
53, 54, 55

Figure 1: CBCT comparison to medical CT

Computerized tomography (CT) was developed by Sir Godfrey Hounsfield in
1971 and rapidly revolutionized the medical field.
49
Computed tomography is one of the
most valuable imaging techniques used in the medical field today. CT scans have been
proven to be successful in representing the true 3-D morphology of the craniofacial
structures. However, due to a relatively high radiation exposure, CT imaging is not
commonly used in the dental field.
12
There are two principle factors that differentiate medical CT from CBCT, namely
the source detector and the method in which the images are acquired. Conventional CT
devices contain a high-output rotating anode generator. A fan shaped x-ray beam is
emitted from the source and the image data is recorded on detectors arranged in 360
degrees around the patient. These images capture the patient as a series of axial cuts or
“slices” and can then be stacked in a 3-D volume or viewed as individual cross sections.
12

In contrast, the cone-shaped beam emitted in CBCT is a low-energy fixed anode tube
directed at intensifiers and sensors to capture the image in one rotation around the patient.
It was not until the advent of cone beam computed tomography (CBCT) imaging
13 years ago that dentistry was greatly affected by 3-D radiology. The Food and Drug
Administration (FDA) approved the first CBCT unit for dental use in the United States in
March, 2001.
56
Since then a number of other CBCT units have been FDA approved in
the United States.
In 2009, a systematic review reported that 16% of all articles investigated for
information on CBCT scans were orthodontic articles, indicating growing interest in the
use of cone beam technology in the field.
57
Some of the most prevalent topics studied in
3-D imaging in orthodontics include the use of cone beam to evaluate the boundaries of
orthodontic tooth movement
11
, impacted teeth
1, 2, 3
, pathology
7
, miniscrew placement
4,5,6
,
treatment planning
19, 20
, and surgery
19, 58
.
Impacted and supernumerary teeth
Impacted and supernumerary teeth are common anomalies that are often aided by
the diagnostic benefits of CBCT. Supernumerary teeth can present a challenging clinical
13
scenario. Clinicians can face difficulty in identifying the supernumerary tooth from
normal teeth and precisely locating it in cases of impaction. By manipulating 3-D images,
a clinician can determine the precise location of a supernumerary tooth, more easily
distinguish it from the normal tooth, and determine the appropriate treatment route.
11
The
benefits of CBCT imaging are commonly applied to impacted teeth. Impacted teeth are
often unable to erupt into the dental arch due to lack of space, thus can present in
locations in close proximity to adjacent structures, making correct diagnosis with
traditional radiographs a difficult endeavor.
The maxillary canine is the second most commonly impacted tooth (third molars
are the most common). The prevalence of permanent maxillary canine impaction ranges
from 1-3%.
59-63
For clinicians, treatment of an impacted canine can present a very
challenging and frustrating situation, in which the patient is often scheduled for many
office visits and overall treatment time is prolonged.
64
Localization of an impacted
canine will often begin during the clinical examination. Inspection of the area may reveal
clues, including possible palpation of the tooth and the displacement of adjacent teeth.
Superimposition of adjacent structures poses a problem when attempting to accurately
identify the location of an impacted tooth using 2-D radiology. On panoramic films,
superimposition in the anterior maxilla and palate may complicate diagnosis by
concealing the tooth. Multiple periapical radiographs do not provide the same resolution
as does CBCT and does not identify the tooth position in space as accurately as a 3-D
image.
3

Conventional radiographic techniques exhibit various degrees of sensitivity in the
14
identification of impacted teeth. The accuracy of diagnosis when using panoramic images
appears to be largely dependent on the degree and location of the canine impaction. The
accuracy in diagnosis of the labio-palatal location of impacted maxillary canines was
80%-90% based on the magnification inherent to panoramic images.
65, 66
For localization
of an impacted canine using the parallax technique, the palatal sensitivity was 89% and
the buccal sensitivity was 46%.
67
Other studies have established the horizontal sensitivity
at 68% and vertical sensitivity at 83%.
46
Despite these shortcomings and the existence of
3-D imaging to revealing true anatomic positions, orthodontists have been using 2-D
imaging for canine localization for some time. Although in some clinical situations
traditional radiographs may supply ample information for an adequate diagnosis, the
radiographic detail shown in CBCT is superior. Cone beam data allows for localization of
canines in the entire maxilla and adjacent zones without the presence of superimposed
structures. CBCT data can be reformatted to enable specific localization of the tooth in
relation to anatomic structures, delineation of the long-axis orientation of an impacted
tooth, and identification of the presence, absence, and extent of root resorption on
adjacent teeth.
68, 69

There is compelling evidence that CBCT scans aid in the diagnosis and treatment of
impacted teeth.
1, 2
When compared to traditional 2-D radiology, oral surgeons utilizing 3-
D data can better plan the surgical exposure of impacted teeth by taking advantage of
accurate diagnosis to carry out a less traumatic surgical exposure.
19, 70
An accurate
diagnosis of the location of the impacted tooth is important in determining the ideal
treatment plan, exact route of surgical exposure, and the biomechanical principles that
15
will be employed to bring the tooth into the arch.
70, 19
Accurate identification of the
position of a tooth in space can decrease the total treatment time, reducing the overall
time for potentially broken appliances, decalcification, and root resorption. These studies
indicate that accurate diagnosis and planning may lead to a faster resolution of problems
in addition to a better overall prognosis. CBCT also allows for customized treatments for
each patient, taking into account specific biological considerations to implement
biomechanical approaches. This may be especially useful in the treatment of impacted
teeth.
A higher canine location has been reported with 2-D localization techniques when
compared to 3-D.
3, 46
Panoramic radiographs are directed from a slightly negative
angulation of -7 degrees. This angulation affects the accuracy of impacted canine
localization by showing palatally impacted canines at a higher location than labially
located canines.
46
The vertical position of impacted maxillary canines has been shown to
greatly impact estimated treatment outcomes, with canines located in a higher position
requiring longer and more difficult treatment.
3

In order to create a treatment plan that will satisfy a patient’s desires and provide
the most stable, functional, and esthetic outcome, accurate diagnosis is critical. A recent
study analyzing a sample of 80 children with retained and ectopically positioned
maxillary canines revealed that upon the addition of information provided from CBCT
data, treatment plans changed in 43.7% of the cases.
71
This was largely due to the
additional information used to precisely locate the buccolingual dimension of the tooth as
well as by providing information on root resorption of adjacent teeth.
71
In another
16
investigation, 27 orthodontic patients with 39 unerupted maxillary cuspids were
examined using 2-D (panoramic, periapical, lateral cephalometric) and CBCT data. Eight
dentists evaluated the position of the canine, adjacent root resorption, case difficulty,
treatment choice options, and quality of the images. Differences in the localization of the
impacted canines between the two techniques were present. Increased precision in the
localization of the canines resulted in different diagnoses and treatment plans. When
asked to make a treatment choice, agreement was found for 70.5% of the cases, resulting
in a statistically significant inconsistency of plans. Plans made using 2-D treatments
included more observational approached, whereas active intervention was the treatment
of choice using 3-D data. 3-D data yielded more expansion and space maintenance
treatments. Additionally, more root resorption was found on 3-D data.
3
These results
highlight the benefits of 3-D imaging in the treatment of impacted canines.
Root resorption
For years the inadequacies of using traditional radiographs to estimate root
resorption have been known. Over 25 years ago, a study was conducted in which intraoral
films were found to have a low sensitivity in diagnosing resorption on incisors adjacent to
ectopically erupting canines.
68
Resorption on these buccal and palatal surfaces of teeth
adjacent to an impacted tooth will not be seen in a 2-D image until there is a significant
amount of shortening of the lateral incisor root or when the resorption has caused a
change in the mesiodistal root shape. Traditional imaging can mask the presence or
absence of dental defects as well as the severity of root resorption. Clinicians using 2-D
17
images to report the status of the teeth adjacent to an unerupted or impacted tooth may be
grossly underestimating the true amount of resorption present in such cases.
In 2009, a study was conducted to evaluate the differences in detecting apical root
resorption after orthodontic treatment by comparing panoramic radiography with
CBCT.
72
In total, 275 teeth in 22 patients were analyzed as the patients approached the
end of fixed appliance orthodontic treatment. When panoramic images were examined,
17 teeth (6.2%) could not be evaluated. Statistically significant differences were found
between the two methods of evaluation (Table 2). CBCT allowed identification of 2 teeth
with severe resorption, whereas none were identified with panoramic films. These
findings suggest that apical root resorption is underestimated when evaluated on
panoramic x-rays. Accordingly, CBCT may aid in diagnosis when clinical situations
indicate that root resorption may be a concern. This may play a crucial role in creating an
ideal long-term orthodontic plan of treatment.
Table 2: Detection of root resorption
Panoramic CBCT
No resorption 56.5% 31%
Mild resorption 33.5% 49%
Moderate resorption 8% 19%

CBCT imaging can be used to accurately assess the proximity of the impacted
canines to the adjacent lateral incisors. This offers many benefits, especially in viewing
the buccolingual plane, which cannot be easily assessed using conventional techniques.
Previous research found that root resorption could be visualized approximately 50% more
accurately with CBCT images when compared to intraoral radiographs.
20
When utilizing
18
CBCT data to evaluate the extent of root resorption associated with ectopic maxillary
canines, Ericson and Kurol found that 38% of lateral incisors and 9% of central incisors
exhibited evidence of resorption.
73
In another study, root resorption of incisors associated
with impacted maxillary canines was found to be present on 66.7% of lateral incisors and
11.1% of central incisors.
1
There is a strong correlation between diagnosis of root
resorption using CBCT and that seen by direct visual observation of the roots of extracted
teeth.
74
Most clinicians grossly underestimate the amount of resorption present on teeth
adjacent to impacted canines, a finding that impacts diagnosis and treatment planning in a
profound way.
19, 20

Figure 2: CBCT imaging for the diagnosis of impacted maxillary canines

19
CBCT scans provide detailed 3-D images useful for the localization of impacted
maxillary canines and assessment of root resorption on adjacent teeth (Figure 2). A
panoramic radiograph (a) fails to provide adequate information on the exact location of
the bilaterally impacted canines. The images created by reconstructing the CBCT data to
show the occlusal, frontal, and superior views (b, c, and d, respectively) of the impacted
teeth enable the orthodontist to plan the surgical exposures and mechanics. In this case it
is critical to move the canines distally to avoid contact with the lateral incisor root, prior
to bringing the tooth into the arch. Root resorption is evident on both lateral incisors.
11
Boundaries of orthodontic tooth movement
Sectional views of the dentoalveolar complex aid orthodontists in assessing palatal
bone thickness
78, 79
, alveolar bone height
9, 10
, and the exact tooth positions and
inclination.
.80, 81, 32
CBCT provides information about the spatial boundaries of tooth
movement by detailing the limitations of alveolar bone. These can be crucial in planning
orthodontic tooth movements. Restricted movements into areas of dense bone, adjacent
teeth, diminished bone, or through cortical plates can be eliminated by pretreatment
assessment of cross-sectional data. Tip, torque, intrusion, or extrusion can be planned by
visualizing the labial or buccal boundaries denoted by the cortical margins of the alveolar
bone. For example, this would be important in determining how to treat a patient with an
excessive overbite. If there was not sufficient bone apical to the maxillary incisor roots
for intrusion of the incisors, an orthodontist would tend towards correcting the deep bite
via other orthodontic means, such as using a bite plate to allow eruption of the posterior
teeth.
20
CBCT can be used to determine the boundaries of orthodontic tooth movement
(Figure 3). A panoramic view of a bimaxillary protrusive patient does not show the
limitations of orthodontic movements in the buccal or lingual directions (a). Roots of the
maxillary teeth appear to lie within normal limits (1:2 crown to root ratio). Cross
sectional sagittal views (b, d) along the long axis of the incisors shows that the incisor
roots are short (crown to root ratio of approximately 1:1). The width of the bone housing
the anterior teeth is narrow, limiting the clinician’s ability to retract the incisors. The
patient is protrusive in profile, however the presence of short roots and the limitations of
anterior tooth movement would lead the orthodontist towards a non-extraction treatment
approach.
11

Figure 3: CBCT use in determining the boundaries of orthodontic tooth movements

21
Figure 4: CBCT use in determining root position and resorption

CBCT allows for proper diagnosis of the transposed roots of a maxillary canine
and first premolar (Figure 4). Root positioning is identified by using 2-D cross sectional
slices of the area, which reveals that the canine root is buccal to the premolar root.
Identifying tooth and root position is critical for orthodontic diagnosis and treatment
which requires that the tooth roots be moved out of one another’s path. An additional
22
benefit of CBCT is the identification of the bone around the teeth, which will indicate
which movements are ideal within the confines of the bone present.
11

Miniscrews
Miniscrews have revolutionized the treatment of some orthodontic cases by
providing a means of absolute anchorage. Keys to successful placement and use of
miniscrews include minimizing the risk of harm to adjacent structures and knowledge of
optimal bone for ideal placement, stability, and mechanical movements. In order to avoid
perforation of the maxillary sinus or adjacent tooth roots. CBCT scans can be used to
fabricate pre-surgical guides for the accurate placement of orthodontic miniscrews,
positively impacting orthodontic treatment outcomes and efficiency.
5, 6
CBCT data has
been found to be useful in determining ideal locations for the placement of miniscrews in
various maxillary and mandibular sites via 3-D assessment of alveolar bone widths and
heights.
4

Dental Development
The intricate processes of dental development can yield deviations in the number
of teeth, tooth positions, tooth shapes, and sequence of eruption. These deviations can be
lost when using conventional imaging. CBCT offers a comprehensive view of the
dentition that is free of distortion. By reformatting the 3-D data, one can visualize tooth
roots, missing, supernumerary, and anomalous teeth, and the orientation of the teeth in
the arch. This can provide valuable information on the eruption pattern and assist in
preemptively planning for future dental needs, including serial extractions and custom
appliances.
23
Digital Models
Traditional orthodontic records typically include study casts to aid in diagnosis,
evaluation of treatment progress, and the critique of case completion. Using CBCT data
(AnatoModel by Anatomage Inc., San Jose, CA), digital study models can be produced.
75

Digital study models eliminate the need to take alginate impressions, reducing the time
patients spend in the orthodontic chair and the space needed to store patient records.
There are many other benefits to using digital study models, including the ability to view
clinical crowns with the tooth roots in alveolar bone. Soft tissue can be viewed in
relation to the dentition, skeletal structures, and TMJ in order to gain a global
understanding of the craniofacial structures. Computer software can be used to register
the digital models with the hard and soft tissue images. Tissue responses to growth and
treatment can be predicted and simulated based on movements of the tissue structures
linked to the digital study models.
12
Other benefits of digital study models include the
ability to manipulate movements of individual teeth in order to predict treatment
outcomes.
Cephalometrics
Research has confirmed that cephalometric measurements carried out on CBCT-
generated cephalograms can be used to conduct analyses that are comparable to those
carried out on conventional cephalograms.
76, 77
A previous study found that multi-planer
reconstructions of CBCT images facilitate a more precise identification of traditional
cephalometric landmarks when compared to landmark identification completed using 2-D
cephalometrics.
44
Difficulty in precisely locating important bilateral structures due to
24
superimposition, including condylion, gonion, and orbitale, was alleviated by using 3-D
data.
44
This suggests that pinpointing landmarks in the mediolateral direction is most
likely related to a lack of proper landmark identification in the third dimension. Cone
beam imaging has the potential to introduce novel anatomic landmarks and analyses that
may prove to be more reproducible, precise, and easily identified for cephalometric
tracing, thereby increasing the diagnostic strength of cephalometrics.
Surgery
There is significant information that can be extracted from 3-D scans and applied
to the orthodontic and surgical treatment of patients undergoing orthognathic surgery.
CBCT images can be helpful in the assessment of skeletal age by evaluation of the
cervical vertebrae morphology, which is especially beneficial in predicting the growth of
surgical patients.
82
CBCT images permit the visualization of the upper airway anatomy
which is particularly important in planning mandibular and maxillary surgical movements
in patients with obstructive sleep apnea and limited airway patency.
17
Total airway
volume and minimum cross sectional areas can be seen and utilized in the diagnosis and
treatment of individuals suffering from obstructive sleep apnea.
18
Identification and
surgical correction of patients with skeletal asymmetries is also facilitated by CBCT
imaging.
83
Orthognathic surgeries can be simulated with both hard and soft tissue
manipulation through utilization of a recreated virtual patient using 3-D software. It is
possible to simulate the movements of a planned surgery and demonstrate the anticipated
esthetic outcome by linking the hard tissue surgical procedures to the overlying soft
25
tissue. CBCT imaging provides numerous benefits to surgeons and can be a very useful
tool in treatment planning surgical procedures.
58

TMJ and other pathologies
The role of the TMJ in achieving an optimal orthodontic treatment outcome is
especially important in cases where pathologies exist. CBCT has been shown to provide
precise imaging of the TMJ that is free of distortion and superimposition.
13
Evaluation of
the TMJ using CBCT creates images that are “of high diagnostic quality” with
additionally benefits over conventional CT scans.
14
This data suggests that CBCT may be
the optimal imaging modality used in the investigation of bony changes in the TMJ.
14
In
2007, a study was conducted in which CBCT scans were taken on 500 orthodontic
patients. Of these cases, incidental findings were noted in 25% of the sample, including
TMJ, airway, and endodontic abnormalities.
7
Unexpected pathologic findings not
initially seen using traditional radiographic evaluation may delay orthodontic treatment
until they are correctly addressed.
The presence of TMJ abnormalities and symptoms play a critical role in
orthodontic treatment planning and are important to evaluate prior to commencing
orthodontic care. A previous investigation compared CBCT to panoramic radiography
and linear tomography (TOMO) to evaluate condylar cortical erosion on 30 skulls, 19
with normal condylar morphology and 18 with erosion of the lateral pole. Intra-observer
reliability was the greatest with TOMO images although the diagnostic accuracy of
CBCT was significantly greater than all of the other imaging techniques(0.95 +/- 0.05 for
static viewing) and (0.77 +/- 0.17 for interactive viewing). The diagnostic accuracy of
26
interactive CBCT imaging was significantly greater than all other modalities (normal
panoramic [0.64 +/- 0.11], TMJ-specific panoramic [0.55 +/- 0.11], TOMO [0.58 +/-
0.15]). CBCT images have been shown to provide superior accuracy and reliability than
both TOMO and TMJ panoramic projections in the detection of condylar cortical
erosion.
84

The advantages of CBCT have been shown empirically in many areas of
dentistry. Endodontic applications of cone beam include diagnosis of endodontic
pathology, canal morphology, assessment of pathology of non-endodontic origin,
visibility of external and internal root resorption, implant planning, and pre-surgical
endodontic planning.
59
Additionally, CBCT is useful in the identification of root and
alveolar fractures, resorptive lesions, and pathology.
59, 85
CBCT also has been shown to
aid in locating the inferior alveolar canal to assist in avoiding trauma to the nerve during
mandibular third molar extractions. 3-D scans have proven to provide beneficial
information for the placement of implants and evaluation of the maxillary sinus for sinus
lift procedures.
86, 22

Radiation dosimetry
The field of view (FOV) in CBCT can range from a localized region (also called a
focused, small field, or limited field of view), single arch (5-7cm), inter-arch (7-10cm),
maxillofacial (10-15cm) or craniofacial (>15cm). In general, the smaller the scan volume,
the higher the resolution of the image. The greater the FOV, the greater the radiation
exposure to the patient.
Since CBCT is a form of computed tomography, many assume the levels of
27
radiation exposure mirror those found in medical CT scans. A major advantage of CBCT
imaging is that radiation exposure is considerably less than a medical CT.
51,,87-93
The
radiation exposure from a conventional CT is approximately 100-300 microsieverts (μSv)
for the maxilla and 200-500 μSv for the mandible.
94
The radiation exposure (for both
mandible and maxilla) from CBCT (i-CAT model) is between 34-102(μSv), depending
on the time and resolution of the scan.
95

Figure 5: Radiation exposure

Although radiation exposure varies among different CBCT units, one study
estimates that a full craniofacial scan produces a radiation exposure of 87 to 206μSv.
96, 97

28
In contrast, traditional orthodontic radiographs individually are associated with less
radiation exposure. While individually a panoramic film (14.2-24.3μSv), a full-mouth
series (13-100μSv), and lateral cephalogram (10.4μSv) expose the patient to significantly
less radiation, the combined radiation exposure would be similar or only marginally less
than CBCT when taken in combination.
96
Another report estimates that radiation
exposures for a periapical radiograph (<8.3μSv), panoramic (9-26μSv), cephalometric (3-
6μSv), full mouth series (35-388μSv), medical CT (maxilla and mandible- 2,000μSv),
CBCT (dentoalveolar or focused field of view- 5-38.3μSv) (Figure 5).
91

In society today, the increase in disease and cancer rates has lead to even greater
levels of public concern in regards to limiting lifetime radiation exposure. The risks
associated with radiation exposure must be heavily weighed against the potential
diagnostic and therapeutic yield of CBCT. As technology advances, it is expected that
CBCT machines available on the market will only continue to decrease in radiation
exposure while advancing in resolution
Diagnosis and treatment planning

Orthodontic education, diverse clinical experiences and treatment philosophies,
and the number of years in practice are all factors that may influence orthodontic
diagnosis and treatment planning. Diagnosis and treatment planning include both
subjective and objective measures, leading to variation not only between clinicians but
often among individual clinicians. Studies have shown that reliability in orthodontic
diagnosis varies widely. Some research shows high inter-examiner reliability and
agreement between information obtained for diagnostic purposes.
98
Other studies have
29
found that inter-examiner reliability for various diagnostic factors depends on the
malocclusion, ranging from poor reliability in the assessment of maxillary crowding
(K<0.40) to excellent reliability for evaluating the presence of posterior crossbite
(K=0.79).
99,100
In another investigation, calibrated examiners measured complexity,
outcome, and treatment need by evaluating pretreatment and post-treatment study casts.
Inter-rater agreement for the three parameters varied widely, from kappa=0.50-.04.
101

This study highlights the differences in orthodontic analyses among various orthodontists
and the variability in the reliability of orthodontic diagnosis and treatment planning.
Current issues
In orthodontics today, there is growing debate over whether or not CBCT images
should be taken for routine diagnosis and treatment planning or utilized judiciously in
cases in which the diagnostic benefits are proven to outweigh the risks. Orthodontic
literature falls short in clearly outlining which cases should be referred for CBCT
examination. It is often recommended that CBCT scans be utilized in cases in which
traditional radiographs lack the information needed to make an accurate diagnosis. In
2010, the AAO issued a statement proclaiming that while “there may be clinical
situations where a CBCT radiograph may be of value, the use of such technology is not
routinely required for orthodontic radiography”.
102
However, such clinical situations
have not been formally outlined by the AAO or thoroughly investigated in orthodontic
studies.
A recent study evaluating the use of CBCT imaging in postgraduate orthodontic
programs in the United States and Canada found that of the 36 programs (52.2%) that
30
responded to the survey, 83.3% had access to a CBCT unit. Of these, 4 of the programs
(18.2) reported using CBCT for every patient, whereas 81.8% used them for specific
diagnostic purposes. Impacted and supernumerary teeth, TMJ findings, and craniofacial
abnormalities made up the majority of CBCT use for specific diagnostic purposes.
Regular use was reported by 73.3% of programs. In 31.8% of the programs, residents
were responsible for reading the scans and reporting abnormal findings.
103

Along with the introduction of CBCT data into the dental field comes the question
of who holds legally responsibility for the information contained in these images. Some
suggest that the complex and immense data contained in the scan requires interpretation
by a professional trained in the field.
8
Studies have found that there is significant error in
interpretation of the images by untrained clinicians, leading to high rates of missed
diagnoses in addition to false negatives or false positives.
104

To date, there are no evidence-based guidelines regarding the routine use of
CBCT imaging in orthodontics. One important determinant of establishing a protocol will
be to determine if routine orthodontic diagnosis and treatment planning is affected by
information provided by 3-D imaging. This study seeks to analyze the effect of cone-
beam computed tomography (CBCT) imaging on orthodontic diagnosis and treatment
planning.
31
Chapter 3: Hypothesis
Goals of the study:
This study seeks to evaluate if CBCT imaging provides information that will influence
orthodontic diagnosis and treatment planning.
Hypotheses:
1. CBCT imaging will provide additional information that will influence orthodontic
diagnosis to a statistically significant degree (p<.05).
2. CBCT imaging will provide additional information that will influence orthodontic
treatment planning to a statistically significant degree (p<.05).
3. Statistically significant differences in orthodontic diagnosis and treatment
planning will be seen when comparing orthodontic examiners with more
experience using CBCT and those with less experience (p<.05).
32
Chapter 4: Materials and Methods

In this investigation, the orthodontic records of 38 patients, presenting
consecutively to the University of Nevada, Las Vegas postgraduate orthodontic
department, were evaluated by 4 orthodontic examiners. Each examiner diagnosed and
planned treatment for each case at 3 separate points in time. Conventional orthodontic
records (panoramic and lateral cephalometric radiographs, intra-oral and extra-oral
photographs) were provided for the first two analyses (T1 and T2) and the third analysis
(T3) included CBCT data [Hitachi CB Mercury (Hitachi Medical Systems America,
Twinsburg, OH)] in addition to conventional records. The diagnoses and treatment plans
with and without 3-D imaging were compared to determine if CBCT data altered the
orthodontic diagnoses and treatment plans.
Examiners completed questionnaires (Figure 6) to indicate their diagnosis and
preferred plan of treatment for each of the 38 cases at the 3 different points in time, each
one month apart. Each patient was de-identified and the order of patients was
randomized between each data set to discourage recollection of the cases. A time period
of 1 month elapsed between the distribution and completion of the diagnosis and
treatment plans for each set of data. Examiners completed the questionnaires on their
private computers. They were given the latitude to choose their own approaches to
diagnosis. The rationale for doing so was to allow the orthodontists to rely on their
familiarity and experience, rather than require conformity of analyses, thereby
introducing a new routine that could influence their ability to diagnose and plan
treatment. The orthodontists were asked to provide detailed treatment goals and plans,
33
including phases of therapy, all additional treatment procedures (such as extractions and
frenectomy) and specific biomechanics including appliance prescriptions and archwire
designs, with detail on management of archform, anteroposterior, transverse and vertical
dimension. The examiners were asked to use the same level of detail when performing
the assessments at the three points in time.
Figure 6: Diagnosis and treatment planning questionnaire

Case # :
Radiographic findings:
Summary/Problem List:
Goals:
Diagnosis (comprehensive diagnostic statement):
Skeletal : Class I Class II Class III
Dental : Right Class I Class II ¼ ½ ¾ full Class III ¼ ½ ¾ full
Left Class I Class II ¼ ½ ¾ full Class III ¼ ½ ¾ full
Treatment Plan:

To evaluate the CBCT data, each examiner was given a practical tutorial session
of approximately 20 minutes in length detailing the use of Invivo Dental™version 5.0
(Anatomage, San Jose, CA). The tutorial outlined how to conduct reformatting of the
images, view the data in different soft and hard tissue windows, use the volume render
and sectional views, and what to look for in the evaluation. A checklist was distributed to
assist in guiding the evaluation of the craniofacial structures while conducting the 3-D
34
analysis (Figure 7). Examiners were advised to ask questions if any confusion arose
regarding the use or interpretation of the 3-D software.
Figure 7: CBCT checklist
Anatomic Feature Example of Additional Information provided by CBCT
3D view of dentition-
SV and VR
Supernumerary teeth
Unusual tooth positions not shown on pan
Unusual tooth morphology (eg 2-rooted canine)
Root shortening
Tooth tip and torque problems
Dental crossbites
3D view of skeleton Subtle asymmetries
Cortical perforations (due to abscess/pathology)
Skeletal crossbites
Cleft palate
Alveolar ridge Alveolar bone height and width (thin alveolar bone limiting
expansion/incisor proclination)
Fenestrations and dehiscences (periodontal disease)
Adequate bone apical to incisors to resolve deep overbite by
intrusion of incisor?
Enostosis (dense bone around root apices, preventing tooth
movement, usually in mandible)
Variations/incompatability between Mx and Md archform
Temporomandibular joints Shape of condyle / Erosions of condyle
Flattening/remodeling of condyle
Condylar position (centered in fossa?)
Uniform joint space between condyle and fossa?
Fossa morphology
Unusual condylar morphology
Airway and Sinuses Nose – inflamed nasal mucosa and obstructions
Sinuses – fluid/mucosa/polyps
Throat – long palate and space posterior to tongue
Facial soft tissues Asymmetries
Soft tissue thickness / Lip support

Examiner Selection
All of the examiners were part- or full-time faculty members at accredited
postgraduate orthodontic programs. Three examiners are also full-time private practice
35
clinicians. A demographic questionnaire (Figure 8) given to each examiner was used to
evaluate clinical experience and familiarity with cone beam computed tomography.
Examiners with minimal clinical or educational CBCT experience were given an
experience score of one. Those with moderate or extensive CBCT experience were given
a score of 2 (moderate) or 3 (extensive). Assessment of experience was based on the
demographic information provided.
Figure 8: Examiner demographic questionnaire

Demographic Information
Number of years in practice-_______________
Year of graduation from orthodontic residency program- _____________
Location of residency training- ________________
Location of practice/ teaching institute if academic instructor ______________
Have you received any training in diagnosis and treatment planning using CBCT
imaging? Y / N
If yes, please explain-_
Do you have any clinical experience with CBCT imaging- Y / N
If yes, please explain-______________________________

Patient Selection

Sixty patient records were initially documented from the postgraduate orthodontic
department. These 60 patients were comprised of the first 20 patients that presented in the
years 2008, 2009, and 2010. Of the 60 patients, 22 were excluded. Exclusion criteria
included a lack of complete orthodontic photos and radiographs, unclear photos, and
improper cephalometric positioning.
Orthodontic records

Patient records included a set of 3 extra-oral photos and 5 intra-oral photos. The
extra-oral photos consisted of one photo in frontal repose, one frontal smiling photo, and
one photo of the patient’s profile. Intra-oral photos included one frontal photo with the
36
patient in centric occlusion, two photos of the buccal occlusion (one right, one left), and
two occlusal photos (one maxillary, one mandibular).
Panoramic and lateral cephalometric images were generated from the CBCT data
and included in the records at T1, T2, and T3. The lateral cephalogram was traced using
Dolphin Imaging 10.1 software (Dolphin, Chatsworth, California, USA) by one
orthodontic resident (S.C.). The cephalograms were traced using the Steiner, Tweed, and
Wits analyses and examiners were given the option to select another cephalometric
analysis if they so desired. The examiners were not provided with orthodontic study
models or information obtained in the clinical exam, including the patient’s chief
complaint, medical or dental history. They were asked to use their best judgment when
creating the diagnosis and treatment plans.
Case Scoring
Diagnostic and treatment planning differences at T1, T2, and T3 were scored by
one referee (S.C.) who evaluated all cases at two separate points in time to ensure
conformity of evaluation. The diagnosis and treatment plans were scored separately for
each case and each evaluation compared the diagnosis or treatment plan at one point in
time against another point in time (T1, T2, or T3).
The scoring was noted as: no difference (score=0), minor difference (score =1),
major difference (score=2), or misdiagnosis/missed diagnosis/potential harm to the
patient (score=3) for changes observed in both the diagnosis and treatment plan (Table 3).
The category of “no difference” included patients that had no different or additional
diagnostic or treatment comments. The category of “minor difference” included patients
37
that had new comments that were of notation only and did not have an effect on the
overall diagnosis or treatment plan. Examples of minor differences are: presence of
idiopathic osteosclerosis, presence of mandibular tori, and insignificant variations such as
Class II ½ step molar versus Class II ¼ step molar in 2 different timepoints. In this
category both the orthodontic diagnosis or treatment plan would remain the same or
change to a negligible extent. The category of “major difference” included patients that
had new findings that would lead to a different or additional diagnosis or a deviation of
any type from the original treatment plan. Examples include; discovery of supernumerary
teeth, need for additional treatment procedures, changes in extraction patterns, addition of
appliances such as a rapid palatal expander, changes in biomechanical approaches, and
delay of treatment. The last category was for misdiagnosis, missed diagnosis or a
diagnosis or treatment plan that could potentially harm the patient. Examples include
movement of an impacted canine into the root apex of the adjacent lateral incisor,
intrusion of maxillary incisors into the anterior nasal spine, or missed pathology such as a
cyst.
Statistical analysis

Each evaluation of change in diagnosis or treatment plan was performed by
comparing one timepoint to another. For ease of interpretation, the timepoints were
labeled T1, T2, and CBCT (T3). An analysis comparing T1 and T2 was designated
T1_T2, whereas evaluation of T2 versus CBCT was designated T2_CBCT. Diagnostic
changes were abbreviated (Dx) and treatment plan changes were abbreviated (Tx).
Descriptive statistics for our three timepoint variables T1_T2, T1_CBCT and T2_CBCT
38
Dx and Tx and 3-D experience score are presented on Table 4 and 5 for the four raters.
The variables were tested for normality with Kolmogorov-Smirnov test. None of the
variables passed the normality test (p<.001). To test for overall differences among raters
in T1_T2, T1_CBCT and T2_CBCT Dx and Tx, Friedman’s test was used to compare 4
non-parametric related samples. To test for differences between the two less experienced
orthodontists and the moderate/experienced orthodontists, Wilcoxon Signed Ranks test
was used to compare two non-parametric related samples. To test for differences between
the two less experienced orthodontists and the moderate/experienced orthodontists, we
used Wilcoxon Signed Ranks test to compare two non-parametric related samples.
Table 3: Case scoring
Examples of changes in
diagnosis
Examples of changes in
treatment plan
Score = 0 No difference No difference
Score =1
(minor
differences)
Mandibular tori
Degree of overbite / overjet
< ½ step in molar diagnosis
Idiopathic sclerosis

+/- use of elastics
Type of headgear
Type of RPE
Prosthetic tooth replacement options

Score =2
(major
differences)
Location of impacted tooth
Skeletal classification-I/II/III
> ½ step in molar diagnosis
Presence of a supernumerary
tooth
Severity of root resorption

+/- Headgear
+/- RPE
Change in extraction pattern
+/- Surgical treatment
Delay of treatment
Need for additional treatment
procedures
Score = 3
(misdiagnosis,
missed
diagnosis,
harm to
patient)
Missed pathology
New findings:
-Sinus
-Nose
-Airway
-TMJ

Referral to specialist prior to
treatment
Extraction of a tooth because of root
resorption/bone levels
Harmful movement of teeth (out of
bone/into another tooth)

39
Chapter 5: Results
Of the 38 orthodontic patient records selected for analysis in this study, 23 were
female and 15 were male. The average age was 19.5 years for females and 14.5 years for
males with an overall average age of 17 years old. The four orthodontic examiners had
an average of 22.25 (range 15-31) years of clinical experience. Two examiners reported
having very minimal experience with cone beam imaging (experience score=1). One
examiner described himself as moderately proficient with CBCT (score=2), and one
identified himself as strongly proficient (score=3).
Descriptive statistics for T1_T2, T1_CBCT and T2_CBCT Dx and Tx and 3-D
experience score are presented on Tables 4 and 5 for the four raters. Figures 9-14
demonstrate a this data in graphic form.
Table 4: Frequency for differences in diagnosis

Variables Score Rater #1 Rater #2 Rater #3 Rater #4
0 89.5% 84.2% 94.7% 86.8%
1 7.9% 15.8% 2.6% 13.2%
2 0% 0% 2.6% 0%

Dx
T1_T2
3 2.6% 0% 0% 0%
0 92.1% 36.8% 36.8% 65.8%
1 7.9% 21.1% 34.2% 18.4%
2 0% 34.2% 7.9% 0%

Dx
T1_CBCT
3 0% 7.9% 21.1% 15.8%
0 84.2% 31.6% 36.8% 63.2%
1 10.5% 23.7% 34.2% 21.1%
2 2.6% 36.8% 7.9% 0%

Dx
T2_CBCT
3 2.6% 7.9% 21.1% 15.8%
3-D
experience
1 2 3 1

40
Table 5: Frequency for differences in treatment planning
Variables Score Rater #1 Rater #2 Rater #3 Rater #4
0 57.9% 55.3% 73.7% 47.4%
1 21.1% 21.1% 13.2% 31.6%
2 18.4% 23.7% 13.2% 18.4%
Tx
T1_T2
3 2.6% 0% 0% 2.6%
0 44.7% 55.3% 60.5% 50.0%
1 21.1% 10.5% 21.1% 26.3%
2 34.2% 23.7% 18.4% 18.4%
Tx
T1_CBCT
3 0% 10.5% 0% 5.3%
0 47.4% 81.1% 55.3% 44.7%
1 26.3% 2.7% 23.7% 21.1%
2 23.7% 5.4% 21.1% 28.9%
Tx
T2_CBCT
3 2.6% 10.8% 0% 5.3%
3-D
experience
1 2 3 1

Of all 38 cases examined by the 4 examiners (152 cases total), a total of 20 cases
yielded a diagnosis, treatment planning, or both diagnosis and treatment planning scores
of 3 (missed diagnosis, misdiagnosis, or harm to the patient). Table 6 illustrates these
findings.
Table 6: Diagnosis and treatment planning differences: score = 3

Diagnostic changes for
all examiners (n=18)
Treatment plan changes
for all examiners
(n=7)
Score = 3 -Sinus findings (n=9)
- Nasal
findings/deviated
septum (n=5)
-TMJ findings (n=2)
-Airway findings (n=1)
-Impacted tooth was
not identified (n=1)

-Referral to specialist
prior to beginning
treatment (n=5)
-Surgical treatment plan
only (n=1)
-Identification of severe
root resorption
significantly impacting
treatment plan (n=1)

41
Figure 9: Frequency of scoring differences in diagnosis T1_T2

Figure 10: Frequency of scoring differences in diagnosis T1_CBCT

Score

Score

42
Figure 11: Frequency of scoring differences in diagnosis T2_CBCT

Figure 12: Frequency of scoring differences in treatment planning T1_T2

Score

Score

43
Figure 13: Frequency of scoring differences for treatment planning T1_CBCT

Figure 14: Frequency of scoring differences in treatment planning T2-CBCT

Score

Score

44
Overall inter-rater comparison (4 examiners)

There were no significant differences among the 4 raters in T1_T2 Dx (p=.629),
or Tx (p=.137). There were significant differences in T1_CBCT Dx (p<.001) and
T2_CBCT Dx (p<.001). However, there were no statistically significant differences in
T1_CBCT Tx (p=.615) or T2_CBCT Tx (p=.050). Note T2_CBCT Tx p-value was .050,
below .10.
Inter-rater comparison based on 3-D experience
The examiners were divided into two groups, those with CBCT experience
(experience score= 2 or 3) and those with minimal experience (score=1). There were
statistically significant differences between orthodontists with experience compared to
orthodontists without experience in T1_CBCT Dx (p<.001), T2_CBCT Dx (p<.001) and
T2_CBCT Tx (p=.022).
Table 7: Differences in diagnosis and treatment planning based on experience
Test Statistics(c)

DT1-
DT2_E -
DT1-DT2
DT1-
DCBCT_E
- DT1-
DCBCT
DT2-
DCBCT_
E - DT2-
DCBCT
TT1-
TT2_E -
TT1-TT2
TT1-
TCBCT_E -
TT1-
TCBCT
TT2-
TCBCT_E -
TT2-
TCBCT
Z
-.246(a) -4.302(b) -4.273(b) -1.292(a) -.794(a) -2.298(a)
Asymp.
Sig. (2-
tailed)
.806 .000 .000 .196 .427 .022
a Based on positive ranks.
b Based on negative ranks.
c Wilcoxon Signed Ranks Test

Non parametric correlations between experience and diagnosis and treatment
planning

The examiner’s experience with 3D was scored as follows (1=minimal,
2=moderate, 3=experienced). There was a significant correlation between prior
45
examiner’s experience with 3-D imaging and the differences in diagnosis between 2-D
and 3-D (T1_CBCT R=.390 p<.001; T2_CBCT R=.348; p<.001). Please note T2_CBCT
Tx p-value was below 0.10.
Table 8: Correlations between CBCT experience and diagnosis and treatment
planning

Dx
T1-T2
Dx
T1-
CBCT
Dx
T2-
CBCT
Tx
T1-T2
Tx
T1-
CBCT
Tx
T2-
CBCT
Spearman's
rho
Experi
ence
Correlation
Coefficient
-.057 .390(**) .348(**) -.146 -.102 -.149
Sig.
(2-tailed)
.482 .000 .000 .072 .210 .067
N
152 152 152 152 152 152

** Correlation is significant at the 0.01 level (2-tailed)
46
Chapter 6: Discussion

Differences in diagnosis and treatment planning using conventional records
No significant differences were found when examiners repeated diagnosis
(p=.629) and treatment planning (p=.137) using conventional records. Comparison of the
differences in diagnosis and treatment planning at these two timepoints yielded the
highest frequency of low scores (score=0 or 1). This data demonstrates that among the 4
examiners minimal deviations in treatment planning and diagnoses using conventional
records were present. Given that the orthodontic records at T1 and T2 were identical, no
differences in diagnosis and treatment planning were anticipated.
It can be deduced that there is a level of consistency in diagnosis and treatment
planning within an orthodontist when provided with identical records data. A previous
investigation sought to evaluate the examiner reliability in the assessment of various
parameters of malocclusion observed both clinically and on study models. The findings
indicated that the reliability among the different examiners was dependent on the
malocclusion.
105
These differences suggest that the presenting malocclusion plays an
important role in determining if there will be concordance in diagnoses among
orthodontists. Intra-examiner comparisons of evaluations of malocclusion yielded the
smallest differences (kappa median 0.82), suggesting that given the same data, an
orthodontic diagnosis may be susceptible to no/minor changes when evaluated by the
same individual.
105
In contrast to this previous investigation, the current study did not
take into account the severity of the malocclusion. In future studies, the severity of the
47
malocclusion should be considered since it has the potential to influence diagnosis and
treatment planning differences among examiners.
Inter- and intra-examiner discrepancies in diagnosis and treatment planning have
been shown to exhibit some degree of variability. In one study, inter-rater agreement for
three orthodontic parameters (complexity, case outcome, and treatment need) varied
widely among examiners, from kappa=0.50-.04.
101
The reliability of a single calibrated
examiner in this study was kappa=0.90 for pretreatment and kappa=0.83 for post-
treatment evaluations. This finding demonstrates the greater precision in diagnosis among
an individual with a calibrated means of assessing a given case. In the current study, the
diagnosis and treatment planning questionnaire would serve such a purpose, however all
orthodontic examiners did not describe the diagnosis and treatment plan to the same level
of detail. Instead, the examiners were asked to complete the diagnosis and treatment
planning using their own approaches. This was prescribed to allow each orthodontist to
use their own experience and familiarity, in order to avoid the confounder of new
protocols. Additionally, there was variation in the level of detail provided within an
examiner, suggesting that these discrepancies may be accountable for differences arising
in diagnosis and treatment planning between the timepoints. This variation in the level of
detail described for each case suggests that a more detail-oriented orthodontist may be in
a better position to take full advantage of CBCT imaging. Some variation in the level of
detail provided for each case may be attributed to examiner burnout. On any given day a
clinician may choose to approach treatment from a slightly different point of view,
making minor changes not affecting the overall case outcome.
48
Differences in diagnosis and treatment planning at all timepoints
At the three points in time, differences in treatment planning and diagnosis were
noted. Previous research supports both a lack of, and a strong reliability in orthodontic
diagnosis and treatment planning. Some research shows high inter-examiner reliability
and agreement between information obtained for diagnostic purposes.
98
Other studies
have found that inter-examiner reliability for various diagnostic factors depends on the
malocclusion.
99,100
Additional influences to consider are orthodontic education and
experience. These differences in diagnosis and treatment planning suggest that the
presenting malocclusion plays an important role in determining if there will be
concordance in diagnoses within orthodontists, but many more factors may also be
influential. Orthodontic treatment decisions made using dental casts have been shown to
have statistically significant differences in extraction patterns when viewing the identical
information at two points in time.
106
In orthodontics, there is variability in the reliability
of diagnosis and treatment planning.
Given the nature of the study and greater familiarity with conventional
radiographs, it is possible that the examiners invested more time and greater attention to
the CBCT data than the 2-D radiographs. Greater attention to detail may have lead to an
increase in diagnostic findings in CBCT, thereby creating a difference in diagnoses.
There were significant differences in the diagnoses when comparing conventional
records (T1 and T2) to CBCT data (p<.001) among the examiners. The vast information
provided by the CBCT data was likely to be analyzed differently by each examiner,
leading to changes in diagnosis and treatment planning. The level of detail provided by
49
CBCT imaging is far superior to 2-D radiographic methods. Accordingly, reformatting
CBCT images for ideal visualization most likely enabled some examiners to better view
structures without distortion and superimpositions. Clinical implications of this finding
suggest that using 2-D radiographs may not be providing as much info as 3-D leading to
inferior diagnoses or missing information.
Interestingly, despite the changes in diagnoses gained upon addition of the CBCT
data, there were no statistically significant changes in treatment plans. The lack of
statistically significant differences in treatment plans made using traditional records and
3-D data suggests that the additional diagnostic information provided by CBCT did not
impact orthodontic treatment planning. However, another valid explanation is that
orthodontists have not learned to fully apply all of the information from CBCT into
treatment planning.
In this study, a score of 3 was given in one case of an unidentified impacted tooth.
Identification of an impacted tooth is critical to providing orthodontic care and could
pose harm to the patient in the future if not initially diagnosed. In another case, the
severity of root resorption was identified as severe when CBCT imaging was evaluated.
The examiner did not consider root resorption to be a notable finding when evaluating the
dentition using 2-D radiographs. Upon finding the root resorption to be much more
severe when viewed using reconstructed CBCT images, the examiner changed the
treatment plan significantly. Literature has shown that root resorption is underestimated
using 2-D radiographs.
72
These findings underscore the importance of taking advantage
of CBCT imaging in orthodontic cases involving impacted teeth.
50
The role of various diagnostic factors in influencing treatment planning is critical
to understanding the value of CBCT imaging. Of 139 consecutive CBCT scans taken
from 134 patients, incidental maxillary sinus findings were found in 65 of the CBCT
images (46.8%).
16
The large incidence of sinus findings in the general population,
suggests that some of these CBCT findings are rather common. However, clinically
patients rarely complain about sinus issues, and if so, this may not be expected to change
an orthodontic treatment plan. In fact, in many cases sinus findings may go completely
unnoticed by the patient and clinician. However, in other cases these findings may be of
particular interest to the orthodontist. Mouthbreathing is a common etiology of
malocclusion. CBCT may provide insight into the appropriate diagnosis and treatment
planning strategies aimed specifically at targeting the etiology of the malocclusion. In
cases of sinus and other extra-oral abnormalities, the treatment often lies outside the
scope of orthodontic care.
A CBCT study of 500 patients revealed incidental findings in 24.6% (123 of 500)
patients. Most of these finding were in the airway area (18.2%), followed by the TMJ
(3.4%), endodontic findings (1.8%) and others (1.2%).
11
Abnormalities seen in sinuses
and airways are notable diagnostic changes, but would most likely not impact the
majority of orthodontic case treatment as stated above. Similarly, a clearer view of an
impacted canine on CBCT may provide greater information for localization and surgical
exposure, but also may not impact a written treatment plan. TMJ abnormalities can
greatly affect planned orthodontic treatment. However, in cases of TMJ abnormality, the
clinical exam is often critical and may define the course of treatment. A TMJ finding on
51
CBCT may not impact an initial treatment plan if the patient was unaware of any
pathology and presented asymptomatically. However, this CBCT information would be
helpful in monitoring treatment progress and the status of the TMJ throughout treatment.
This study found that the majority of diagnosis and treatment planning changes
yielding a score of 3 were attributed to sinus, nasal, airway, and TMJ findings and
associated referrals to specialists. This data suggests that extra-oral visualization of
structures with CBCT imaging provides information to the clinician that may not directly
impact orthodontic treatment. Although the observed findings are notable, they may not
be relevant to the clinician and thus, taken alone may not justify the use of CBCT. These
cases also highlight the importance of the clinical exam in determining patient symptoms.
It is important to identify if changes in treatment planning at separate points in time are
due to common, slight variations in clinical judgment or misdiagnosis.
If the treatment plans were not completed in enough detail, it is likely that many
potential changes in plans would go unrecognized since they were not specifically
addressed in the evaluation. If examiners anticipated treatment going one way but had to
deviate from the original plan midway through treatment, these changes would not have
been reflected in the this study.
The effect of experience on diagnosis and treatment planning
There were statistically significant differences between orthodontists with
experience (score 2 to 3) compared to orthodontists without experience in evaluating
diagnosis between 2-D and 3-D and treatment plans at one timepoint [T1_CBCT Dx
(p<.001), T2_CBCT Dx (p<.001) and T2_CBCT Tx (p=.022)]. The addition of more
52
cases and examiners may be effective in revealing greater differences in diagnoses and
treatment plans.
There was a significant correlation between prior examiner’s experience with 3-D
imaging and the differences in diagnosis between 2-D and 3-D (T1_CBCT R=.390
p<.001; T2_CBCT R=.348; p<.001). Although literature on this topic is sparse, a
previous study evaluating examiner differences in the assessment of different
malocclusions found that greater contrast was seen between the least experienced
examiner than the two orthodontically more experienced examiners when evaluating the
malocclusions.
105
This suggests that examiners with similar years of experience may be
more likely to assess orthodontic malocclusions in a similar manner. Similar comparisons
can be made to the present study in that examiners with greater CBCT experience may
have been more likely to assess cases similarly, finding noteworthy data in the CBCT
images. Those examiners with greater familiarity with CBCT imaging were most likely
adept to interpreting and manipulating the images, which may have lead to an extraction
of even more data when compared to those examiners less familiar with CBCT imaging.
This is supported by the finding that significant correlation exists between an examiner’s
experience with 3D and the differences in diagnosis between 2-D and 3-D imaging. This
study found that orthodontic examiners with moderate or greater levels of familiarity with
CBCT were more likely to distinguish differences in diagnoses made with 2-D and 3-D
imaging.
The less experienced orthodontic examiners in this study were not found to have
as great a discrepancy between the diagnoses made at the three points in time. This is
53
most likely consistent with both examiners lacking of formal training and experience with
cone beam software and data, leading to an incomplete ability to fully interpret the data
and missed diagnoses. One would anticipate that a clinician unfamiliar with CBCT
imaging would be more likely to miss diagnoses or have false-positive findings.
Professional guidelines
One issue associated with integrating CBCT into routine dental care is the
ambiguity surrounding the individual responsible for the information contained in the
scan and how much training is needed to be able to fully interpret the data. Training
courses, seminars, and continuing education lectures are available to teach orthodontists
how to use CBCT, however many orthodontists are unfamiliar with this information.
Integrating CBCT courses into graduate orthodontic education may be a useful way to
familiarize orthodontic professionals with the abundance of information present in 3-D
data. Education and extensive training in the use of CBCT data may be critical in fully
defining the benefits of this technology in future studies evaluating changes in diagnosis
and treatment planning.
CBCT images incorporating the full field of view are of particular concern for
clinicians less familiar with interpreting 3-D radiographs. Studies have found that there is
significant error in interpretation of CBCT images by untrained clinicians, leading to high
rates of missed diagnoses in addition to false negatives or false positives.
104
The Ionising
radiation (Medical Exposure) Regulations does no not explicitly identify who takes on
the responsibility to report CBCT data and states that it is generally regarding as an
‘operator role’.
107
Some suggest that the complex and immense data contained in the
54
CBCT data requires interpretation by a professional specifically trained in the field.
8

Anyone interpreting the data should be appropriately trained. Maxillofacial and general
radiologists have received advanced training and are thought to be adequately delegated
to this task. However, the question remains as to whether or not dental specialists or
general practitioners utilizing these scans have the necessary training to conduct such
interpretations.
108
Further studies are needed to evaluate the level of education and
training needed required to fully interpret CBCT images.
Other studies have reiterated the importance of obtaining thorough training in
order to understand and utilize CBCT to the fullest degree. This study reiterates the
importance of proper training and education in order to extract the most information from
CBCT imaging.
55
Chapter 7: Limitations
Examiner Limitations
Several limitations were inherent to this study due to the relatively small sample
size and limited number of orthodontic examiners. The patients were taken from a single
university setting, and may not accurately represent a typical private practice. The limited
number of orthodontic cases and examiners may have affected the statistical analysis and
power of the study.
The month allotted between the 3 time points may not have been adequate to allow
each instructor to approach the evaluation of cases at the subsequent time point from a
fresh, unbiased point of view. Examiners may have been able to recall the previous
treatment plan and diagnosis. This recalled information could be used when completing
the questionnaire at the next time point, especially in the more obscure cases with
notable, rare findings.
A discrepancy in the level of detail in the diagnosis and treatment planning was
likely to occur due to examiner burnout. If a greater number of cases and examiners were
included in the study, it may be necessary to allow more time between each timepoint to
minimize examiner burnout. Examiner burnout would most likely have manifested itself
as a less thorough analysis of cases at T2 than T1, and even less thorough analysis at T3,
than both T1 and T2. However, since each examiner was given information regarding the
purpose of the study, greater attention to detail may have been paid to the final CBCT
data set. A specific checklist was given to the examiners regarding the interpretation and
evaluation of the cone beam data. This may have lead to greater time spent completing
56
the evaluations at this time point. Inherent instructor bias on the utility of CBCT based
on their own previous experience or knowledge may have caused changes in the
diagnosis and treatment plans made using CBCT.
Patient Records

Patient records did not include a chief complaint, diagnostic study casts, or a
clinical examination. A chief complaint is an important principal in determining what the
patient seeks to gain from orthodontic treatment. In some orthodontic cases, this patient
information will sway the treatment towards one particular plan or another.
A clinical examination allows the orthodontist to evaluate the teeth and jaws in
function. This can be important in determining the presence of CO-CR shifts, TMJ
sounds, deviations in jaw opening and closure, and oral habits. Another vital aspect of
the clinical exam is patient dialogue. Patient reports of TMJ dysfunction, previous
medical/dental history, and habits are all important discoveries during the clinical
diagnosis because they may not be evident for detection otherwise. The lack of a clinical
exam may influence the diagnosis and treatment planning. Examiners may assume such
issues were not present in the patient unless there was clinical evidence documented in
the photos or radiographs. This most likely would have affected the analysis at each time
point in the same way within a single examiner, thus would not contribute as greatly to
changes in the diagnosis and treatment planning at the 3 timepoints.

57
Chapter 8: Conclusion
Although the role of CBCT imaging in orthodontics is not clearly outlined at the
present time, it has been shown to serve as a valuable source of information to the
clinician for specific uses. To utilize cone beam scans in routine orthodontic care, it is
critical to identify the potential benefits in diagnosis and treatment planning. The findings
in this study suggest that CBCT provides additional diagnostic information, though the
impact of this additional information on altering orthodontic treatment planning needs to
be further investigated.
Examiner experience and training with CBCT imaging plays an important role in
the ability to extract useful diagnostic data. This research underlines the importance of
adequately educating clinicians on the uses, interpretation, and analysis of CBCT
imaging. Due to the amount of information available, it is critical that the orthodontist
completely understand all of the uses of CBCT data in order to gain maximum patient
benefits. Further studies with larger sample sizes are needed to specifically identify the
effects of CBCT on treatment planning. Knowledge of the potential impact of CBCT in
orthodontics will be of great value for clinicians in determining risk to benefit
assessments and for professional organizations to determine guidelines and
recommendations.

58
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Asset Metadata

Creator Chinea, Soraya (author)

Core Title The effect of cone beam computed tomography (CBCT) imaging on orthodontic diagnosis and treatment planning

School School of Dentistry

Degree Master of Science

Degree Program Craniofacial Biology

Publication Date 05/03/2011

Defense Date 03/22/2011

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

Tag cbct,Diagnosis,OAI-PMH Harvest,orthodontic,Radiography,treatment planning

Language English

Contributor Electronically uploaded by the author (provenance)

Advisor Paine, Michael L. (committee chair), Enciso, Reyes (committee member), Mah, James (committee member), Moon, Holly (committee member)

Creator Email soraya_c@hotmail.com,sorayachinea@gmail.com

Permanent Link (DOI) https://doi.org/10.25549/usctheses-m3827

Unique identifier UC1159713

Identifier etd-Chinea-4408 (filename),usctheses-m40 (legacy collection record id),usctheses-c127-456774 (legacy record id),usctheses-m3827 (legacy record id)

Legacy Identifier etd-Chinea-4408.pdf

Dmrecord 456774

Document Type Thesis

Rights Chinea, Soraya

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