View
39
Download
0
Tags:
Embed Size (px)
Citation preview
TREATMENT DETERMINANTS OF THE GINGIVAL SMILE
Jessica H. Cox, D.D.S.
An Abstract Presented to the Faculty of the Graduate School
of Saint Louis University in Partial Fulfillment
of the Requirements for the Degree of
Master of Science in Dentistry
2010
1
ABSTRACT
Objective: The purpose of this study is to determine
which dental, skeletal, and soft tissue characteristics
affect lip height and which characteristics affect lip
height changes during treatment. Materials and Methods:
Models for 200 randomly selected subjects were obtained and
used to calibrate the smiling photographs of each subject.
The photographs were then measured to determine the change
in gingival display that occurred during treatment. The
change in gingival display was used to create three groups:
those that obtained the greatest increase, greatest
decrease, and average change in gingival display. The
cephalometric radiographs were then traced for each subject
and digitized. The pre and post treatment cephalometric
radiographs of each subject were superimposed and a total
of 54 linear measures were made at each time point. The
measures were then compared using t-tests for intra-group
changes from T1 to T2 and an Analysis of Variance (ANOVA)
for inter-group comparisons at each time point.
Results: There were no significant differences between the
groups at the pretreatment time point. Paired t tests
revealed significant differences in 25 of the 27 vertical
measures within all groups from the pre treatment to post-
2
treatment time points. The horizontal measures indicated
more significant differences in the backward direction in
the greatest increase group than the other two groups. The
significant vertical difference between the groups at the
post-treatment time point was found between the average
change group and the greatest increase group at condylion.
The significant horizontal differences between the groups
were found between the greatest increase and greatest
decrease groups at the soft tissue lips. The lips moved
significantly backward in the greatest increase group while
they stayed relatively the same in the greatest decrease
group.
Conclusions: No pretreatment characteristic could be
identified to predict the tendency to experience an
increase or decrease in gingival display during orthodontic
treatment. The lips moved significantly backward in the
group that experienced an increase in gingival display
while they stayed relatively the same in the group that
experienced a decrease. Although not significant, other
general tendencies were apparent between the two extreme
groups. Further research is warranted.
TREATMENT DETERMINANTS OF THE GINGIVAL SMILE
Jessica H. Cox, D.D.S.
A Thesis Presented to the Faculty of the Graduate School
of Saint Louis University in Partial Fulfillment
of the Requirements for the Degree of
Master of Science in Dentistry
2010
i
COMMITTEE IN CHARGE OF CANDIDACY:
Professor Rolf G. Behrents,
Chairperson and Advisor
Professor Eustaquio Araujo
Assistant Professor Ki Boem Kim
ii
DEDICATION
To my loving husband, Wynne, who has made many
sacrifices to support me in my academic endeavors and whose
constant encouragement has enabled me to work through even
the most stressful times.
To my parents, who have encouraged me to strive for
excellence and have convinced me that, with work, I can
achieve any goal. Everything I have accomplished is due to
the confidence they have instilled and the encouragement
they continue to show.
To my family and friends, who have loved and supported
me throughout my education.
iii
ACKNOWLEDGEMENTS
! I would like to thank Dr. Behrents for giving me the
opportunity to continue my education in the specialty of
orthodontics and for his constant guidance and
encouragement during the past two and a half years.
I would like to thank Dr. Araujo for his encouragement
and guidance.
I would like to thank Dr. Kim for his support and
friendship.
Thanks to Dr. Heidi Israel for her assistance with the
statistical analysis.
!
!
iv
TABLE OF CONTENTS
List of Tables…………………………………………………………………………………………………………………vi
List of Figures…………………………………………………………………………………………………………………x
CHAPTER 1: INTRODUCTION…………………………………………………………………………………………1
CHAPTER 2: REVIEW OF THE LITERATURE…………………………………………………………4
Ideal Smile Esthetics…………………………………………………………………4
Definition of a Gummy Smile…………………………………………………5
Causes of a Gummy Smile Pre-Treatment………………………8
Sex Predilection………………………………………………………………………8
Musculature and Lip Incompetence……………………………8
Lip Length……………………………………………………………………………………10
Altered Passive Eruption………………………………………………10
Skeletal Disharmonies………………………………………………………13
Possible Causes of Gummy Smile Development
During Orthodontic Treatment……………………………………………18
Unexpressed Vertical Growth………………………………………18
Extrusive Forces……………………………………………………………………20
Anterior-Posterior Position of the Maxilla21
Treatments For Gingival Smiles………………………………………23
Treatments For Gingival Smiles Caused by
Altered Passive Eruption………………………………………………23
Treatments For Gingival Smiles Caused by
Incorrect Dental and Skeletal
Relationships……………………………………………………………………………25
Orthodontic Intrusion…………………………………………25
Implant Intrusion……………………………………………………26
Orthognathic Surgery……………………………………………28
v
Treatments For Gingival Smiles Caused by
Hyperfunction of the Lip Elevators……………………29
Muscle Resection………………………………………………………30
Botulinum Toxin…………………………………………………………31
Anterior Nasal Spine Implants……………………34
Summary and Statement of Thesis……………………………35
References……………………………………………………………………………………37
CHAPTER 3: JOURNAL ARTICLE
Abstract……………………………………………………………………………………………………………………41
Introduction…………………………………………………………………………………………………………43
Materials and Methods…………………………………………………………………………………46
Sample……………………………………………………………………………………………………………46
Sample Selection…………………………………………………………………………………46
Data Collection……………………………………………………………………………………51
Data Analysis…………………………………………………………………………………………57
Analysis of Error………………………………………………………………………………57
Results………………………………………………………………………………………………………………………58
Discussion………………………………………………………………………………………………………………77
Design……………………………………………………………………………………………………………77
Findings………………………………………………………………………………………………………78
Conclusions……………………………………………………………………………………………………………94
Appendix A………………………………………………………………………………………………………………96
Appendix B……………………………………………………………………………………………………………110
Literature Cited……………………………………………………………………………………………123
Vita Auctoris…………………………………………………………………………………………………………………124
vi
LIST OF TABLES
Table 3.1: Descriptive Statistics for the Change in
Gingival Display for the 200 subjects……………………49
Table 3.2: Description of Sample Groups……………………………………………50
Table 3.3: Landmark abbreviations and descriptions………………51
Table 3.4: Group 1 Pre-Treatment Vs. Post-Treatment
Landmark Measures…………………………………………………………………………61
Table 3.5: Group 2 Pre-Treatment Vs. Post-Treatment
Landmark Measures…………………………………………………………………………63
Table 3.6: Group 3 Pre-Treatment Vs. Post-Treatment
Landmark Measures…………………………………………………………………………65
Table 3.7: Descriptive Statistics for Significant
Horizontal Soft Tissue Landmarks at the Post-
Treatment Time Point…………………………………………………………………67
Table 3.8: ANOVA for Significant Horizontal Soft Tissue
Landmarks at the Post Treatment Time Point………67
Table 3.9: Tukey Post Hoc Multiple Comparisons Of
Significant Horizontal Soft Tissue Landmarks
at the Post Treatment Time Point…………………………………68
Table 3.10: Descriptive Statistics for the Significant
Vertical Landmark at the Post Treatment Time
Point…………………………………………………………………………………………………………69
Table 3.11: ANOVA for the Significant Vertical Measure at
the Post Treatment Time Point…………………………………………69
Table 3.12: Tukey’s Post Hoc Multiple Comparisons of the
Significant Vertical Landmark at the Post
Treatment Time Point…………………………………………………………………69
Table 3.13: Comparison of Mandibular Horizontal Measures
at T1 and T2…………………………………………………………………………………70
Table 3.14: Table 3.13 Comparison of Mandibular Vertical
Measures at T1 and T2………………………………………………………………71
vii
Table 3.15: Comparison of the Horizontal Maxillary
Landmarks at T1 and T2……………………………………………………………72
Table 3.16: Comparison of Vertical Maxillary Landmarks at
T1 and T2………………………………………………………………………………………………72
Table 3.17: Comparison of Horizontal Soft Tissue Landmarks
at T1 and T2………………………………………………………………………………………73
Table 3.18: Comparison of Vertical Soft Tissue Landmarks
at T1 and T2………………………………………………………………………………………74
Table 3.19: Comparison of Horizontal Dental Landmarks at
T1 and T2………………………………………………………………………………………………75
Table 3.20: Comparison of Vertical Dental Landmarks at T1
and T2………………………………………………………………………………………………………76
Table 3.21: Group Gender Percentages………………………………………………………88
Table 3.22: Mean Lip Length at T1………………………………………………………………89
Table 3.23: Mean Lip Length at T2………………………………………………………………89
Table 3.24: Change in Mean Lip Length from T1 to T2………………89
Table 3.25: Group Molar Classification…………………………………………………90
Table 3.26: Molar Classification Percentages…………………………………91
Table 3.27: Group Percentages of Class IIs………………………………………91
Table 3.28: Class II Division Percentages…………………………………………92
Table A.1: Pre-Treatment Horizontal Mandibular Measures
Descriptive Statistics……………………………………………………………96
Table A.2: ANOVA for Pre-Treatment Horizontal Mandibular
Measures……………………………………………………………………………………………………97
Table A.3: Pre-Treatment Vertical Mandibular Measures:
Descriptive Statistics………………………………………………………………98
Table A.4: ANOVA for Pre-Treatment Vertical Mandibular
Measures……………………………………………………………………………………………………99
viii
Table A.5: Pretreatment Horizontal Maxillary Measures:
Descriptive Statistics……………………………………………………………100
Table A.6: ANOVA for Pretreatment Horizontal Maxillary
Measures…………………………………………………………………………………………………100
Table A.7: Pretreatment Vertical Maxillary Measures:
Descriptive Statistics……………………………………………………………101
Table A.8: ANOVA for Pretreatment Vertical Maxillary
Measures…………………………………………………………………………………………………101
Table A.9: Pretreatment Horizontal Dental Measures:
Descriptive Statistics……………………………………………………………102
Table A.10: ANOVA for Pre-Treatment Horizontal Dental
Measures………………………………………………………………………………………………103
Table A.11: Pretreatment Vertical Dental Measures:
Descriptive Statistics…………………………………………………………104
Table A.12: ANOVA for Pretreatment Vertical Dental
Measures………………………………………………………………………………………………105
Table A.13: Pretreatment Measures for Non-significant
Horizontal Soft Tissue Landmarks:
Descriptive Statistics…………………………………………………………106
Table A.14: ANOVA for Non-significant Pretreatment
Horizontal Measures…………………………………………………………………107
Table A.15: Pretreatment Vertical Measures for Soft Tissue
Landmarks: Descriptive Statistics…………………………108
Table A.16: ANOVA for Pretreatment Vertical for Soft Tissue
Landmarks……………………………………………………………………………………………109
Table B.1: Post-Treatment Non-Significant Horizontal
Mandibular Measures: Descriptive Statistics.110
Table B.2: ANOVA for Post-Treatment Mandibular Horizontal
Measures………………………………………………………………………………………………111
Table B.3: Post-Treatment Non-Significant Vertical
Mandibular Measures: Descriptive Statistics…112
ix
Table B.4: ANOVA for Non-Significant Post-Treatment
Vertical Mandibular Measures……………………………………………113
Table B.5: Post-Treatment Horizontal Maxillary Measures:
Descriptive Statistics……………………………………………………………114
Table B.6: ANOVA for Post-Treatment Horizontal Maxillary
Measures…………………………………………………………………………………………………114
Table B.7: Post Treatment Vertical Maxillary Measures:
Descriptive Statistics……………………………………………………………115
Table B.8: ANOVA for Post-Treatment Vertical Maxillary
Measures…………………………………………………………………………………………………115
Table B.9: Non-Significant Post-Treatment Horizontal Soft
Tissue Measures………………………………………………………………………………116
Table B.10: ANOVA for Non-Significant Post Treatment
Horizontal Soft Tissue Measures…………………………………116
Table B.11: Post-Treatment Vertical Soft Tissue Measures:
Descriptive Statistics…………………………………………………………117
Table B.12: ANOVA for Post-treatment Vertical Measures for
Soft Tissue Landmarks……………………………………………………………118
Table B.13: Post-treatment Horizontal Dental Measures:
Descriptive Statistics…………………………………………………………119
Table B.14: ANOVA for Post-Treatment Horizontal Dental
Measures………………………………………………………………………………………………120
Table B.15: Post-Treatment Vertical Dental Measures:
Descriptive Statistics…………………………………………………………121
Table B.16: ANOVA for Post-Treatment Vertical Dental
Measures………………………………………………………………………………………………122
x
LIST OF FIGURES
Figure 3.1: Calculation of Gingival Display…………………………………47
Figure 3.2: Description of Measures of Gingival Display…48
Figure 3.3: Cephalometric Landmarks………………………………………………………53
Figure 3.4: Reference Planes…………………………………………………………………………55
Figure 3.5: Examples of Vertical and Horizontal Measures
from the Reference Planes…………………………………………………56
Figure 3.6: Graphical Representation of Changes from T1
to T2 for Group 1………………………………………………………………………81
Figure 3.7: Graphical Representation of Changes from T1
to T2 for Group 2…………………………………………………………………………82
Figure 3.8: Graphical Representation of Changes from T1
to T2 for Group 3…………………………………………………………………………83
1
CHAPTER 1: INTRODUCTION
!
!
As society becomes more esthetically conscious,
orthodontists are more challenged to produce not only
outstanding occlusions, but also outstanding esthetics.
Every minute detail is becoming more important in
separating the good from the great orthodontist. Recent
studies have indicated that the amount of gingival display
on smiling is very important to smile attractiveness.1 In
fact, Van der Geld et al. found that the amount of gingival
display was an important characteristic in a person’s own
satisfaction with their smile.2
When an excessive amount of gingiva is displayed upon
smiling, the term “gummy” is often used. While many
clinicians anecdotally point to the “lack of vertical
control” as the cause of orthodontically produced
“gumminess,” few studies that investigate the cause of post
treatment gummy smiles are present in the literature. Peck
et. al in 1992 found that the tendency of a person to
project a gummy smile was related to anterior vertical
maxillary excess, the muscular ability to raise the upper
lip higher than average when smiling, greater overjet,
greater interlabial gap at rest, and greater overbite.3 In
his study to determine the effectiveness of improving
2
patient smiles with orthodontic treatment and the
variability of improvement from orthodontist to
orthodontist, Mackley found that the orthodontist who was
most successful in producing greater post treatment smile
improvement scores decreased the stomion-incision
measurement while those that increased the stomion-incision
measure produced smiles with lower post treatment
improvement scores. He states, “This measurement is an
indication of the amount of gingival tissue that shows when
a person is smiling.” He also suggested that the most
successful orthodontist also increased the inclination of
the maxillary incisor to the NA line, while those that
produced less improvement decreased this measure. He
concludes that in order to “maximize our potential for
improving the smile, we must include in our treatment plan
an objective for moving the anterior teeth vertically to
improve their relationship to the smiling lip line.”4
While both of these studies indicate possible reasons
for an increase in gingival display, neither indicates any
pre-treatment skeletal or dental factors that might help a
clinician to predict the tendency to develop this
“gumminess” nor investigates post-treatment skeletal
factors that might be associated with this negative
condition. The purpose of this study is to determine which
3
dental, skeletal, and soft tissue characteristics effect
smiling lip height and which characteristics affect lip
height changes during treatment.
4
CHAPTER 2: REVIEW OF THE LITERATURE
Ideal Smile Esthetics
According to Hulsey, “A smile is one of the most
effective means by which people convey their emotions.”5
People with dental deformities often make every effort to
cover the displeasing portion with their lips. They rarely
smile or laugh, and thus might be viewed by others as
unfriendly.6 This might not only affect a person in their
personal life, but also professionally. According to Dale
Carnegie, one of the most important ways to win friends and
influence people is to smile.7 In fact, according to Van der
Geld et. al., studies have shown that higher intellectual
and social abilities have been attributed to individuals
with esthetic smiles.2 This is the reason that millions of
people seek orthodontic treatment each year, to produce a
smile they are pleased to view themselves and show to
others. As society becomes more esthetically conscious,
orthodontists are challenged to produce not only
outstanding occlusions, but also outstanding esthetics.
Every minute detail is becoming more important in
separating the good from the great treatment. However, in
order to create the best possible esthetics, orthodontists
must understand what the public at large views as beauty.
As Peck, Peck, and Kataja suggest, “We orthodontists tend
5
to forget that facial esthetics is a subject that interests
all people everywhere, and the ultimate source of esthetic
values should be the people and not just ourselves.”3 Within
recent years, many researchers have directed their studies
towards addressing this very question.
In their study to determine the average desirable
characteristics of an esthetic smile, Tjan et al. found
that the average esthetic smile has the following
characteristics: the full length of the maxillary anterior
teeth are displayed, the gingiva does not show, the incisal
curvature of the maxillary anterior teeth parallels the
inner curvature of the lower lip, the incisal curvature
either touches or almost touches the lower lip, the six
maxillary anterior teeth and the first or second premolars
are displayed, and the midline coincides with the philthrum
of the lip.8 Many other studies have confirmed these
findings.1,4,7
Definition of a Gummy Smile
Studies aimed at determining the characteristics of an
“ideal smile” have all stressed the importance of the
vertical placement of the maxillary incisors in relation to
both the upper and lower lips in the production of the most
esthetic smile. Van der Geld et al., found that the size of
the teeth, visibility of the teeth, and upper lip position
6
are critical factors in self perception of smile
attractiveness, as well as the color of the teeth and
gingival display. In their study, participants with 2 to 4
mm of gingival display were judged most favorable,2 however
the literature suggests varying threshold levels of
gingival display are tolerated before the amount of
gingival display negatively affects the perceived esthetics
of a smile.9 Kokich et al., first reported that 4.0
millimeters (mm) of gingival display represents the
threshold of acceptability, but more recently, using
smaller increments of measure, found 3 mm of gingival
display are considered unaesthetic by lay people.10 Chiche
and Pinault found that up to 3 mm of gingival tissue may be
displayed before esthetics is compromised.11 Geron and
Atalia found that gingival exposure is considered an
unaesthetic feature above 1 mm in the maxilla,12 and Hunt et
al. found the acceptable range for gingival exposure to lie
between 0 and 2 mm with an ideal of no gingival exposure.13
Ker et al. reported that while laypersons preferred 2.1 mm
of incisor coverage, +- 4 mm was within the range of
acceptiblity.1 In his study to determine whether the smiles
of orthodontically treated patients are as esthetically
pleasing as those of persons with “normal” occlusion,
7
Hulsey noted that the most attractive smiles were those in
which the upper lip rested at the height of the gingival
margin of the maxillary incisor.5 Perhaps the variation in
preference for the amount of gingival display is due in
part to a variation in the preference of gingival display
between male and female subjects. In their study, Gul-e-
Erum found the ideal gingival display to be 0 mm for males
and 2 mm for females.14
While the acceptable range of gingival exposure has been
debated, it is apparent that an excess of 4 mm of gingival
display on smiling is considered unaesthetic, and the
majority of the literature supports 0-1 mm of gingival
exposure as the ideal. For this reason, orthodontists
should pay special attention to the vertical placement of
the maxillary anterior teeth during treatment planning and
treatment. As Mackley asserts, “If we are going to maximize
our potential for improvement of the smile, we must include
in our treatment plan an objective that will improve the
relationship of maxillary incisors to the smiling lip line.
To do less than this is to do our patients a disservice.”4
When an excess of gingiva superior to the maxillary
anterior teeth is displayed upon full smile, it is termed a
gingival smile.3 The gingival smile is known by a variety of
terms including “gummy smile, high lip line, short upper
8
lip, and full denture smile.”3 Perhaps this variety in terms
is indicative of the many different causes of a gummy
smile.
Causes of a Gummy Smile Pre-Treatment
Sex Predilection
The tendency to have a gingival smile, appears to have
a sex predilection. According to a study by Tjan, Miller,
and The, low smile lines are predominantly a male
characteristic by 2.5 to 1, and high smile lines are
predominantly a female characteristic by 2 to 1.8 Peck,
Peck, and Kataja quantified these findings. They found
that at maximum smile, the upper lip line relative to the
gingival margin of the maxillary central incisors is
positioned 1.5 mm more superiorly in females than in
males.15 Similarly, Vig and Brundo found that maxillary
anterior tooth display was found almost twice as often in
women as in men.16 A literature search by Van der Geld and
Van Waas, further supports this assertion, indicating that
on average, the smile line was situated higher among women
than among men.17
Musculature and Lip Incompetence
The musculature can also have an effect. Peck et al,
found that the upper lip in gingival smile subjects
9
elevates superiorly 1 mm more from rest to maximum smile
than did a reference group.3 They also found that the
interlabial gap at rest position was much higher on average
(6.2mm) for the gingival smile line sample, than the
reference sample (3.0 mm).3 This indicates that lip
incompetence can be associated with a gingival smile line.
Upon further investigation, they found that 93% of the
gingival smile line group were lip incompetent at rest,
while only 63% of the reference sample were lip incompetent
at rest. When the likelihood ratio was calculated, it was
determined that the gingival smile line subjects were 5.5
times more likely to exhibit lip incompetence at rest than
the reference population.3 In his descriptive essay,
Matthews proposes that a person exhibiting an interlabial
gap at rest will also have a gingival smile line,6 however
while Peck et al. found that 93% of his gingival smile line
subjects also exhibited an interlabial gap at rest, he also
found that the opposite was not true. Only 56% of their
subjects with interlabial gaps at rest presented a gingival
smile line. Therefore, while Peck et al.’s study supports
the assertion that an interlabial gap at rest is highly
associated with the tendency to have a gingival smile line,
it also indicates that an interlabial gap at rest cannot be
considered predictive of the gingival smile phenomenon.3
10
Interestingly, Schendel et al. cite a large
interlabial distance as a common characteristic of vertical
maxillary excess, and these VME subjects also displayed an
excessive amount of the maxillary teeth and gingiva upon
smiling.18 These findings suggest that orthodontic
techniques that cause lip incompetence, might also have a
tendency to cause a gingival smile.
Lip Length
While lip length has been suspect in producing a
gingival smile line, Peck et al. found no difference in
upper lip length between the gingival smile and reference
groups, with both samples having a mean value of 22.3 mm.3
This is consistent with Schendel et al.’s report that
surgical patients with vertical maxillary excess have
normal lip lengths.18 In fact, in a study of 70 gingival
smile females, Singer found that the gingival smile group
actually had a significantly longer lip length than the
non-gingival smile sample.19
Altered Passive Eruption
Short clinical crown heights have also been reported to
increase the tendency to produce a gingival smile. Short
clinical crown heights can be due to altered passive
11
eruption, inflammation, and gingival enlargement. Active
eruption is the movement of the tooth toward the occlusal
plane. Passive eruption is the apical migration of the
gingival margin. Therefore, altered passive eruption, is
the delay in the apical migration of the epithelial
attachment toward the root surface of at the CEJ. According
to Waldrop, altered passive eruption can cause excessive
gingival display.20 Garber and Salama agree stating, “if the
teeth appear to be somewhat short and squat-meaning that
the vertical dimension appears to be too short as compared
with the horizontal dimension, the gummy smile is probably
due to altered passive eruption.”21 However, in Peck’s
study, the clinical crown height of the two groups was not
significantly different.3 As Garber and Salama point out, in
many cases, a gummy smile may be due to a combination of
vertical maxillary excess and altered passive eruption.21
Altered passive eruption can be classified into two
distinct types. In Type I, there is an excessive amount of
gingiva from the free gingival margin to the mucogingival
junction. In Type II, there is a normal amount of gingiva
as measured from the free gingival margin to the
mucogingival junction. Type I is further subdivided into
sub-categories A and B depending on the relationship of the
osseous crest to the cemento-enamel junction of the tooth.
12
In subcategory A, the dimension between the osseous crest
and the CEJ is greater than 1 mm, and therefore adequate
for the insertion of the connective tissue attachment
component of the biologic width. In subcategory B, the
osseous crest is in close proximity to the cementoenamel
junction, therefore adequate space for the connective
tissue attachment component of the biologic width is not
present, and the connective tissue appears to attach at the
same level as the cementoenamel junction. This seems
contrary to the biologic width, as the connective tissue
attachment must be present, yet cannot attach to the
enamel. According to Garber and Salama, clinical and
histological observations suggest that an increased
buccolingual dimension of the osseous form allows for
apical angulation of the bone crest from the gingival
aspect of the periodontal ligament side.21 While periodontal
connective tissue fibers normally run horizontally across
the osseous crest extending from the cementum to the
gingival, in this form of altered passive eruption, the
fibers run apically, parallel to this angular crest,
allowing the connective tissue fibers to insert into the
cementum just apical to the cementoenamel junction.
The biologic width is approximately 2.7 mm in
dimension.19,20
and is made up of 1 mm of junctional
13
epithelium, 1 mm of connective tissue attachment, and 1 mm
of sulcus depth.21 This “biologic width” is necessary for
the health of the periodontium and should not be violated
with restorative procedures. Due to its association with
this biologic parameter, the type and subcategory of
altered passive eruption present will determine the
treatment modality.21
In a study of 1025 patients, Volchansky et al. found
altered passive eruption in 12% of the patients.22 However,
more recently, Konikoff et al. found that 65% of post
orthodontic patients had less than ideal length to width
ratios in their anterior incisors.23 Therefore, after
thorough oral hygiene instruction, scaling and root
planning as needed, and a period of inflammation control,
patients with excessive gingival display should be
evaluated for altered passive eruption and the need for a
periodontal procedure.20
Skeletal Disharmonies
Growth of the maxilla is also related to gingival
smiles. According to Wilmar, the gingival smile line is
often associated with maxillary alveolar overdevelopment or
vertical maxillary excess (VME).24 Peck et al.’s study
supports this. They found that the anterior maxillary
14
height (measured from the palatal plane to the upper
incisor edge) showed a significant difference between the
gingival smile group and the reference group with a
difference of +2.3 mm (p <.001).3 In their study of
individuals with vertical maxillary excess, Schendel et al.
found that all persons in their VME sample, both with open
bite and without, showed excessive exposure of the
maxillary anterior teeth and poor upper lip to tooth
relationships in comparison to the norm.18 According to
Schendel et al., “extreme clockwise rotation, high angle
type, adenoid faces, idiopathic long face, total maxillary
alveolar hyperplasia, and vertical maxillary excess all
have excessive vertical growth of the maxilla as their
common denominator.”18 While many children and adults with
long faces also have vertical maxillary excess, Fields et
al. found that long faced children did not have a
significantly greater anterior dental height than normal
children, and while the adults had a tendency for excessive
eruption of all teeth, it was not statistically
significant.25 However, patients with long faces do have
some characteristic traits, such as increased mandibular
plane angles, increased palatal plane to mandibular plane
angles, increased ANB angles (and thus retrognathia), and
increased lower anterior face heights. Therefore, one
15
might conclude that persons with these characteristics
might also have the tendency for excessive gingival
display, although not to a predictive level. In a study by
McNamara et al, neither the vertical display on smile, nor
the amount of upper lip drape was correlated with the
skeletal vertical dimension,26 therefore it appears that
vertical maxillary excess is only one contributing factor
to a “gummy” smile.
In Schendel et al.’s study, the differences between
long faced, open bite and non open bite subjects were
investigated.18 They found that the open bite group had a
steeper mandibular plane angle, although both the open bite
and non open bite groups’ mandibular plane angles were
significantly greater than the norm. The occlusal plane
angle followed the same trend. The SNA was normal in both
groups, suggesting a normal anteroposterior position of the
maxilla in relation to the cranial base. However the SNB
was significantly decreased in both groups suggesting a
retrodisplacement of the mandible. Due to this
displacement, the ANB angle was also significantly
increased in both groups. Both the posterior height of the
maxilla and the anterior dental height were significantly
greater than normal. The largest vertical distance between
the two groups was the posterior facial height. The open
16
bite group had a normal ramal length while the non open
bite group exhibited a long ramal length.18 This suggests
that there was greater vertical growth of the ascending
ramus in the non open bite group that prevented the
development of an open bite. While Schendel and colleagues
found both groups to exhibit an increased amount of
maxillary display, it seems evident that orthodontic
treatment aimed to close the open bite via anterior
extrusion with or without posterior intrusion, would
exacerbate this problem.
The influence of skeletal disharmonies on the
production of a gingival smile line has been debated in the
literature. Singer cites SN-MP and SN-Pal as having
characteristic values associated with a gingival smile
line,19 however in Peck et al.’s study, the SN-MP and SN-PP
angles were not significantly different between the
gingival smile and reference groups.3 The study by Schendel
et al. would refute this finding, as they described all of
the VME sample to possess both an excess of gingival
display on smiling, and high mandibular plane angle’s as
well as an increased posterior height of the maxilla.18
A study by Fields et al. compared the differences in
long faced children and adults as compared to normal and
short faced children and adults. They found that long
17
faced, short faced, and normal children all have a similar
relationship of the maxilla to the cranial base. The long
and short-faced children had a tendency for a smaller SNB
angles, and therefore more retrognathic profiles than
normal children. The long-faced children had steep
mandibular plane angles while the short-faced children
displayed low mandibular plane angles. Measures of the
total anterior facial height were significantly different
between the groups, however there were no differences
evident in posterior total facial height. The differences
in the anterior facial height were found to lie within the
anterior lower face height, as the measures of the anterior
upper facial height were similar among the groups. Upon
further examination to determine the cause of this
difference, they found no difference in the size of the
ramus, but the gonial angles were significantly larger in
long-faced children and smaller in short-faced children.
Long-faced children had significantly greater posterior
maxillary and mandibular dental heights than normal
children. However, surprisingly there was not a significant
difference in the anterior upper dental height, although
the mean height was larger in the long faced children. As
would be expected, short faced children had significantly
18
less anterior upper and lower dental height than normal
children.25
Similar results were found for the adult groups with a
few important differences. Like the children, all groups
had similar cranial base configurations with well-related
maxillas, the long faced adults tended to be more
retrognathic, and the mandibular plane angles indicated
significant differences. The posterior total facial
heights and the anterior upper face heights were similar
for the groups, and the long faced adults had significantly
increased lower anterior facial heights. Similar to the
children, the long faced adults had normal mandibular body
lengths and increased gonial angles, but unlike the
children they had a tendency toward short rami and
excessive eruption of all teeth.25
Possible Causes of Gummy Smile Development During
Orthodontic Treatment
Unexpressed Vertical Growth
As Fields and colleagues asserts, “it is possible that
ramus differences are not apparent in children, since rapid
skeletal growth, and therefore, significant ramus
lengthening had not yet occurred in the preadolescent
sample.”25 This might indicate a cause for the skeletal
19
tendency to become gummy during the course of orthodontic
treatment. Because orthodontic treatment is often commenced
during early adolescence, the growth that occurs in long
faced individuals during this time (between childhood and
adulthood) appears to convert children with normal ramus
lengths and normal anterior dental heights to adults with
short mandibular ramus lengths and a tendency toward long
anterior dental heights. This decreased amount of growth of
the ramus, appears to affect the mandibular rotation, and
therefore produces a steeper mandibular plane angle.27
Schendel et. al. found short ramus heights in long faced
individuals with open bites, but long ramus heights in long
faced patients without open bites compared to the norm.
Those with short ramus heights and open bites also had much
much higher mandibular plane angles (SN-MP) on average
(48.61 degrees) than the non-open bite, long-faced
individuals with long ramal lengths (39.78 degrees).
However, both long faced groups had much greater mandibular
plane angles than the norm (31.75 degrees).18 This finding
agrees with the finding of Isaacson et al. who found
shorter ramus heights to be characteristic of patients with
steep mandibular plane angles.27
This lengthening in anterior dental heights (or
vertical maxillary excess) that appears to occur as long-
20
faced children grow into adulthood, would likely increase
the gingival display in these patients during growth even
without orthodontic treatment (as previously discussed).
Extrusive Forces
The tendency to develop a gingival smile might be
improved with careful orthodontic manipulation, however it
could easily be exacerbated if not diligently monitored, as
many of the forces used in orthodontic treatment are
extrusive. As Fields et al. points out, “although these
facial patterns are established early, events may occur
during adolescence to magnify or maintain the
differences.”25 Because the full effect of this growth
pattern is not yet evident during childhood, the prudent
orthodontist will recognize this pattern during diagnosis
of young patients, and discuss its tendency to produce
excessive gingival display with the patient and parents.
He/she should also include in his/her treatment steps to
control and not exacerbate this tendency.
In Isaacson et al.’s study of the extreme variations
in vertical facial growth, they state that the vertical
growth of the anterior face must be equal in size and
timing of the growth increases in the posterior face, or
the mandible will rotate at its articulation.27 According
21
to Isaacson et al., “if the vertical increases at the
facial sutures and/or the alveolar process should exceed
the vertical increases at the mandibular condyle, the
mandible would rotate backward. Conversely, if vertical
growth at the condyle should exceed the sum of the vertical
growth components at the facial sutures and alveolar
processes, the mandible would rotate forward.”27 According
to this study, if extrusive orthodontic forces cause
vertical growth of the alveolus faster than the condyle is
growing vertically, then the mandible could rotate backward
even in a patient without previous vertical growth.
Anterior-Posterior Position of the Maxilla
In their study, Isaacson et al. also found that as
the mandibular plane angle (SN-MP)decreased, the mean
values for SNA and SNB increased.27 The mean ANB angle
remained relatively constant. The measurements of linear
distance from a perpendicular to SN to the maxillary first
molar indicated that not only the skeletal components
increased in the horizontal dimension as the mandibular
plane angle decreased, but the dental components also
became more anteriorly situated.27 Therefore, Isaacson
concluded that the horizontal position of the maxilla
effects the mandibular plane angle. For this reason, a
22
person with a forward positioned maxilla and some vertical
maxillary excess could have a low mandibular plane angle,
and therefore, unless specifically measured, the maxillary
excess could perhaps be unapparent upon initial
examination. Persons presenting with a forward positioned
maxilla whether high or low angle, often have a Class II
skeletal and dental pattern. Orthodontic treatment aimed
at distalizing the maxilla, or maxillary dentition, to
correct the Class II dentition, according to Isaacson’s
study, would cause downward rotation of the mandible and an
increase in the mandibular plane angle, and would therefore
allow room for further increase in the height of the
maxilla both posteriorly and anteriorly. According to
Schendel and Field’s studies, this could cause an increased
tendency for gingival display.18,25
However, the literature tends to refute this point.
In Peck’s study, the gingival smile line group had greater
values for both overbite and overjet, by 1.5 mm and 1.0 mm
respectively.3 Therefore, it would seem that correcting the
overjet, might decrease the gingival smile. Accordingly,
Vig and Brundo found that individuals with moderate to
severe Class II malocclusions demonstrated an exceptional
resistance to the normal pattern of decreased maxillary
incisor show with age.16 Peck et al. suggest that
23
orthodontic correction of overjet may then improve a
gingival smile line in a Class II condition.3
Treatments For Gingival Smiles
As with any other orthodontic problem, the appropriate
treatment for a gingival smile is determined by the cause.
A gingival smile caused by short clinical crowns should be
treated with the appropriate gingival procedure, while a
gingival smile due to incorrect dental and skeletal
relationships should be treated orthodontically, or with a
combination of orthodontics and surgery. Other less
invasive procedures are also emerging to camouflage a
skeletal problem such as botox injections to decrease the
mobility of the upper lip and even anterior nasal spine
implants.
Treatments for Gingival Smiles Caused by Altered Passive
Eruption
As previously discussed, altered passive eruption
ia classified into two types, and the appropriate treatment
is determined by the type present. In Type I, there is an
excessive amount of gingiva from the free gingival margin
to the mucogingival junction. In Type II, there is a
normal amount of gingiva as measured from the free gingival
24
margin to the mucogingival junction. Type I is further
subdivided into sub-categories A and B depending on the
relationship of the osseous crest to the cemento-enamel
junction of the tooth. In subcategory A, the dimension
between the osseous crest and the CEJ is greater than 1 mm,
and therefore adequate for the insertion of the connective
tissue attachment component of the biologic width. In
subcategory B, the osseous crest is in close proximity to
the cementoenamel junction, therefore adequate space for
the connective tissue attachment component of the biologic
width.
Because there is adequate room for the connective tissue
attachment in Type IA, a simple gingivectemy procedure can
be performed to remove the excess gingiva. However,
because there is not adequate space for the connective
tissue attachment in Type IB, the connective tissue is
attached to the enamel. Therefore, without moving the
crestal bone apical to the cementoenamel junction to allow
adequate space for the connective tissue attachment to form
in its proper location, the connective tissue attachment
will reform on the enamel, and the gingival margin will
rebound. For this reason, gingivectemy procedures will be
unsuccessful, and a crown lengthening procedure to move the
25
crestal bone apically will be necessary to provide stable
results.20,21
In Type II altered passive eruption, the zone of
masticatory mucosa is not excessive, despite the clinically
evident short teeth. Treatment requires apical reduction
of the entire dentogingival complex with or without osseous
reduction to provide more ideal esthetics.20
Treatments for Gingival Smiles Caused by Incorrect Dental
and Skeletal Relationships
According to Proffit et al. “There are now three possible
approaches to excessive gingival exposure due to incorrect
dental and skeletal relationships: orthodontic intrusion,
orthognathic surgery to move the maxilla up, and implant
anchorage to intrude the maxillary teeth.28 The appropriate
treatment is determined by the etiology of the problem and
the age of the patient.
Orthodontic Intrusion
If the maxillary anterior teeth are excessively extruded
in relation to the posterior teeth and the bite is deep,
then the anterior teeth can be orthodontically intruded.
According to Garber and Salama, the entire attachment
apparatus, incorporating the bone, periodontal ligaments,
and the soft tissue moves together with the tooth,21 and
26
therefore intrusion should improve a gingival smile.
However, according to Waldrop, the ability of the
orthodontist to change gingival margin locations with tooth
movement may be affected by the facial-lingual thickness of
the attached gingival and bone.20
If the gingival smile is due to a true skeletal
Vertical Maxillary Excess (VME), then the posterior portion
of the maxilla will also be vertically overexpressed,
causing the mandible to rotate downward and backward. In
children, this growth pattern could possibly be modified
with careful attention to prevent all subsequent posterior
vertical growth of the maxilla, thus allowing the mandible
to rotate upward and forward if there is adequate vertical
ramus growth.29 This can be achieved with various approaches
including high-pull headgear to the maxillary molars, high-
pull headgear to a maxillary splint, a functional appliance
with bite blocks, and even a high-pull headgear to a
functional appliance with bite blocks for the the most
severe cases.29
Implant Intrusion
Until recently, intrusion of the maxillary anterior teeth
without the side effects of posterior extrusion was very
difficult. Extraoral force applications using the head as
anchorage (i.e., headgear) was the method of choice to
27
either directly intrude the anterior teeth (i.e., J-Hook
headgear), or to prevent the side effects of an anterior
intrusion arch (i.e. high pull headgear). However, the
unesthetic appearance of headgear decreased patient
compliance with full time wear and therefore decreased its
effectiveness. With the advent of orthodontic implants,
also known as temporary anchorage devices, effective
intrusion of anterior teeth has become possible. In a
recent study by Deguchi et. al., the effects of intrusion
of the maxillary incisors via implants was compared to the
effects produced with a J-Hook headgear. They found that
while both groups experienced significant reductions in
overjet, overbite, and maxillary incisor to upper lip,
there were significantly greater reductions in overbite,
maxillary incisor to palatal plane, and maxillary incisor
to upper lip in the implant group. A force analysis
indicated that the implant intrusion produced a
significantly greater force in the vertical direction and
less in the horizontal direction than the J-hook headgear
group.30 This study indicates that implant intrusion might
achieve more true intrusion without the undesired tipping
of the maxillary incisors that often occurs with
traditional intrusion mechanics. In a recent study by
Polat-Ozsoy et.al., similar findings were reported. They
28
found a mean intrusion of 2.25 mm with only small and
insignificant changes in the U1 to NA and U1 to Palatal
plane angles, 1.22 and 1.81 mm respectively.31 Not only do
orthodontic implants appear to achieve more true intrusion
without the undesired side effects, but according to a
study by Scheffler at the University of North Carolina in
2005 (cited by Proffit et. al.) patients prefer implants to
headgear and reported minimal pain from implant placement.28
Other recent case reports have also demonstrated successful
treatment of patients with deep overbites and “gummy”
smiles with the use of orthodontic implants for maxillary
incisor intrusion.32,33
Orthognathic Surgery
In adults, growth modification is no longer an option.
Therefore, intrusion of the anterior teeth in the absence
of a deep bite would, at the very least, create a reverse
smile arc, and possibly result in an anterior open bite.
Therefore, orthognathic surgery to impact the maxilla is
the only true corrective treatment option. However, as
Garber et. al. points out, proper diagnosis of the severity
of the vertical maxillary excess present involves ruling
out the superimposition of altered passive eruption in
combination with maxillary hyperplasia. They state, if
altered passive eruption is present, it should be treated
29
first to develop a normal tooth form before a final
treatment plan is determined.21 Only then can the true
severity of the hyperplasia be assessed. In some cases, the
translation of the upper lip from rest to maximum smile is
greater the normal length of a tooth crown. In such a
case, the patient must determine if some gingival display
will be tolerated, or if a increased length of the crowns
of the maxillary incisors is preferred. This will prevent
overimpaction of the maxilla, which results in burying of
the incisal edge beyond the vermillion border of the lip
resulting in a dramatically aged appearance. For this
reason, it is critical to treat to the position of the lip
at rest. A minimum of 2 mm of the incisal edge of the
maxillary incisors should be displayed at rest.21 Peck
points to surgical repositioning of the maxilla to reduce
vertical maxillary excess as the most effective treatment
modality. However, he notes that this procedure has
limitations due to the lip shortening that occurs with
skeletal intrusion (50% of the skeletal intrusion).3
Treatments for Gingival Smiles Caused by Hyperfunction of
the Lip Elevator Muscles
Due to the invasiveness and cost of maxillary
osteotomy surgery, other methods of correcting a “gummy”
30
smile have emerged. In Peck et al.’s study, the gingival
smile group raised the upper lip higher than average during
smiling.3 This hyperfunction of the lip elevator muscles is
thought to contribute to the production of a gummy smile.
Therefore, several soft tissue surgical procedures have
been reported to correct a gummy smile caused by
hyperfunction. These methods include severing the muscular
attachments, botulinum toxin, and even an anterior nasal
spine implant.
Muscle Resection
Polo, Rubinstein and Kostianovsky describe a procedure
in which a portion of the gingival and buccal mucosa is
resected and the borders approximated and sutured.34 Litton
and Fournier describe a procedure to detach the elevator
muscles from the maxilla,35 while Miskinyar describes a
technique in which he performs a myectomy and partial
amputation of the levator labii superioris muscles.36
However, Ellenbogen reports that resection of the levator
labii superioris is short lived, and the gummy smile
returns within six months.37 He suggests placing either a
nasal cartilage or prosthetic material as a spacer to
prevent this reunion of the muscle fibers and reoccurrence
of the gummy smile.37 Miskinyar reported good results with
this technique at 8 year follow ups, but points out
31
possible disadvantages including migration of the spacer to
a foreign site, foreign body reaction if a prosthetic
implant is used, and the need for a second surgical
procedure if nasal cartilage is used.38 Rees and LaTrenta
describe a camouflage procedure for long faced syndrome
patients in which subperiosteal dissection of the lip
elevators is performed,39 and Ezquerra et al. describe a
multidisciplinary approach that incorporates lefort
osteotomies, with gingival remodeling, and the procedure
described by Rees and LaTrenta.40
Botulinum Toxin
Although less invasive than an osteotomy, surgical
procedures to resect the lip elevator muscles require
incisions with the possibility of scarring and variable
long-term results. Therefore, botulinum toxin has been
investigated as a non-surgical alternative for reducing
gingival display caused by muscular hyperfunction. In a
recent study by Mario Polo,41 twelve women with excessive
gingival display were injected at two sites with 1.25 U of
botulinum toxin in the right and left levator labii
superioris alaeque nasi muscles, and the overlap areas of
the levator labii superioris and zygomaticus minor muscles.
These injection were repeated in a second phase of the
study one month later and followed by a 2.5 U injection in
32
a third phase. Those that had the greatest amount of
elevation near the philthrum also received injections at
the origin of the depressor septi nasi muscle at the
orbicularis oris muscle at each phase of the study. He
found that all patients demonstrated improvement 10 days
post-injection, while the maximum effect was observed 14
days post-injection with a mean decrease in gingival
display of 4.2 mm. This effect was reversible, lasting for
3 to 6 months. He reports that all patients were pleased
with the results and no side effects were reported or
observed.41 In a letter to the editor in response to Polo’s
article, Niamtu, relates experiences of unesthetic perioral
animation in his patients treated with botulium toxin
injections. He states, “they looked dysfunctional,”
described a “range from slight change in smile, pucker, and
word pronunciation to a “stroke like” expression in some
phases of animation.” He suggests that the photos in
Polo’s study cannot truly display the appearance of the
patients in animation. While he relates years of
experience with botox, he warns that dramatic undesirable
results can be produced by inexperienced practitioners
including severe drooling, inability to pucker, grossly
asymmetric smiles, inability to annunciate words, and a
stroke like appearance.42
33
In a follow up study by Polo to determine whether the
dose and injection sites used in the pilot study produce
consistent, esthetically pleasing results, Polo injected 30
patients with 2.5 U at the same sites as discussed in his
pilot study and followed them at 2,4,8,12,16,20 and 24
weeks post-injection with changes documented by photographs
and videos. Again the maximum effect was observed at 2
weeks post-injection with a mean decrease in gingival
display of 5.1 mm. The gingival display increased
gradually, although the gingival display had not yet
returned to baseline by week 24. It was estimated with a
polynomial equation that the pre-treatment gingival display
would not be reached until 30 to 32 weeks post-injection.
At week 2, patients and a panel of specialty evaluators
rated the effects of the botox injections via pre and post
treatment photographs and videos on a 1 to 5 point scale
with 1 representing poor and 5 representing excellent.
Both patients and specialists rated the results between
very good and excellent with a mean of 4.66 and 4.65
respectively.43 In a recent study by Hwang et. al., the
distribution, morphology, and direction of muscles fibers
of the levator labi superioris (LLS), the levator labii
superioris alaeque nasi (LLSAN), and the zygomaticus minor
(ZMi)and major(ZMj) muscles were investigated on 25 adult
34
cadavers with the aim of proposing a safe and reproducible
injection point for botulinum toxin type A. They found
that the three lip elevator muscles converged on the area
lateral to the ala of the nose with no significant
differences in the angular projection of the muscle fibers
from origin to insertion between males and females or left
side to right side. This area of convergence was prosposed
as a safe and reproducible injection site for the botulinum
toxin. Injection at this site was demonstrated to be
clinically effective in the reduction of a gingival smile
due to muscular hyperfunction in two cases. In summary,
while still in its early stages, research indicates that
botulium toxin type A might be an effective, yet transient
treatment for excessive gingival display.
Anterior Nasal Spine Implants
In addition to surgical resection of the elevator muscles
and botulinium toxin to reduce the activity of the muscles,
the use of an anterior nasal spine implant has been
reported to mechanically obstruct the lip from raising and
thus reduce the amount of gingiva displayed upon smiling.
Austin describes a technique in which a pouch is created by
elevating the periosteum from the anterior nasal spine and
adjacent maxilla for 10 mm on each side. It is then filled
with a silicone implant material, which is allowed to
35
harden and conform to shape of the area. It is then
removed, trimmed to prevent protuberant edges and then
reimplanted into the pouch and the pocket is sutured. He
reports excellent results and pleased patients with a mean
follow up of three years. He reports only one infection
requiring removal of the implant and suggests both IV and
local antibiotics to prevent this complication.44
Summary and Statement of Thesis
The literature indicates that the “ideal” smile as
determined by the general public displays very little
gingiva upon smiling, and due to the increasing esthetic
demands of the public, orthodontists are taxed to produce
the “ideal.” Therefore, not only is the knowledge to treat
patients that present with “gummy” smiles necessary, but
more important is the knowledge to recognize those that
have a tendency to become “gummy,” and to prevent the
development of a “gummy” smile during orthodontic
treatment.
The purpose of this study is to compare the pre and
post treatment cephalometric radiographs of patients who
obtain a great increase in gingival display during
treatment to those that obtain a great decrease, as well as
those that obtain the average change in gingival display.
36
It is our hope that this comparison will identify the pre-
treatment skeletal, dental, and soft tissue characteristics
that indicate a tendency to obtain an increase or decrease
in gingival display during treatment and/or the skeletal,
dental, and soft tissue changes that occur to produce this
change in lip drape.
37
References
1. Ker AJ, Chan R, Fields HW, Beck M, Rosenstiel S.
Esthetics and smile characteristics from the layperson's
perspective: a computer-based survey study. J Am Dent
Assoc. 2008;139(10):1318-1327.
2. Van der Geld P, Oosterveld P, Van Heck G, Kuijpers-
Jagtman AM. Smile attractiveness. Self-perception and
influence on personality. Angle Orthod. 2007;77(5):759-
765.
3. Peck S, Peck L, Kataja M. The gingival smile line. Angle
Orthod. 1992;62(2):91-100.
4. Mackley RJ. An Evaluation of smiles before and after
orthodontic treatment. Angle Orthod. 1993;63(3):
183-189.
5. Hulsey CM. An esthetic evaluation of lip-teeth
relationships present in the smile. Am J
Orthod. Dentofacial Orthop. 1970;57(2):132-144.
6. Matthews TG. The anatomy of a smile. J Prosthet Dent.
1978;39(2):128-134.
7. Carnegie D. How To Win Friends and Influence People..
Simon and Schuster; 1936.
8. Tjan AH, Miller GD, The JG. Some esthetic factors in a
smile. J Prosthet Dent. 1984;51(1):24-28.
9. Peck S, Peck L, Kataja M. The gingival smile line. Angle
Orthod. 1992;62(2):91-100; discussion 101-102.
10. Kokich VO, Kiyak HA, Shapiro PA. Comparing the
perception of dentists and lay people to altered dental
esthetics. J Esthet Dent. 1999;11(6):311-324.
11. Chiche GJ, Pinault A. Smile rejuvenation: a methodic
approach. Pract Periodontics Aesthet Dent.
1993;5(3):37-44; quiz 44.
38
12. Geron S, Atalia W. Influence of sex on the perception
of oral and smile esthetics with different gingival
display and incisal plane inclination. Angle Orthod.
2005;75(5):778-784.
13. Hunt O, Johnston C, Hepper P, Burden D, Stevenson M.
The influence of maxillary gingival exposure on dental
attractiveness ratings. Eur J Orthod. 2002;24(2):199-
204.
14. Gul-e-Erum, Fida M. Changes in smile parameters as
perceived by orthodontists, dentists, artists, and
laypeople. World J Orthod. 2008;9(2):132-140.
15. Peck S, Peck L, Kataja M. Some vertical lineaments of
lip position. Am J Orthod. Dentofacial Orthop.
1992;101(6):519-524.
16. Vig RG, Brundo GC. The kinetics of anterior tooth
display. J Prosthet Dent. 1978;39(5):502-504.
17. Van der Geld PA, van Waas MA. [The smile line, a
literature search]. Ned Tijdschr Tandheelkd.
2003;110(9):350-354.
18. Schendel SA, Eisenfeld J, Bell WH, Epker BN,
Mishelevich DJ. The long face syndrome: vertical
maxillary excess. Am J Orthod. Dentofacial Orthop.
1976;70(4):398-408.
19. Singer R. A study of the morphologic, treatment and
esthetic aspects of gingival display. Am J Orthod.
Dentofacial Orthop. 1974;65:435-436.
20. Waldrop TC. Gummy Smiles: The Challenge of Gingival
Excess: Prevalence and Guidelines for Clinical
Management. Seminars in Orthodontics. 2008;14(4):260-
271.
21. Garber DA, Salama MA. The aesthetic smile: diagnosis
and treatment. Periodontol. 2000. 1996;11:18-28.
22. Volchansky A, Cleaton-Jones P. Delayed passive
eruption-a predisposing factor to Vincent's infection.
J Dent Assoc S Afr. 1974;29:291-294.
39
23. Konikoff BM, Johnson DC, Schenkein HA, Kwatra N,
Waldrop TC. Clinical crown length of the maxillary
anterior teeth preorthodontics and postorthodontics. J.
Periodontol. 2007;78(4):645-653.
24. Willmar K. On Le Fort I osteotomy; A follow-up study of
106 operated patients with maxillo-facial deformity.
Scand J Plast Reconstr Surg. 1974;12(0):suppl 12:1-68.
25. Fields HW, Proffit WR, Nixon WL, Phillips C, Stanek E.
Facial pattern differences in long-faced children and
adults. Am J Orthod. 1984;85(3):217-223.
26. McNamara L, McNamara JA, Ackerman MB, Baccetti T. Hard-
and soft-tissue contributions to the esthetics of the
posed smile in growing patients seeking orthodontic
treatment. Am J Orthod Dentofacial Orthop.
2008;133(4):491-499.
27. Isaacson JR, Isaacson RJ, Speidel TM, Worms FW. Extreme
variation in vertical facial growth and associated
variation in skeletal and dental relations. Angle
Orthod. 1971;41(3):219-229.
28. Proffit WR, Fields HW, Sarver DM. Chapter 8:
Orthodontic Treatment Planning: Limitations,
controversies, and Special Problems. In: Contemporary
Orthodontics. fourth. St. Louis, Missouri: Mosby, Inc.;
2007.
29. Fields HW, Proffit WR. Chapter 13: Treatment of
Skeletal Problems in Children. In: Contemporary
Orthodontics. fourth. St. Louis, Missouri: Mosby, Inc.;
2007.
30. Deguchi T, Murakami T, Kuroda S, et al. Comparison of
the intrusion effects on the maxillary incisors between
implant anchorage and J-hook headgear. Am J Orthod
Dentofacial Orthop. 2008;133(5):654-660.
31. Polat-Ozsoy O, Arman-Ozcirpici A, Veziroglu F.
Miniscrews for upper incisor intrusion. Eur J Orthod.
2009;31(4):412-416.
32. Ohnishi H, Yagi T, Yasuda Y, Takada K. A mini-implant
for orthodontic anchorage in a deep overbite case.
Angle Orthod. 2005;75(3):444-452.
40
33. Kim T, Kim H, Lee S. Correction of deep overbite and
gummy smile by using a mini-implant with a segmented
wire in a growing Class II Division 2 patient. Am J
Orthod Dentofacial Orthop. 2006;130(5):676-685.
34. Rubinstein A, Kostianovsky A. Cosmetic surgery for the
malformation of the laugh: original technique. Prensa
Med Argent. (60):952.
35. Litton C, Fournier P. Simple surgical correction of the
gummy smile. Plast. Reconstr. Surg. 1979;63(3):372-373.
36. Miskinyar SA. A new method for correcting a gummy
smile. Plast. Reconstr. Surg. 1983;72(3):397-400.
37. Ellenbogen R. Correspondence and brief communications.
Plast. Reconstr. Surg. (73):697-98.
38. Miskinyar S. Correspondence and brief communications.
Plast. Reconstr. Surg. (73):697.
39. Rees T, LaTrenta G. The long face syndrome and
rhinoplasty. Persp Plast Surg. (3):116.
40. Ezquerra F, Berrazueta MJ, Ruiz-Capillas A, Arregui JS.
New approach to the gummy smile. Plast. Reconstr. Surg.
1999;104(4):1143-1150; discussion 1151-1152.
41. Polo M. Botulinum toxin type A in the treatment of
excessive gingival display. Am J Orthod Dentofacial
Orthop. 2005;127(2):214-218; quiz 261.
42. Niamtu III J. Letters to the editor: Botox injections
for gummy smiles. Am J Orthod Dentofacial Orthop.
2008;133:782-3.
43. Polo M. Botulinum toxin type A (Botox) for the
neuromuscular correction of excessive gingival display
on smiling (gummy smile). Am J Orthod Dentofacial
Orthop. 2008;133(2):195-203.
44. Austin HW. Correction of the gummy smile--a plastic
surgeon's view. Dent Today. 1990;9(2):28.
41
CHAPTER 3: JOURNAL ARTICLE
Abstract
Objective: The purpose of this study is to determine
which dental, skeletal, and soft tissue characteristics
affect lip height and which characteristics affect lip
height changes during treatment. Materials and Methods:
Models for 200 randomly selected subjects were obtained and
used to calibrate the smiling photographs of each subject.
The photographs were then measured to determine the change
in gingival display that occurred during treatment. The
change in gingival display was used to create three groups:
those that obtained the greatest increase, greatest
decrease, and average change in gingival display. The
cephalometric radiographs were then traced for each subject
and digitized. The pre and post treatment cephalometric
radiographs of each subject were superimposed and a total
of 54 linear measures were made at each time point. The
measures were then compared using t-tests for intra-group
changes from T1 to T2 and an Analysis of Variance (ANOVA)
for inter-group comparisons at each time point.
Results: There were no significant differences between the
groups at the pretreatment time point. Paired t tests
revealed significant differences in 25 of the 27 vertical
42
measures within all groups from the pre treatment to post-
treatment time points. The horizontal measures indicated
more significant differences in the backward direction in
the greatest increase group than the other two groups. The
significant vertical difference between the groups at the
post-treatment time point was found between the average
change group and the greatest increase group at condylion.
The significant horizontal differences between the groups
were found between the greatest increase and greatest
decrease groups at the soft tissue lips. The lips moved
significantly backward in the greatest increase group while
they stayed relatively the same in the greatest decrease
group.
Conclusions: No pretreatment characteristic could be
identified to predict the tendency to experience an
increase or decrease in gingival display during orthodontic
treatment. The lips moved significantly backward in the
group that experienced an increase in gingival display
while they stayed relatively the same in the group that
experienced a decrease. Although not significant, other
general tendencies were apparent between the two extreme
groups. Further research is warranted.
43
Introduction
!
!
As society becomes more esthetically conscious,
orthodontists are becoming challenged to produce not only
outstanding occlusions, but also outstanding esthetics.
Every minute detail is becoming more important in
separating the good from the great treatment result.
Recent studies have indicated that the public at large
believes that the amount of gingival display on smiling is
very important to attractiveness.1 In fact, Van der Geld et
al. found that the amount of gingival display is an
important characteristic in a person’s own satisfaction
with their smile.2
When an excessive amount of gingiva is displayed upon
smiling, the term “gummy” is often used. While many
clinicians anecdotally point to the “lack of vertical
control” as the cause of orthodontically produced
“gumminess,” few studies that investigate the cause of post
treatment gummy smiles are present in the literature. Peck
et al. found that the tendency of a person to project a
gummy smile was related to anterior vertical maxillary
excess, the muscular ability to raise the upper lip higher
than average when smiling, greater overjet, greater
interlabial gap at rest, and greater overbite.3 This study,
44
as well as many others, have found that females have a
predilection to display more gingiva while smiling than
their male counterparts.3456
Lip length has also been suspect to affect gingival
display, however, the literature refutes this assertion.3,7
In fact, Singer reported that his gingival smile group had
a significantly longer lip length than his non-gingival
display group.8 Altered passive eruption has also been
suggested to produce short clinical crown heights and
therefore increase the tendency to produce a gingival
smile. However, in Peck et al.’s study, the clinical crown
height of the gingival display group was not significantly
different.3
In Mackley’s study to determine the effectiveness of
improving patient smiles with orthodontic treatment and the
variability of improvement from orthodontist to
orthodontist, he found that the orthodontist who was most
successful in producing greater post treatment smile
improvement scores decreased the stomion-incision
measurement, while those that increased the stomion-
incision measure produced smiles with lower post treatment
improvement scores. He states, “This measurement is an
indication of the amount of gingival tissue that shows when
a person is smiling.” He also suggested that the most
45
successful orthodontist also increased the inclination of
the maxillary incisor to the Nasion-A Point line, while
those that produced less improvement decreased this
measure. He concludes that in order to “maximize our
potential for improving the smile, we must include in our
treatment plan an objective for moving the anterior teeth
vertically to improve their relationship to the smiling lip
line.”9
While these studies indicate possible reasons for an
increase in gingival display, none indicate any pre-
treatment skeletal or dental factors that might help a
clinician to predict the development of this “gumminess”
during orthodontic treatment nor investigates post-
treatment skeletal and soft tissue factors that might
produce this negative condition. The purpose of this study
is to determine which dental, skeletal, and soft tissue
characteristics affect smiling lip height and which
characteristics affect lip height changes during
orthodontic treatment.
46
Materials and Methods
Sample
A sample of 200 subjects (114 Females and 86 Males)
was randomly selected from the archives of records at Saint
Louis University Center for Advanced Dental Education.
Only patients who began treatment between the ages of 10
and 14 years of age, and had pre and post treatment
photographs, models, and lateral cephalometric radiographs
were included. A consistent head position and extent of
smile in the pre and post-treatment photos were also
required in order to be included in the study.
Sample Selection
The database of records at the Center for Advanced
Dental Education at Saint Louis University was reviewed
beginning with the first letter of the alphabet. The first
200 patients that met the inclusion criteria were included
in the study. Once the records were obtained, the width of
the maxillary left central incisor was measured to the
nearest tenth of a millimeter using a digital caliper on
the stone model and recorded. This measure was then used
to calibrate the smiling photograph of the patient using
the Dolphin Imaging photo calibration tool. Once photo
calibration was completed, the length of the maxillary left
47
central incisor was measured on the stone model and
recorded. For this purpose, the length of the maxillary
left central incisor was defined as the distance between
the incisal edge and the most superior point on the
gingival margin. The distance between the incisal edge of
the maxillary left central incisor and the most incisal
portion of the upper lip was then recorded. The amount of
gingival display was recorded as the difference between the
length of the maxillary left central incisor and the
distance between the maxillary left central incisal edge
and the most inferior portion of the upper lip (Figure
3.1). Therefore, patients with visible gingival exposure
upon smiling would have a positive number of gingival
display and patients with lip coverage of their maxillary
incisors upon smiling would have a negative number recorded
(Figure 3.2).
Figure 3.1 Calculation of Gingival Display. The gingival exposure was calculated as the
difference between 1 and 2 minus the difference between 1 and 3. i.e. (1-2)-(1-3).
(Modified from Van der Geld et. al.)2
48
Figure 3.2 Description of Measures of Gingival
Display. A positive measure was given for any gingiva
visible above the maxillary left central incisor while any
incisor coverage was given a negative measure (Modified
from Peck and Peck)3
After the amount of gingiva displayed upon smiling was
determined for the pre and post treatment time points (T1
and T2) for each patient, the change from T1 to T2 was
determined and recorded to the nearest tenth of a
millimeter. The change in gingival exposure for the 200
patients was analyzed using the SPSS program and the mean
and median values were determined. The mean change in
gingival exposure for the 200 patients was 0.7349 mm while
the median change was 0.660 mm suggesting that a homogenous
sample of normally distributed patients was obtained (see
table 3.1).
49
Mean Change 0.7349 mm
Median Change 0.660 mm
Standard
Deviation
1.96581 mm
Range 13.87 mm
Minimum -6.92 mm
Maximum 6.95 mm
The sample was then divided into three groups: Group
1. those that obtained the greatest decrease in gingival
exposure during treatment; Group 2. those that had the
average amount of change during treatment; Group 3. those
that obtained the greatest increase in gingival exposure;
The groups were developed by taking one standard deviation
from the median. Those that obtained a minimum of one
standard deviation less than the median change during
orthodontic treatment were included in the “greatest
decrease” group or Group 1. The 15 patients on each side of
the median made up the “average change” group or Group 2.
Those that obtained a minimum of one standard deviation
greater than the median change during treatment were
included into the “greatest increase” group or Group 3.
Table 3.1 Descriptive Statistics for the change in
gingival display of the 200 subjects
50
Group 1 contained 21 subjects (8 females and 13 males)
and had a mean change of -2.55 mm. Group 2 contained 29
subjects (17 Females and 12 Males) (one was thrown out due
to a magnification differential) and had a mean change of
0.65 mm, and group 3 contained 33 subjects (20 females and
13 males) and had a mean change of 3.75 mm (see table 3.2).
Table 3.2: Description of Sample Groups
Group Number
of
Subjects
Mean Change
in Gingival
Display (mm)
Gender
Differences
Molar
Classifications
1
(Greatest
Decrease
in
Gingival
Display)
21 -2.55 8 Females
13 Males
8 Class I
9 Class II
4 Class III
2
(Average
Change in
Gingival
Display)
29 0.65 17 Females
12 Males
21 Class I
5 Class II
3 Class III
3
(Greatest
Increase
in
Gingival
Display)
33 3.75 20 Females
13 Males
19 Class I
11 Class II
3 Class III
51
Data Collection
The pre and post treatment cephalometric radiographs
of the three groups (83 subjects) were hand traced and 28
soft and hard tissue landmarks were identified(See table
3.3 and figure 3.3).
Table 3.3 Landmark abbreviations and descriptions
Landmark Abbreviation Description
Sella S Midpoint of the cavity of the
pituitary fossa of the sphenoid
bone
Nasion N Junction of the frontonasal
suture at the most posterior
point on the curve at the bridge
of the nose
Anterior Nasal
Spine
ANS Tip of the median, sharp bony
process of the maxilla at the
lower margin of the anterior
nasal opening
Posterior Nasal
Spine
PNS The most posterior point at the
sagittal plane on the bony hard
palate
Point A or
Subspinale
A pt The most posterior point on the
curve of the maxilla between the
anterior nasal spine and
supradentale
Point B or
Supramentale
B pt The point most posterior to a
line from infradentale to
pogonion on the anterior surface
of the symphyseal outline of the
mandible
Pogonion Pog Most anterior point on the
contour of the bony chin
Gnathion Gn Most inferior and anterior point
on the contour of the bony chin
Menton Me Most inferior point on the
symphyseal outline
Gonion
Go
Midpoint of the angle of the
mandible
Condylion Co Most posterior superior point on
the curvature of the average of
the right and left outlines of
the condylar head
Pronasale Prn Most anterior point on the tip
of the nose
Subnasale Sn The point at which the nasal
septum mergest, in the
midsagittal plane, with the
upper lip
52
Table 3.3 (Continued)
Landmark Abbreviation Description
Labrale Superius Ls Most anterior point of the upper
lip
Stomion Superius Ss Most inferior point of the upper
lip
Stomion Inferius Si Most superior point of the lower
lip
Labrale Inferius Li Most anterior point of the lower
lip
Soft Tissue
Pogonion
Pg’ Most anterior point of the soft
tissue chin
Maxillary Incisor
Apex
U1a
The root tip of the maxillary
central incisor
Maxillary Incisor
Incisal Edge
U1i
The incisal tip of the maxillary
central incisor
Mandibular Incisor
Apex
L1a The root tip of the mandibular
central incisor
Mandibular Incisor
Incisal Edge
L1i The incisal tip of the
mandibular central incisor
Maxillary First
Molar Apex
U6a The root tip of the most
anterior root of the maxillary
first molar
Maxillary First
Molar Mesial Cusp
Tip
U6c The anterior cusp tip of the
maxillary first molar
Mandibular First
Molar Apex
L6a The root tip of the most
anterior root of the mandibular
first molar
Mandibular First
Molar Mesial Cusp
Tip
L6c The anterior cusp tip of the
mandibular first molar
Posterior
Functional Occlusal
Plane
PFOP The plane that intersects the
biting surfaces of the posterior
teeth; measured from the distal
cusp of the maxillary first
molar
Anterior Functional
Occlusal Plane
AFOP A point formed by a
perpendicular from the tip of
the maxillary central incisor to
the plane that intersects the
biting surfaces of the posterior
teeth
53
Figure 3.3 Cephalometric Landmarks
!
54
After the cephalometric radiographs were traced, they
were digitized, using a Numonic Digitizing Table (model #
IPS/BL.E-A30BL.H). Dentofacial Planner 7.0 software was
used to translate each landmark into x-y coordinates. The
pre and post treatment cephalometric radiographs of each
subject were superimposed on the anterior cranial base
(best fit on the planum sphenoid, cribiform plate, greater
wings of sphenoid) and registered on sella.
Two reference planes were then generated to assist
with the cephalometric analysis. A horizontal reference
plane was drawn at the level of the sella-nasion line minus
7 degrees (SN-7°). A vertical reference plane (SN-7°-
perpendicular) was then drawn through sella, perpendicular
to the SN-7° line (see Figure 3.4).!
!
!
!
!
!
!
!
!
!
!
55
!
!
!
!
!
!
!
!
!
!
!
!
!
Figure 3.4 Reference Planes
A total of 54 linear measures were made on each
cephalometric radiograph at each time point (27 vertical
and 27 horizontal) by dropping lines perpendicular to the
SN-7 reference plane or SN-7 perpendicular respectively.
See Figures 3.5 and 3.6.
56
Figure 3.5 Examples of and vertical measures from the SN-7 the
reference plane
Figure 3.6 Examples of Horizontal Measures from the SN-7 Perpendicular
reference plane
57
Data Analysis
Due to the lack of literature available, all 27
variables were studied to determine which variables are
important in gingival display. In order to maintain the
power of the analysis, the variables were divided into four
groups: soft tissue, maxilla, mandible, and dental.
Paired t tests were used to compare the horizontal and
vertical measures within each group at the T1 and T2 time
points. An Analysis of Variance was (ANOVA) then used to
compare both the horizontal and vertical measures between
each analysis group at each time point (T1 and T2).
Because the sample sizes were not equal, the significant
measures were compared using Tukey’s Post Hoc and a mean
sample size of 26 was used.
All statistical computations were calculated by means
of standard computer software (SPSS for Windows, release
15.0.0, Inc., Chicago, IL). Statistical significance was
set at P<.05.
Analysis of Error
Due to the potential for human error inherent to the
process of landmark identification and tracing
cephalometric radiographs, as well as the process of
measuring gingival display using a digital caliper on
58
models and photo calibration, 10% of each of the samples
was randomly selected for measurement duplication. Twenty
subjects were re-measured for reliability of the gingival
measures (200 in initial sample), and 9 subjects were
remeasured for cephalometric analysis (83 subjects in
cephalometric study). All measures were repeated for the
cephalometric radiographs, models, and photos.
A reliability analysis (intercorrelation coefficient)
was performed comparing the initial to the repeated
measures. The reliability coefficient was found to range
from 0.995 to 0.999 for the gingival measures and to range
from 0.994 to 1.000 for the cephalometric measures.!
!
Results
The first set of inferential statistics tested for
significant differences between each of the groups at the
pre-treatment time point. The Analysis of Variance revealed
no significant differences between any of the groups for
any of the 27 landmarks in either the horizontal or the
vertical dimensions at the pretreatment time point (see
appendix A Tables A.1–A.16). Therefore, all significant
differences found at the post treatment time point can be
attributed to change that occurred during treatment.
59
Paired t tests were used to investigate significant
differences between the T1 and T2 time points within each
of the groups. They revealed significant differences in 25
of the 27 vertical measures for all three groups from the
pre treatment to post-treatment time points, as would be
expected in a growing sample. The non-significant variables
included nasion, which was included in the reference plane,
and condylion. The horizontal measures showed more
variability. The following horizontal measures were found
to be significant between the T1 and T2 time points for
group 1: pronasale, subnasale, menton, and gonion (Table
3.4). Significant horizontal measures from T1 to T2 for
group 2 include: pronasale, A point, B point, Gnathion,
menton, gonion, and L-6 Apex (Table 3.5). All horizontal
measures were significant between the T1 and T2 time points
for group 3 with the exception of nasion, pronasale,
subnasale, Posterior functional occlusal plane, Lower 6
tip, and Lower 6 apex (Table 3.6)
The following horizontal measures were found to be
significantly different at the post-treatment time point
between group 1 and group 3: Labrale superius, Stomion
superius, Stomion inferius, and Labrale inferius (tables
3.7-3.9). The non-significant measures at the post-
treatment time point appear in Appendix B (tables B.1-
60
B.16). No significant differences were found in the
horizontal measures between any of the groups (see Appendix
B Tables B.1,B.2, B.5, B.6, B.9, B.10, B.13, B.14), however
some tendencies are apparent when the groups are compared
at each time point (see Tables: 3.13-3.20). The only
significant vertical measure at the post treatment time
point was found between group 2 and group 3 at the
condylion measure (tables 3.10-3.12). No other significant
differences were found in the vertical measures at the post
treatment time point (see Appendix B Tables B.3, B.4, B.7,
B.8, B.11, B.12, B.15, B.16), however as with the
horizontal, some tendencies are easily seen when the groups
are compared (see Tables 3.13 -3.20).
61
Table 3.4 Group 1 Pre-treatment Vs. Post-treatment
Variable T1 T2 !T2-T1 Sig
V Nasion -8.9381 -8.9571 -0.019 0.162
H Nasion 72.8571 72.9571 0.1 0.241
V Pronasale 37.4381 44.1048 6.6667 ***0
H Pronasale 99.1286 102.481 3.3524
**
0.001
V Subnasale 50.5952 56.0238 5.4286 ***0
H Subnasale 85.7286 87.0762 1.3476
*0.031
V Labrale
Superius 64.6952 70.619 5.9238 ***0
H Labrale
Superius 90.4857 90.8762 0.3905 0.601
V Stomion
Superius 73.4619 79.6762 6.2143 ***0
H Stomion
Superius 82.919 82.5524 -0.3666 0.731
V Stomion
Inferius 74.6619 80.6 5.9381 ***0
H Stomion
Inferius 82.2238 82.3143 0.0905 0.94
V Labrale
Inferius 82.6143 89.6571 7.0428 ***0
H Labrale
Inferius 86.3 86.7619 0.4619 0.686
V Pogion' 106.2333 114.019 7.7857 ***0
H Pogion' 75.0667 75.3333 0.2666 0.823
V ANS 46.5048 50.6619 4.1571 ***0
H ANS 70.7095 69.8714 -0.8381 0.26
V PNS 44.3952 47.6619 3.2667 ***0
H PNS 18.2857 16.9762 -1.3095 0.118
V A Point 49.4667 54.3952 4.9285 ***0
H A Point 68.5048 67.5667 -0.9381 0.139
V B Point 94.6571 101.0381 6.381 ***0
H B Point 61.9048 61.3286 -0.5762 0.498
V Pogonion 107.0714 116.8333 9.7619 ***0
H Pogonion 61.3857 59.881 -1.5047 0.211
V Gnathion 111.2476 120.581 9.3334 ***0
H Gnathion 58.6762 56.4238 -2.2524 0.092
V Menton 112.3762 121.3429 8.9667 ***0
H Menton 54.7905 51.8095 -2.981 *0.046
V Gonion 74.1714 78.6714 4.5 **0.001
62
Table 3.4 (Continued)
Variable T1 T2 !T2-T1 Sig
H Gonion -11.419 -15.119 -3.7 **0.002
V Condylion 23.4714 22.781 -0.6904 0.534
H Condylion -19.6095 -20.8905 -1.281 0.078
V Post FOP 66.1714 71.7381 5.5667 ***0
H Post FOP 31.9143 32.1667 0.2524 0.775
V Ant FOP 76.819 82.1524 5.3334 ***0
H Ant FOP 74.5857 73.319 -1.2667 0.253
V U6 Apex 48.119 53.5 5.381 ***0
H U6 Apex 45.1 44.9905 -0.1095 0.896
V L6 Apex 89.0095 95.4857 6.4762 ***0
H L6 Apex 33.2524 34.0571 0.8047 0.389
V L6 Tip 68.2619 74.9143 6.6524 ***0
H L6 Tip 41.8 43.3143 1.5143 0.089
V U1 Tip 76.5048 81.8476 5.3428 ***0
H U1 Tip 74.6905 73.2381 -1.4524 0.203
V U1 Apex 49.2714 55.3381 6.0667 ***0
H U1 Apex 62.5905 62.4286 -0.1619 0.806
V L1 Tip 72.8619 79.9762 7.1143 ***0
H L1 Tip 70.9714 70.8286 -0.1428 0.878
V L1 Apex 92.7238 99.6381 6.9143 ***0
H L1 Apex 57.0857 56.3619 -0.7238 0.431
*p<.05
** p<.005
*** p<.001
(H = Horizontal Measure; V = Vertical Measure)
63
Table 3.5 Group 2 Pre-Treatment Vs. Post-Treatment
Variable T1 T2 !T2-T1 Sig
V Nasion -9.1966 -9.2000 -0.0034 0.745
H Nasion 74.8724 74.9000 0.0276 0.637
V Pronasale 40.1310 44.7621 4.6311 ***0
H Pronasale 101.4414 103.0793 1.6379 **0.01
V Subnasale 53.1069 57.2828 4.1759 ***0
H Subnasale 86.7207 87.0207 0.3000 0.556
V Labrale Superius 67.1586 71.669 4.5104 ***0
H Labrale Superius 88.3931 87.7759 -0.6172 0.326
V Stomion Superius 74.8207 78.6172 3.7965 ***0
H Stomion Superius 80.2414 79.9138 -0.3276 0.656
V Stomion Inferius 75.8034 79.4103 3.6069 ***0
H Stomion Inferius 79.9517 79.7724 -0.1793 0.81
V Labrale Inferius 83.3828 87.5207 4.1379 ***0
H Labrale Inferius 83.8586 83.8621 0.0035 0.996
V Pogion’ 108.1103 113.4828 5.3725 ***0
H Pogion’ 73.7966 72.8483 -0.9483 0.289
V ANS 47.7379 50.9931 3.2552 ***0
H ANS 72.0586 71.1207 -0.9379 0.088
V PNS 45.3379 46.5276 1.1897 *0.024
H PNS 16.4276 15.3586 -1.0690 0.146
V A Point 51.5655 55.1517 3.5862 ***0
H A Point 68.9414 67.6759 -1.2655 *0.04
V B Point 94.6897 100.4276 5.7379 ***0
H B Point 61.2414 59.7207 -1.5207 *0.042
V Pogonion 106.2793 112.2241 5.9448 ***0
H Pogonion 60.8172 59.3759 -1.4413 0.076
V Gnathion 106.2793 112.2241 5.9448 ***0
H Gnathion 60.8172 59.3759 -1.4413 *0.044
V Menton 113.5724 120.2 6.6276 ***0
H Menton 53.1345 51.2828 -1.8517 *0.026
V Gonion 74.2448 78.1759 3.9311 ***0
H Gonion -11.6310 -14.4897 -2.8587 ***0
V Condylion 22.0069 23.131 1.1241 0.202
H Condylion -20.4931 -21.0069 -0.5138 0.294
V Post FOP 67.5276000 71.5069 3.9793 ***0
64
Table 3.5 (Continued)
Variable T1 T2 !T2-T1 Sig
H Post FOP 31.1517 31.7414 0.5897 0.325
V Ant FOP 77.4966 80.5793 3.0827 ***0
H Ant FOP 72.6034 71.4517 -1.1517 0.063
V U6 Apex 49.3586 53.1345 3.7759 ***0
H U6 Apex 44.1552 43.7379 -0.4173 0.604
V L6 Apex 89.3000 93.7966 4.4966 ***0
H L6 Apex 31.9862 33.3828 1.3966 *0.031
V L6 Tip 69.9448 74.0828 4.1380 ***0
H L6 Tip 41.8207 42.2414 0.4207 0.518
V U1 Tip 77.5345 81.2172 3.6827 ***0
H U1 Tip 72.3552 71.169 -1.1862 0.063
V U1 Apex 51.6310 55.5517 3.9207 ***0
H U1 Apex 63.2724 62.1276 -1.1448 0.065
V L1 Tip 74.2448 79.769 5.5242 ***0
H L1 Tip 69.3517 69.0966 -0.2551 0.683
V L1 Apex 93.6241 98.3862 4.7621 ***0
H L1 Apex 55.6103 54.4276 -1.1827 0.148
* p<.05
** p<.005
*** p<.001
( H = Horizontal Measure; V = Vertical Measure)
65
Table 3.6 Group 3 Pre-Treatment Vs. Post-Treatment
Variable T1 T2 !T2-T1 Sig
V Nasion -8.9879 -8.997 -0.0091 0.374
H Nasion 73.2333 73.2909 0.0576 0.275
V Pronasale 40.703 46.4364 5.7334 ***0
H Pronasale 98.8152 99.3212 0.506 0.32
V Subnasale 52.4242 57.6182 5.194 ***0
H Subnasale 84.3636 83.5636 -0.8 0.116
V Labrale Superius 66.9152 72.0061 5.0909 ***0
H Labrale Superius 86.1273 84.8576 -1.2697 *0.022
V Stomion Superius 74.0848 78.7636 4.6788 ***0
H Stomion Superius 78.3091 76.1333 -2.1758 ***0
V Stomion Inferius 75.6121 79.7818 4.1697 ***0
H Stomion Inferius 77.9273 75.8939 -2.0334 **0.001
V labrale Inferius 83.0394 88.7909 5.7515 ***0
H Labrale Inferius 81.6061 80.1939 -1.4122 *0.018
V Pogion' 104.997 112.0848 7.0878 ***0
H Pogion' 72.4697 69.3909 -3.0788 **0.001
V ANS 47.0939 50.8697 3.7758 ***0
H ANS 71.5424 69.803 -1.7394 **0.019
V PNS 45.5242 46.9121 1.3879 ***0
H PNS 16.7061 14.6212 -2.0849 **0.001
V A Point 51.0606 55.0667 4.0061 ***0
H A Point 67.9273 65.9576 -1.9697 *0.005
V B Point 93.7909 99.8061 6.0152 ***0
H B Point 58.9879 55.5909 -3.397 ***0
V Pogonion 107.3212 114.1424 6.8212 ***0
H Pogonion 58.6848 55.3364 -3.3484 ***0
V Gnathion 112.5182 119.3152 6.797 ***0
H Gnathion 55.8091 51.9364 -3.8727 ***0
V Menton 113.6394 120.1485 6.5091 ***0
H Menton 50.9333 46.8788 -4.0545 ***0
V Gonion 76.9364 78.4152 1.4788 *0.005
H Gonion -11.303 -16.403 -5.1 ***0
V Condylion 21.4606 19.7818 -1.6788 *0.021
H Condylion -19.5061 -20.6545 -1.1484 *0.006
V Post FOP 67.8091 71.0909 3.2818 ***0
H Post FOP 30.4242 29.6455 -0.7787 0.171
V Ant FOP 77.7667 82.2818 4.5151 ***0
H Ant FOP 71.4303 68.5333 -2.897 ***0
V U6 Apex 49.7667 53.6485 3.8818 ***0
66
Table 3.6 (Continued)
!
Variable T1 T2 !T2-T1 Sig
H U6 Apex 43.2333 41.8515 -1.3818 *0.015
V L6 Apex 89.6576 93.6636 4.006 ***0
H L6 Apex 30.1545 30.6091 0.4546 0.622
V L6 Tip 70.0606 74.3121 4.2515 ***0
H L6 Tip 39.7182 39.9727 0.2545 0.723
V U1 Tip 77.3576 82.0909 4.7333 ***0
H U1 Tip 71.5818 68.4182 -3.1636 ***0
V U1 Apex 51.4848 57.5879 6.1031 ***0
H U1 Apex 61.7727 60.0848 -1.6879 **0.003
V L1 Tip 74.003 80.1758 6.1728 ***0
H L1 Tip 67.203 65.8545 -1.3485 *0.018
V L1 Apex 92.8667 97.5273 4.6606 ***0
H L1 Apex 54.3545 51.0303 -3.3242 ***0
* p<.05
** p<.005
*** p<.001
( H= Horizontal measures; V = Vertical Measures)
67
Table 3.7 Descriptive Statistics for Significant Horizontal Landmarks
at the Post Treatment Time Point
Landmark Group N Mean
Std.
Deviation
Std.
Error
H Labrale Superius 1.00 21 90.8762 8.18113 1.78527
2.00< 29 87.7759 6.50805 1.20852
3.00 33 84.8576 7.90668 1.37638
Total 83 87.4000 7.80574 .85679
H Stomion Superius 1.00 21 82.5524 8.29244 1.80956
2.00< 29 79.9138 7.23714 1.34390
3.00 33 76.1333 8.17724 1.42348
Total 83 79.0783 8.22065 .90233
H Stomion Inferius 1.00 21 82.3143 8.30170 1.81158
2.00< 29 79.7724 7.24731 1.34579
3.00 33 75.8939 8.24541 1.43534
Total 83 78.8735 8.25628 .90624
H Labrale Inferius 1.00 21 86.7619 9.05635 1.97626
2.00< 29 83.8621 7.71674 1.43296
3.00 33 80.1939 8.75171 1.52348
Total 83 83.1373 8.79001 .96483
< denotes Group 2 landmarks that show no significant differences at the
post treatment time point; data given for comparison purposes
Table 3.8 ANOVA for Significant Horizontal Landmarks at the Post
Treatment Time Point
Sum of
Squares df
Mean
Square F Sig.
Between
Groups 471.168 2 235.584 4.165 *0.019
Within Groups 4525.052 80 56.563
H Labrale
Superius
Total 4996.220 82
Between
Groups 559.901 2 279.950 4.496 *0.014
Within Groups 4981.580 80 62.270
H Stomion
Superius
Total 5541.481 82
Between
Groups 565.019 2 282.510 4.498 *0.014
Within Groups 5024.602 80 62.808
H Stomion
Inferius
Total 5589.622 82
Between
Groups 577.018 2 288.509 4.008 *0.022
Within Groups 5758.657 80 71.983
H Labrale
Inferius
Total 6335.674 82
* p<.05
** p<.005
*** p<.001
68
Table 3.9 Tukey Post Hoc Multiple Comparisons Of Significant
Horizontal Landmarks at the Post Treatment Time Point
Dependent Variable
(I)
GROUP (J) GROUP
Mean
Difference
(I-J)
Std.
Error Sig.
H Labrale Superius 1.00 2.00 3.10033 2.15498 0.326
3.00 6.01861(*) 2.09941 *0.014
2.00< 1.00 -3.10033 2.15498 0.326
3.00 2.91829 1.91429 0.285
3.00 1.00 -6.01861(*) 2.09941 *0.014
2.00 -2.91829 1.91429 0.285
H Stomion Superius 1.00 2.00 2.63859 2.26107 0.476
3.00 6.41905(*) 2.20277 *0.013
2.00< 1.00 -2.63859 2.26107 0.476
3.00 3.78046 2.00853 0.150
3.00 1.00 -6.41905(*) 2.20277 *0.013
2.00 -3.78046 2.00853 0.150
H Stomion Superius 1.00 2.00 2.54187 2.27082 0.505
3.00 6.42035(*) 2.21226 *0.013
2.00< 1.00 -2.54187 2.27082 0.505
3.00 3.87847 2.01719 0.139
3.00 1.00 -6.42035(*) 2.21226 *0.013
2.00 -3.87847 2.01719 0.139
H Labrale Superius 1.00 2.00 2.89984 2.43104 0.461
3.00 6.56797(*) 2.36835 *0.019
2.00< 1.00 -2.89984 2.43104 0.461
3.00 3.66813 2.15951 0.212
3.00 1.00 -6.56797(*) 2.36835 *0.019
2.00 -3.66813 2.15951 0.212
* p<.05
** p<.005
*** p<.001
< denotes group 2 landmarks that show no significant differences
at the post treatment time point; data given for comparison
purposes
69
Table 3.10 Descriptive Statistics for the Significant
Vertical Landmark at the Post Treatment Time Point
Landmark Group N Mean
Std.
Deviation
Std.
Error
V Condylion 1.00< 21 22.7810 5.82019 1.27007
2.00 29 23.1310 5.20763 .96703
3.00 33 19.7818 4.78621 .83317
Total 83 21.7108 5.38202 .59075
< denotes group 1 landmarks that show no significant differences
at the post treatment time point; data given for comparison
purposes
Table 3.11 ANOVA for the Significant Vertical Measure at the Post
Treatment Time Point
Sum of
Squares df
Mean
Square F Sig.
V Condylion Between
Groups 205.337 2 102.668 3.785 *.027
Within
Groups 2169.884 80 27.124
Total 2375.220 82
* p<.05
** p<.005***
*** p<.001
Table 3.12 Tukey’s Post Hoc Multiple Comparisons of the Significant
Vertical Landmark at the Post Treatment Time Point
Dependent
Variable
(I)
GROUP
(J)
GROUP
Mean
Difference
(I-J)
Std.
Error Sig.
V Condylion 1.00< 2.00 -.35008 1.49228 0.970
3.00 2.99913 1.45380 0.104
2.00 1.00< .35008 1.49228 0.970
3.00 3.34922(*) 1.32560 *0.036
3.00 1.00< -2.99913 1.45380 0.104
2.00 -3.34922(*) 1.32560 *0.036 * p<.05
** p<.005
*** p<.001
< denotes group 1 landmarks that show no significant differences
at the post treatment time point; data given for comparison
purposes
70
Table 3.13 Comparison of Mandibular Horizontal Measures at the T1 and
T2 Time Points
Landmark Group N T1 T2 change
H BPt 1 21 61.9048 60.935 -0.9698
2 29 61.2414 59.7207 -1.5207
3 33 58.9879 55.5909 -3.397
Total 83 60.5133 58.3549 -2.1584
H Pog 1 21 61.3857 59.881 -1.5047
2 29 60.8172 59.3759 -1.4413
3 33 58.6848 55.3364 -3.3484
Total 83 60.1133 57.8976 -2.2157
H Gn 1 21 58.6762 56.4238 -2.2524
2 29 58.1448 56.4414 -1.7034
3 33 55.8091 51.9364 -3.8727
Total 83 57.3506 54.6458 -2.7048
H Me 1 21 54.7905 51.8095 -2.981
2 29 53.1345 51.2828 -1.8517
3 33 50.9333 46.8788 -4.0545
Total 83 52.6783 49.6651 -3.0132
H Go 1 21 -11.419 -15.119 -3.7
2 29 -11.631 -14.4897 -2.8587
3 33 -11.303 -16.403 -5.1
Total 83 -11.447 -15.4096 -3.9626
H Co 1 21 -19.6095 -20.8905 -1.281
2 29 -20.4931 -21.0069 -0.5138
3 33 -19.5061 -20.6545 -1.1484
Total 83 -19.8771 -20.8373 -0.9602
71
Table 3.14 Comparison of Mandibular Vertical Measures at T1 and T2
Landmark Group N T1 Mean T2 Mean Change
V BPt 1 21 94.6571 101.0381 6.381
2 29 94.6897 100.4276 5.7379
3 33 93.7909 99.8061 6.0152
Total 83 94.3241 100.3349 6.0108
V Pog 1 21 107.0714 116.8333 9.7619
2 29 106.2793 112.2241 5.9448
3 33 107.3212 114.1424 6.8212
Total 83 106.894 114.153 7.259
V Gn 1 21 111.2476 120.581 9.3334
2 29 111.7655 118.469 6.7035
3 33 112.5182 119.3152 6.797
Total 83 111.9337 119.3398 7.4061
V Me 1 21 112.3762 121.3429 8.9667
2 29 113.5724 120.2 6.6276
3 33 113.6394 120.1485 6.5091
Total 83 113.2964 120.4687 7.1723
V Go 1 21 74.1714 78.6714 4.5
2 29 74.2448 78.1759 3.9311
3 33 76.9364 78.4152 1.4788
Total 83 75.2964 78.3964 3.1
V Co 1 21 23.4714 22.781 -0.6904
2 29 22.0069 23.131 1.1241
3 33 21.4606 19.7818 -1.6788
Total 83 22.1602 21.7108 -0.4494
72
Table 3.15 Comparison of the Horizontal Maxillary Landmarks at T1 and
T2
Landmark Group N T1 Mean T2 Mean Change
H ANS 1 21 70.7095 69.8714 -0.8381
2 29 72.0586 71.1207 -0.9379
3 33 71.5424 69.803 -1.7394
Total 83 71.512 70.2807 -1.2313
H PNS 1 21 18.2857 16.9762 -1.3095
2 29 16.4276 15.3586 -1.069
3 33 16.7061 14.6212 -2.0849
Total 83 17.0084 15.4747 -1.5337
H APt 1 21 68.5048 67.5667 -0.9381
2 29 68.9414 67.6759 -1.2655
3 33 67.9273 65.9576 -1.9697
Total 83 68.4277 66.9651 -1.4626
Table 3.16 Comparison of Vertical Maxillary Landmarks at T1 and T2
Landmark Group N T1 Mean T2 Mean Change
V ANS 1 21 46.5048 50.6619 4.1571
2 29 47.7379 50.9931 3.2552
3 33 47.0939 50.8697 3.7758
Total 83 47.1699 50.8602 3.6903
V PNS 1 21 44.3952 47.6619 3.2667
2 29 45.3379 46.5276 1.1897
3 33 45.5242 46.9121 1.3879
Total 83 45.1735 46.9675 1.794
V APt 1 21 49.4667 54.3952 4.9285
2 29 51.5655 55.1517 3.5862
3 33 51.0606 55.0667 4.0061
Total 83 50.8337 54.9265 4.0928
73
Table 3.17 Comparison of Horizontal Soft Tissue Landmarks at T1 and T2
Landmark Group N T1 Mean T2 Mean Change
1 21 99.1286 102.481 3.3524
2 29 101.4414 103.0793 1.6379
3 33 98.8152 99.3212 0.506
H PRN
Total 83 99.812 101.4337 1.6217
1 21 85.7286 87.0762 1.3476
2 29 86.7207 87.0207 0.3
3 33 84.3636 83.5636 -0.8
H SBN
Total 83 85.5325 85.6602 0.1277
1 21 90.4857 90.8762 0.3905
2 29 88.3931 87.7759 -0.6172
3 33 86.1273 84.8576 -1.2697
H LS
Total 83 88.0217 87.4 -0.6217
1 21 82.919 82.5524 -0.3666
2 29 80.2414 79.9138 -0.3276
3 33 78.3091 76.1333 -2.1758
H SS
Total 83 80.1506 79.0783 -1.0723
1 21 82.2238 82.3143 0.0905
2 29 79.9517 79.7724 -0.1793
3 33 77.9273 75.8939 -2.0334
H SI
Total 83 79.7217 78.8735 -0.8482
1 21 86.3 86.7619 0.4619
2 29 83.8586 83.8621 0.0035
3 33 81.6061 80.1939 -1.4122
H LI
Total 83 83.5807 83.1373 -0.4434
1 21 75.0667 75.3333 0.2666
2 29 73.7966 72.8483 -0.9483
3 33 72.4697 69.3909 -3.0788
H POG’
Total 83 73.5904 72.1024 -1.488
74
Table 3.18 Comparison of Vertical Soft Tissue Landmarks at T1 and T2
Landmark Group N T1 Mean T2 Mean Change
1 21 37.4381 44.1048 6.6667
2 29 40.131 44.7621 4.6311
3 33 40.703 46.4364 5.7334
V PRN
Total 83 39.6771 45.2614 5.5843
1 21 50.5952 56.0238 5.4286
2 29 53.1069 57.2828 4.1759
3 33 52.4242 57.6182 5.194
V SBN
Total 83 52.2 57.0976 4.8976
1 21 64.6952 70.619 5.9238
2 29 67.1586 71.669 4.5104
3 33 66.9152 72.0061 5.0909
V LS
Total 83 66.4386 71.5373 5.0987
1 21 73.4619 79.6762 6.2143
2 29 74.8207 78.6172 3.7965
3 33 74.0848 78.7636 4.6788
V SS
Total 83 74.1843 78.9434 4.7591
1 21 74.6619 80.6 5.9381
2 29 75.8034 79.4103 3.6069
3 33 75.6121 79.7818 4.1697
V SI
Total 83 75.4386 79.859 4.4204
1 21 82.6143 89.6571 7.0428
2 29 83.3828 87.5207 4.1379
3 33 83.0394 88.7909 5.7515
V LI
Total 83 83.0518 88.5663 5.5145
1 21 106.2333 114.019 7.7857
2 29 108.1103 113.4828 5.3725
3 33 104.997 112.0848 7.0878
V POG’
Total 83 106.3976 113.0627 6.6651
75
Table 3.19 Comparison of Horizontal Dental Landmarks at T1 and T2
Landmark Group N T1 Mean T2 Mean Change
1 21 31.9143 32.1667 0.2524
2 29 31.1517 31.7414 0.5897
3 33 30.4242 29.6455 -0.7787
H PFOP
Total 83 31.0554 31.0157 -0.0397
1 21 74.5857 73.319 -1.2667
2 29 72.6034 71.4517 -1.1517
3 33 71.4303 68.5333 -2.897
H AFOP
Total 83 72.6386 70.7639 -1.8747
1 21 45.1 44.9905 -0.1095
2 29 44.1552 43.7379 -0.4173
3 33 43.2333 41.8515 -1.3818
H U6A
Total 83 44.0277 43.3048 -0.7229
1 21 33.2524 34.0571 0.8047
2 29 31.9862 33.3828 1.3966
3 33 30.1545 30.6091 0.4546
H L6A
Total 83 31.5783 32.4506 0.8723
1 21 41.8 43.3143 1.5143
2 29 41.8207 42.2414 0.4207
3 33 39.7182 39.9727 0.2545
H L6C
Total 83 40.9795 41.6108 0.6313
1 21 74.6905 73.2381 -1.4524
2 29 72.3552 71.169 -1.1862
3 33 71.5818 68.4182 -3.1636
H U1C
Total 83 72.6386 70.5988 -2.0398
1 21 62.5905 62.4286 -0.1619
2 29 63.2724 62.1276 -1.1448
3 33 61.7727 60.0848 -1.6879
H U1A
Total 83 62.5036 61.3916 -1.112
1 21 70.9714 70.8286 -0.1428
2 29 69.3517 69.0966 -0.2551
3 33 67.203 65.8545 -1.3485
H L1I
Total 83 68.9072 68.2458 -0.6614
1 21 57.0857 56.3619 -0.7238
2 29 55.6103 54.4276 -1.1827
3 33 54.3545 51.0303 -3.3242
H L1A
Total 83 55.4843 53.5663 -1.918
76
Table 3.20 Comparison of Vertical Dental Landmarks at T1 and T2
Landmark Group N T1 Mean T2 Mean Change
1 21 66.1714 71.7381 5.5667
2 29 67.5276 71.5069 3.9793
3 33 67.8091 71.0909 3.2818
V PFOP
Total 83 67.2964 71.4 4.1036
1 21 76.819 82.1524 5.3334
2 29 77.4966 80.5793 3.0827
3 33 77.7667 82.2818 4.5151
V AFOP
Total 83 77.4325 81.6542 4.2217
1 21 48.119 53.5 5.381
2 29 49.3586 53.1345 3.7759
3 33 49.7667 53.6485 3.8818
V U6A
Total 83 49.2072 53.4313 4.2241
1 21 89.0095 95.4857 6.4762
2 29 89.3 93.7966 4.4966
3 33 89.6576 93.6636 4.006
V L6A
Total 83 89.3687 94.1711 4.8024
1 21 68.081 74.3286 6.2476
2 29 69.5828 73.669 4.0862
3 33 69.8697 73.5909 3.7212
V U6C
Total 83 69.3169 73.8048 4.4879
1 21 68.2619 74.9143 6.6524
2 29 69.9448 74.0828 4.138
3 33 70.0606 74.3121 4.2515
V L6C
Total 83 69.5651 74.3843 4.8192
1 21 76.5048 81.8476 5.3428
2 29 77.5345 81.2172 3.6827
3 33 77.3576 82.0909 4.7333
V U1I
Total 83 77.2036 81.7241 4.5205
1 21 49.2714 55.3381 6.0667
2 29 51.631 55.5517 3.9207
3 33 51.4848 57.5879 6.1031
V U1A
Total 83 50.9759 56.3072 5.3313
1 21 72.8619 79.9762 7.1143
2 29 74.2448 79.769 5.5242
3 33 74.003 80.1758 6.1728
V L1I
Total 83 73.7988 79.9831 6.1843
1 21 92.7238 99.6381 6.9143
2 29 93.6241 98.3862 4.7621
3 33 92.8667 97.5273 4.6606
V L1A
Total 83 93.0952 98.3614 5.2662
77
Discussion
Design
The design of this retrospective study was aimed to
produce a truly randomized sample without selection bias.
To this end, all of the initial 200 patients were included
in the study despite the resulting occlusion or amount of
gingival display produced or eliminated during orthodontic
treatment. Because the change in gingival display obtained
during orthodontic treatment was the sole factor used to
create the groups, without respect to the initial gingival
display presented, the subjects in the “greatest increase
in gingival display” group could or could not have obtained
a “gummy” smile during orthodontic treatment, just as those
in the “greatest decrease in gingival display” group could
or could not have obtained a certain result. This study
investigated the change in gingival display or relation of
the upper lip to the maxillary teeth during treatment and
attempted to determine what, if any, cephalometric landmark
changes occurred to produce this change in lip drape
without introducing the selection bias that would be
produced by selecting only those that had excessive
gingival display after orthodontic treatment as has been
done in the past.
78
Findings
This study evaluated the pre-treatment and post-
treatment cephalometric radiographs of three groups of
subjects that experienced different changes in gingival
display during orthodontic treatment. The purpose of this
study was to determine if there are any pre-treatment
cephalometric characteristics that are associated with the
tendency to develop a gingival smile during orthodontic
treatment and what cephalometric changes occur to produce
changes in gingival display.
The ANOVA found no significant differences between the
three groups at the pre-treatment time point for any of the
variables. However, group 1 appears to have the tendency
to have more protrusive lips, a more forward dentition, a
more forward positioned mandible, and shorter ramus than
the average group. On the contrary, group 3 had the
tendency to have the lips, dentition, and mandible
positioned posteriorly and a longer ramus relative to the
average group.
The paired T tests revealed many significant vertical
changes between the T1 and T2 time points, as would be
expected in subjects beginning treatment between the age of
10 and 14; this effect is due to growth. All vertical
measures were significant within each group between the T1
79
and T2 time points except for Nasion and Condylion. This
indicates that all groups changed significantly vertically
during the treatment period. However, further
investigation suggests that group 1 had the tendency to
obtain the greatest vertical changes, followed by group 3,
and finally group 2. In fact, group 1 obtained the
greatest vertical changes in all variables except condylion
and the maxillary incisor apex.
The horizontal measures demonstrated more variability.
While all groups had some significant horizontal
differences within the group from the T1 to T2 time period,
Group 3 (the greatest increase group) had more variables
change significantly in the horizontal direction from the
T1 to T2 time period that the other groups.
The significant horizontal changes in Group 1, the
greatest decrease group, occurred at pronasale, subnasale,
menton, and gonion suggesting that only the nasal soft
tissue and the lower border of the mandible changed
significantly in the horizontal direction. The data
reveals that the soft tissue moved forward as would be
expected, and the lower border of the mandible moved
backward. The other tendencies, although not significant,
were for the soft tissue and mandibular first molar to move
forward, the teeth to move relatively little horizontally,
80
although slightly back, and the maxilla and other
mandibular points to move backward.
In group 2, only pronasale, A point, B point,
Gnathion, menton, gonion, and L-6 Apex changed
significantly in the horizontal direction from T1 to T2.
The data suggests that the maxilla and mandible moved
significantly in the backward direction, while pronasale
and the mandibular first molar apex moved forward. The
other tendencies, although not significant, include the
soft tissue remaining relatively the same, the teeth moving
forward, and the other maxillary and mandibular points
moving backward.
In Group 3, all horizontal measures were significant
with the exception of Nasion, Pronasale, subnasale,
Posterior Functional Occlusal Plane, and the mandibular
first molar tip and apex. Further examination reveals that
all significant horizontal changes in Group 3 occurred in
the backward direction. In fact, all horizontal changes in
the soft tissue, maxilla, mandible, and teeth were in the
backward direction with the exception of nasion, pronasale,
and the mandibular first molar.
The mean horizontal and vertical measures of each of
the landmarks were plotted on an X-Y axis and used to
produce a graphical representation of the changes from T1
81
to T2 for each of the groups.(See Figures 3.6, 3.7, and
3.8)
Figure 3.6
Group 1
82
Figure 3.7
Group 2
83
Figure 3.8
Group 3
84
From these figures it is apparent that all three
groups experienced significant downward change during
treatment, probably due to both growth and the extrusive
effects of treatment. However, group 1 experienced the most
vertical change, followed by group 3, and finally by group
2. While the maxilla and mandible move slightly in the
backward direction in groups 1 and 2, the soft tissue,
teeth,and overall growth vector tend to be in a downward
and forward direction, although more downward in the group
1. In group 3, all variables have a downward and backward
vector with the exception of the tip of the nose and the
mandibular molar.
Although the ANOVA did not detect any significant
differences in the horizontal position of the maxilla,
mandible, or teeth between the groups at the post treatment
time point, it appears that the cumulative effects of the
individual components affected the soft tissue of the lips
(labrale superius, stomion superius, stomion inferius, and
labrale inferius) to a significant degree between the two
extreme groups (groups 1 and 3). The soft tissue lips were
significantly further back in the greatest increase group,
group 3, than the greatest decrease group, group 1, at the
post treatment time point. This is not surprising as the
average lips moved backward during treatment in group 3,
85
while the lips stayed relatively the same, or moved
slightly forward in group 1. Because the ANOVA found no
significant differences in these or any other variable at
the pretreatment time point, these differences can be
attributed to a change that occurred during treatment.
The only significant vertical measure was Condylion
between groups 2 and 3. It appears that the condyle moved
significantly more in an upward direction in the greatest
increase group (group 3) than the average group (group 2),
which stayed relatively the same. Group 1 had a tendency to
have a vertical vector of growth as well, although not to a
significant degree. The other mandibular measures showed
similar amounts of downward change, with group 1 having a
slight tendency to obtain more downward change at the
pogonion and gnathion measures, followed by group 3, and
finally group 2. This trend for group 1 to obtain the
greatest vertical change was apparent in the maxillary and
dental vertical measures as well. However, the trend for
group 3 to obtain greater vertical changes than group 2 was
not as clear in these measures.
The soft tissues demonstrated some interesting post
treatment tendencies. There appears to be a tendency for
pronasale, subnasale, and labrale superius, stomion
superius, stomion inferius, and labrale inferius to start
86
treatment higher vertically in the greatest decrease group
than the greatest increase group. However, at the post
treatment time point, while pronasale, subnasale, and
labrale superius, remain more superior vertically in the
greatest decrease group, stomion superius, stomion
inferius, and labrale inferius are positioned inferior to
the same landmarks in group 3. It appears that although
the nose and superior most point on the upper lip retain
their pattern, the point where the upper lip meets the
lower lip moves more inferiorly during treatment in group 1
than group 3.
This suggests that a lip response to treatment could
be an important factor in gingival display. The data
suggests that the lips responded to the vertical component
of growth (or change) in group 1, but did not respond in a
similar fashion in group 3. Perhaps this lack of downward
movement of the point where the lips meet in group 3 could
be a function of the significant movement of the lips
horizontally backward during treatment.
In summary, the soft tissue lips and skeletal vertical
condylion were the only significant differences found
between the groups. However, further examination and
plotting of the mean X-Y location of each of the points and
the pre and post treatment time points reveal a generalized
87
tendency for the greatest decrease group, or group 1 to
have a large vertical component, as well as a forward
component. The average group, or group 2, has the tendency
to change in the typical downward and forward pattern, and
the greatest increase group, or group 3, has the tendency
to change in a slightly increased downward and backward
direction. Further examination of the lips suggests that
the lips of subjects in group 1 responded vertically to the
inferior vector of change during treatment, while the lips
of subjects in group 3 did respond in a similar fashion.
This suggests that the significant horizontal (backward)
movement of the lips during treatment affected the downward
response.
Aside from dental and skeletal components, other
considerations in gingival display suggested by the
literature are sex, molar classification, and lip length.
In this study, 61% of the greatest increase group, group 3,
were female (39% male). Accordingly, 62% of the greatest
decrease group, group 1, were male (38% female. Although
weak, this tendency is in agreement with the literature,
which suggests that the tendency to have a gingival smile
is predominantly a female characteristic, while a low smile
line is predominantly a male characteristic.4,3,5,6 The middle
group was
88
59% female and 41% male, which closely resembles the
original sample which was 57% female and 43% male (see
Table 3.21.)
Table 3.21 Group Gender Percentages
Group Number of
Subjects
Mean Change
in Gingival
Display
Gender
Differences
Percentages
1
21 -2.55 8 Females
13 Males
38% Female
62% Male
2
29 0.65 17 Females
12 Males
59% Female
41% Male
3
33 3.75 20 Females
13 Males
61% Female
39% Male
When lip length of the sample is investigated, it
appears that although insignificant, group 3, who obtained
the greatest increase in gingival display, tends to have a
slightly shorter lip length at T1, while group 1, the
greatest decrease group, tends to have the longest lip
length at T1 (see Table 3.22). For this purpose, lip
length was defined as the vertical length from subnasale to
stomion superius as defined by Peck et al.3 This finding is
consistent with the findings of Peck et al. who found no
significant difference in upper lip length between his
gingival smile group and reference group3 and Schendel et
al. who reported that surgical vertical maxillary excess
patients have normal lip lengths.7 The mean lip lengths
found were also in accordance with the reported “normal”
89
lip lengths at approximately 22 mm. However, the tendency
found is contrary to the findings of Singer who found that
his group of gingival smile subjects had significantly
longer lip lengths than his non-gingival display sample.8
Table 3.22 Mean Lip Length at T1
Group N VSBN1 VSTMSU1 Lip Length
1 21 50.5952 73.4619 22.8667
2 29 53.1069 74.8207 21.7138
3 33 52.4242 74.0848 21.6606
When the lip length at the T2 time point is examined,
this same trend continues (see table 3.23). However, when
the change in lip length from T1 to T2 is examined, it
appears that the greatest decrease in gingival display
group, group 1, had an increase in lip length between the
T1 and T2 time points, while the average group and the
greatest increase groups experienced a decrease in lip
length during treatment (see table 3.24)
Table 3.23 Mean Lip Length at T2
Group N VSBN2 VSTMSU2 Lip Length
1 21 56.0238 79.6762 23.6524
2 29 57.2828 78.6172 21.3344
3 33 57.6182 78.7636 21.1454
Table 3.24 Change in Mean Lip Length from T1 to T2
Group N
T1 Lip
Length
T2 Lip
Length Change
1 21 22.8667 23.6524 0.7857
2 29 21.7138 21.3344 -0.3794
3 33 21.6606 21.1454 -0.5152
90
When the molar classification of the three groups is
considered it appears that groups 2 and 3 have a larger
number of subjects with a class I molar classification,
groups 1 and 3 have a large number of class II subjects,
and all groups have approximately the same number of class
III subjects (see Table 3.25).
Table 3.25 Group Molar Classification
Molar Classification Group 1 Group 2 Group 3
Class I 8 21 19
Crowding 2 4 4
Division 1 2 1 7
Division 2 5 0 0
Class II
Total 9 5 11
Class III 4 3 3
Upon further examination, 75% of group 2, the average
group, was Class I molar. While groups 1 and 3 have large
percentages of Class I’s as well, 38% and 58% respectively,
Class II’s also demonstrate a strong presence in these
groups (43% and 33%). The Class III subjects, although
small in number, make up almost 20% of the greatest
decrease group, group 1 (see Table 3.26).
91
Table 3.26 Molar Classification Percentages
Group Class I Class II Class III
1 (N=21) 38 % (8) 43 % (9) 19 % (4)
2 (N=29) 73 % (21) 17 % (5) 10 % (3)
3 (N=33) 58 % (19) 33 % (11) 9 % (3)
When the Class II subjects are examined, of the 25
Class II subjects in the sample, 36% of them are in group
1, the greatest decrease group, and it appears that the
majority of the Class II subjects in group 1 are Division 2
(56%). In fact, the only Class II Division 2 subjects in
the sample, are in the greatest decrease group. 20% of the
class II subjects were in group 2, the average group. The
majority of the Class II subjects in group 2 are Class II
crowding subjects (80%). 44% of the class II subjects are
in group 3, and the majority of the Class II subjects in
group 3, the greatest increase group, are division 1
(64%)(see Tables 3.27 and 3.28).
Table 3.27 Group Percentages of Class II’s
Group Number of Class II’s Percentage of Class
II Subjects in Group
1 9 36%
2 5 20%
3 11 44%
92
Table 3.28 Class II Division Percentages
Group Crowding Division 1 Division 2 Total
1 2 (22%) 2 (22%) 5 (56%) 9
2 4 (80%) 1 (20%) 0 5
3 4 (36%) 7 (64%) 0 11
Although no clear conclusions can be drawn from the
Class I group, it appears that the Class II division groups
tend to experience either a great decrease or a great
increase in gingival display during treatment. This study
suggests that Class II division 1 subjects tend to
experience a great increase in gingival display, and Class
II division 2 subjects experience a great decrease. It
also suggests a slight tendency for Class III subjects to
experience a great decrease.
In conclusion, while no significant differences were
found at the pre-treatment time point to suggest one
specific pretreatment characteristic to identify patients
with the predisposition to experience an increase or
decrease in gingival display during treatment, the tendency
was for the greatest decrease group, group 1, to be male,
to be Class I, Class II division 2, or Class III, to have
slightly protrusive lips, teeth and mandibles, and short
93
rami in comparison to the average group. The greatest
increase group, group 3, tended to be female, to be Class I
or Class II crowding or division 1, and to have posteriorly
positioned maxillary, mandibular, and dental landmarks in
comparison to the average group with the exception of
gonion, which suggests a high mandibular plane angle. They
also had longer rami than the average group. Therefore,
careful study of cephalometric measures in the pre-
treatment radiograph for a pattern of anteriorly or
posteriorly positioned landmarks while considering the sex
of the patient and molar classification, might help a
clinician to recognize those that will have the tendency to
lose or gain gingival display during treatment.
While no specific maxillary, mandibular, or dental
movements can be identified to determine which movements
during treatment caused these patterns of change, it
appears that a strong downward vector of growth (or change)
during treatment can cause a decrease in gingival display,
while a downward and backward vector can produce a great
increase. Therefore, mechanics aimed toward preventing a
backward horizontal vector of change and instead promoting
a forward horizontal vector, could help to prevent an
excessive increase in gingival display during treatment,
94
while controlling the vertical in forward growers appears
to be important in preventing an excessive decrease.
Conclusions
1. No significant differences were found at the pre-
treatment time point, therefore no specific dental,
skeletal, or soft tissue characteristic can be
identified to predict an increase or decrease in
gingival display during orthodontic treatment.
2. The only vertical significant difference was found at
the post-treatment time point between the average
change group and the greatest increase group at
condylion; this significance is possibly due to the
large envelope of error at the condylion landmark.
3. The significant horizontal differences were found
between the greatest increase and greatest decrease
groups at labrale superius, stomion superius, stomion
inferius, and labrale inferius (the lips). The lips
moved significantly backward in the greatest increase
group while they stayed relatively the same in the
greatest decrease group.
4. Although not significant, the greatest decrease group
had a tendency to be male, have slightly protrusive
lips, forward positioned teeth and mandibles, and
95
shorter rami in comparison to the average group at
the pre-treatment time point. They experienced a
large vertical vector in change from T1 to T2. The
greatest increase group had a tendency to be female,
have posteriorly positioned maxillary, mandibular,
and dental landmarks, and longer rami in comparison
to the average group at the pre-treatment time point.
They tend to have a downward and backward vector in
change from T1 to T2.
5. The change in gingival display during orthodontic
treatment is a very complex phenomenon that is a
culmination of the affects of changes that occur in
the dental, skeletal, and soft tissue components.
Further research is warranted.
96
Appendix A: Nonsignificant Pre-treatment Data
Table A.1 Pre-Treatment Horizontal Mandibular Measures Descriptive
Statistics
Landmark Group N Mean
Std.
Deviation Std. Error
APBPT1 1.00 21 61.9048 7.77628 1.69692
2.00 29 61.2414 7.13930 1.32574
3.00 33 58.9879 8.31147 1.44684
Total 83 60.5133 7.79302 .85540
APPOG1 1.00 21 61.3857 8.89260 1.94052
2.00 29 60.8172 7.62239 1.41544
3.00 33 58.6848 9.21158 1.60353
Total 83 60.1133 8.58203 .94200
APGN1 1.00 21 58.6762 9.54950 2.08387
2.00 29 58.1448 8.12604 1.50897
3.00 33 55.8091 9.53272 1.65943
Total 83 57.3506 9.04886 .99324
APME1 1.00 21 54.7905 10.33073 2.25435
2.00 29 53.1345 8.46502 1.57192
3.00 33 50.9333 9.67954 1.68499
Total 83 52.6783 9.46061 1.03844
APGO1 1.00 21 -11.4190 5.28182 1.15259
2.00 29 -11.6310 5.56431 1.03327
3.00 33 -11.3030 6.03057 1.04979
Total 83 -11.4470 5.62044 .61692
APCO1 1.00 21 19.6095 3.84459 .83896
2.00 29 20.4931 3.30270 .61330
3.00 33 19.5061 3.44329 .59940
97
Table A.2 ANOVA for Pre-Treatment Horizontal Mandibular Measures
Landmark
Sum of
Squares df Mean Square F Sig.
Between Groups 132.820 2 66.410 1.096 .339
Within Groups 4847.135 80 60.589
APBPT1
Total 4979.955 82
Between Groups 115.706 2 57.853 .781 .461
Within Groups 5923.690 80 74.046
APPOG1
Total 6039.395 82
Between Groups 133.610 2 66.805 .812 .448
Within Groups 6580.697 80 82.259
APGN1
Total 6714.307 82
Between Groups 200.204 2 100.102 1.122 .331
Within Groups 7139.057 80 89.238
APME1
Total 7339.261 82
Between Groups 1.683 2 .841 .026 .974
Within Groups 2588.644 80 32.358
APGO1
Total 2590.327 82
Between Groups 17.051 2 8.526 .696 .502
Within Groups 980.436 80 12.255
APCO1
Total 997.487 82
98
Table A.3 Pre-Treatment Vertical Mandibular Measures: Descriptive
Statistics
Group N Mean
Std.
Deviation Std. Error
VBPT1 1.00 21 94.6571 9.30589 2.03071
2.00 29 94.6897 8.75905 1.62651
3.00 33 93.7909 5.73663 .99862
Total 83 94.3241 7.76865 .85272
VPOG1 1.00 21 107.0714 10.14934 2.21477
2.00 29 106.2793 9.05891 1.68220
3.00 33 107.3212 6.77227 1.17890
Total 83 106.8940 8.44151 .92658
VGN1 1.00 21 111.2476 9.99828 2.18180
2.00 29 111.7655 8.81473 1.63685
3.00 33 112.5182 6.81425 1.18621
Total 83 111.9337 8.32478 .91376
VME1 1.00 21 112.3762 9.73539 2.12444
2.00 29 113.5724 8.50466 1.57928
3.00 33 113.6394 6.79333 1.18257
Total 83 113.2964 8.13111 .89251
VGO1 1.00 21 74.1714 6.67661 1.45696
2.00 29 74.2448 6.33283 1.17598
3.00 33 76.9364 7.24939 1.26196
Total 83 75.2964 6.84639 .75149
VCO1 1.00 21 23.4714 4.14562 .90465
2.00 29 22.0069 3.86993 .71863
3.00 33 21.4606 4.30319 .74909
Total 83 22.1602 4.14458 .45493
99
Table A.4 ANOVA for Pre-Treatment Vertical Mandibular Measures
Sum of
Squares df Mean Square F Sig.
Between Groups 15.586 2 7.793 .126 .881
Within Groups 4933.266 80 61.666
VBPT1
Total 4948.852 82
Between Groups 17.641 2 8.821 .121 .886
Within Groups 5825.606 80 72.820
VPOG1
Total 5843.247 82
Between Groups 21.979 2 10.989 .155 .856
Within Groups 5660.787 80 70.760
VGN1
Total 5682.766 82
Between Groups 23.874 2 11.937 .177 .838
Within Groups 5397.555 80 67.469
VME1
Total 5421.429 82
Between Groups 147.398 2 73.699 1.595 .209
Within Groups 3696.191 80 46.202
VGO1
Total 3843.589 82
Between Groups 52.939 2 26.469 1.562 .216
Within Groups 1355.620 80 16.945
VCO1
Total 1408.559 82
100
Table A.5 Pretreatment Horizontal Maxillary Measures: Descriptive
Statistics
Landmark
Group N Mean
Std.
Deviation
Std.
Error
APANS1 1.00 21 70.7095 4.26555 .93082
2.00 29 72.0586 5.39931 1.00263
3.00 33 71.5424 5.85657 1.01950
Total 83 71.5120 5.29607 .58132
APPNS1 1.00 21 18.2857 3.76713 .82206
2.00 29 16.4276 4.57469 .84950
3.00 33 16.7061 4.52299 .78735
Total 83 17.0084 4.37775 .48052
APAPT1 1.00 21 68.5048 4.35367 .95005
2.00 29 68.9414 5.52323 1.02564
3.00 33 67.9273 6.11455 1.06441
Total 83 68.4277 5.46129 .59945
Table A.6 ANOVA for Pretreatment Horizontal Maxillary Measures
Landmark
Sum of
Squares df Mean Square F Sig.
APANS1 Between Groups 22.219 2 11.109 .390 .678
Within Groups 2277.749 80 28.472
Total 2299.968 82
APPNS1 Between Groups 47.062 2 23.531 1.235 .296
Within Groups 1524.442 80 19.056
Total 1571.504 82
APAPT1 Between Groups 16.041 2 8.020 .264 .769
Within Groups 2429.665 80 30.371
Total 2445.706 82
101
Table A.7 Pretreatment Vertical Maxillary Measures: Descriptive
Statistics
Landmark
Group N Mean
Std.
Deviation
Std.
Error
VANS1 1.00 21 46.5048 4.36411 .95233
2.00 29 47.7379 3.92368 .72861
3.00 33 47.0939 4.10449 .71450
Total 83 47.1699 4.08733 .44864
VPNS1 1.00 21 44.3952 4.04419 .88251
2.00 29 45.3379 3.71785 .69039
3.00 33 45.5242 3.06982 .53439
Total 83 45.1735 3.54975 .38964
VAPT1 1.00 21 49.4667 4.08978 .89246
2.00 29 51.5655 3.94609 .73277
3.00 33 51.0606 3.88514 .67632
Total 83 50.8337 3.99699 .43873
Table A.8 ANOVA for Pretreatment Vertical Maxillary Measures
Sum of
Squares df
Mean
Square F Sig.
APANS1 Between
Groups 22.219 2 11.109 .390 .678
Within
Groups 2277.749 80 28.472
Total 2299.968 82
APPNS1 Between
Groups 47.062 2 23.531 1.235 .296
Within
Groups 1524.442 80 19.056
Total 1571.504 82
APAPT1 Between
Groups 16.041 2 8.020 .264 .769
Within
Groups 2429.665 80 30.371
Total 2445.706 82
102
Table A.9 – Pretreatment Horizontal Dental Measures: Descriptive
Statistics
N Mean
Std.
Deviation
Std.
Error
1.00 21 31.9143 5.63784 1.23028
2.00 29 31.1517 5.92119 1.09954
3.00 33 30.4242 5.60820 .97626
APU6DCUSP1
Total 83 31.0554 5.68778 .62431
1.00 21 74.5857 8.65981 1.88973
2.00 29 72.6034 6.57634 1.22120
3.00 33 71.4303 7.24027 1.26037
APANTFOP1
Total 83 72.6386 7.42123 .81459
1.00 21 45.1000 5.03329 1.09835
2.00 29 44.1552 5.46956 1.01567
3.00 33 43.2333 5.24289 .91267
APU6APEX1
Total 83 44.0277 5.26075 .57744
1.00 21 33.2524 7.25869 1.58398
2.00 29 31.9862 7.16986 1.33141
3.00 33 30.1545 7.05120 1.22746
APL6APEX1
Total 83 31.5783 7.16935 .78694
1.00 21 41.8000 6.78454 1.48051
2.00 29 41.8207 5.76878 1.07124
3.00 33 39.7182 6.47150 1.12654
APL6TIP1
Total 83 40.9795 6.32430 .69418
1.00 21 74.6905 8.70028 1.89856
2.00 29 72.3552 6.54209 1.21484
3.00 33 71.5818 7.40107 1.28836
APU1TIP1
Total 83 72.6386 7.48388 .82146
1.00 21 62.5905 4.69978 1.02558
2.00 29 63.2724 5.28711 .98179
3.00 33 61.7727 5.30190 .92294
APU1APEX1
Total 83 62.5036 5.13110 .56321
1.00 21 70.9714 8.42117 1.83765
2.00 29 69.3517 6.41737 1.19167
3.00 33 67.2030 7.68820 1.33834
APL1TIP1
Total 83 68.9072 7.53363 .82692
1.00 21 57.0857 8.77863 1.91565
2.00 29 55.6103 7.00349 1.30051
3.00 33 54.3545 7.72812 1.34529
APL1APEX1
Total 83 55.4843 7.74774 .85042
103
Table A.10 ANOVA for Pre-Treatment Horizontal Dental Measures
Sum of
Squares df Mean Square F Sig.
Between Groups 28.906 2 14.453 .441 .645
Within Groups 2623.859 80 32.798
APU6DCUSP1
Total 2652.765 82
Between Groups 127.832 2 63.916 1.165 .317
Within Groups 4388.285 80 54.854
APANTFOP1
Total 4516.117 82
Between Groups 45.441 2 22.721 .817 .445
Within Groups 2223.945 80 27.799
APU6APEX1
Total 2269.386 82
Between Groups 130.572 2 65.286 1.279 .284
Within Groups 4084.189 80 51.052
APL6APEX1
Total 4214.761 82
Between Groups 87.159 2 43.579 1.092 .340
Within Groups 3192.577 80 39.907
APL6TIP1
Total 3279.735 82
Between Groups 127.598 2 63.799 1.143 .324
Within Groups 4465.099 80 55.814
APU1TIP1
Total 4592.697 82
104
Table A.11 Pretreatment Vertical Dental Measures:
Descriptive Statistics
Landmark Group N Mean
Std.
Deviation Std. Error
VU6DCUSP1 1.00 21 66.1714 5.75935 1.25679
2.00 29 67.5276 5.98301 1.11102
3.00 33 67.8091 4.53296 .78909
Total 83 67.2964 5.36478 .58886
VANTFOP1 1.00 21 76.8190 6.02400 1.31455
2.00 29 77.4966 5.92353 1.09997
3.00 33 77.7667 5.07202 .88293
Total 83 77.4325 5.56904 .61128
VU6APEX1 1.00 21 48.1190 5.06178 1.10457
2.00 29 49.3586 4.94264 .91782
3.00 33 49.7667 3.40070 .59199
Total 83 49.2072 4.42057 .48522
VL6APEX1 1.00 21 89.0095 6.72398 1.46729
2.00 29 89.3000 6.35756 1.18057
3.00 33 89.6576 5.58570 .97235
Total 83 89.3687 6.08873 .66833
VU6TIP1 1.00 21 68.0810 5.74279 1.25318
2.00 29 69.5828 5.53954 1.02867
3.00 33 69.8697 4.56505 .79467
Total 83 69.3169 5.21477 .57240
VL6TIP1 1.00 21 68.2619 5.90995 1.28966
2.00 29 69.9448 5.70993 1.06031
3.00 33 70.0606 4.52569 .78782
Total 83 69.5651 5.31313 .58319
VU1TIP1 1.00 21 76.5048 5.93628 1.29540
2.00 29 77.5345 5.81392 1.07962
3.00 33 77.3576 4.75434 .82762
Total 83 77.2036 5.39734 .59244
VU1APEX1 1.00 21 49.2714 5.49819 1.19980
2.00 29 51.6310 5.37202 .99756
3.00 33 51.4848 4.61892 .80405
Total 83 50.9759 5.15297 .56561
VL1TIP1 1.00 21 72.8619 6.54358 1.42793
2.00 29 74.2448 6.64189 1.23337
3.00 33 74.0030 4.94580 .86095
Total 83 73.7988 5.94683 .65275
VL1APEX1 1.00 21 92.7238 7.09767 1.54884
2.00 29 93.6241 6.82331 1.26706
3.00 33 92.8667 5.51048 .95925
Total 83 93.0952 6.33956 .69586
105
Table A.11 (Continued)
Landmark Group N Mean
Std.
Deviation Std. Error
APU6DCUSP1 1.00 21 31.9143 5.63784 1.23028
2.00 29 31.1517 5.92119 1.09954
3.00 33 30.4242 5.60820 .97626
Total 83 31.0554 5.68778 .62431
Table A.12 ANOVA for Pretreatment Vertical Dental Measures
Sum of
Squares df Mean Square F Sig.
Between Groups 36.801 2 18.400 .634 .533
Within Groups 2323.228 80 29.040
VU6DCUSP1
Total 2360.029 82
Between Groups 11.707 2 5.853 .185 .831
Within Groups 2531.455 80 31.643
VANTFOP1
Total 2543.162 82
Between Groups 35.860 2 17.930 .916 .404
Within Groups 1566.536 80 19.582
VU6APEX1
Total 1602.396 82
Between Groups 5.600 2 2.800 .074 .929
Within Groups 3034.359 80 37.929
VL6APEX1
Total 3039.959 82
Between Groups 44.213 2 22.106 .809 .449
Within Groups 2185.683 80 27.321
VU6TIP1
Total 2229.896 82
Between Groups 47.949 2 23.974 .846 .433
Within Groups 2266.860 80 28.336
VL6TIP1
Total 2314.809 82
Between Groups 14.213 2 7.107 .239 .788
Within Groups 2374.556 80 29.682
VU1TIP1
Total 2388.769 82
Between Groups 82.004 2 41.002 1.565 .215
Within Groups 2095.347 80 26.192
VU1APEX1
Total 2177.352 82
Between Groups 25.579 2 12.789 .356 .702
Within Groups 2874.331 80 35.929
VL1TIP1
Total 2899.910 82
Between Groups 12.734 2 6.367 .155 .857
Within Groups 3282.845 80 41.036
VL1APEX1
Total 3295.578 82
Between Groups 28.906 2 14.453 .441 .645
Within Groups 2623.859 80 32.798
APU6DCUSP1
Total 2652.765 82
106
Table A.13 Pretreatment Measures for Non-significant Horizontal Soft
Tissue Landmarks:
Descriptive Statistics
N Mean
Std.
Deviation Std. Error
APPRN1 1.00 21 99.1286 4.72400 1.03086
2.00 29 101.4414 5.45832 1.01358
3.00 33 98.8152 6.11331 1.06419
Total 83 99.8120 5.62664 .61760
APSBN1 1.00 21 85.7286 5.00591 1.09238
2.00 29 86.7207 4.95280 .91971
3.00 33 84.3636 5.73971 .99916
Total 83 85.5325 5.32949 .58499
APLABSU1 1.00 21 90.4857 8.64010 1.88542
2.00 29 88.3931 6.62403 1.23005
3.00 33 86.1273 7.14568 1.24390
Total 83 88.0217 7.49429 .82261
APSTMSU1 1.00 21 82.9190 8.88328 1.93849
2.00 29 80.2414 7.02569 1.30464
3.00 33 78.3091 6.94007 1.20811
Total 83 80.1506 7.63074 .83758
APSTINF1 1.00 21 82.2238 9.53566 2.08085
2.00 29 79.9517 7.13516 1.32497
3.00 33 77.9273 7.01228 1.22068
Total 83 79.7217 7.85295 .86197
APLABIN1 1.00 21 86.3000 10.49486 2.29017
2.00 29 83.8586 7.98411 1.48261
3.00 33 81.6061 7.71889 1.34369
Total 83 83.5807 8.68172 .95294
APPOG1 1.00 21 75.0667 9.85507 2.15055
2.00 29 73.7966 8.41879 1.56333
3.00 33 72.4697 9.60753 1.67246
Total 83 73.5904 9.21900 1.01192
107
Table A.14 ANOVA for Non-significant Pretreatment Horizontal Measures
Sum of
Squares df Mean Square F Sig.
APPRN1 Between Groups 119.592 2 59.796 1.932 .152
Within Groups 2476.456 80 30.956
Total 2596.048 82
APSBN1 Between Groups 86.835 2 43.418 1.549 .219
Within Groups 2242.247 80 28.028
Total 2329.082 82
APLABSU1 Between Groups 249.931 2 124.966 2.295 .107
Within Groups 4355.550 80 54.444
Total 4605.481 82
APSTMSU1 Between Groups 273.097 2 136.549 2.427 .095
Within Groups 4501.610 80 56.270
Total 4774.707 82
APSTINF1 Between Groups 239.265 2 119.633 1.987 .144
Within Groups 4817.576 80 60.220
Total 5056.841 82
APLABIN1 Between Groups 286.200 2 143.100 1.942 .150
Within Groups 5894.329 80 73.679
Total 6180.529 82
APPOG1 Between Groups 88.446 2 44.223 .514 .600
Within Groups 6880.726 80 86.009
Total 6969.172 82
108
Table A.15 Pretreatment Vertical Measures for Soft Tissue Landmarks:
Descriptive Statistics
N Mean
Std.
Deviation
Std.
Error
VPRN1 1.00 21 37.4381 4.44032 .96896
2.00 29 40.1310 5.91488 1.09837
3.00 33 40.7030 5.08604 .88537
Total 83 39.6771 5.35073 .58732
VSBN1 1.00 21 50.5952 4.08295 .89097
2.00 29 53.1069 4.81426 .89399
3.00 33 52.4242 4.90510 .85387
Total 83 52.2000 4.72652 .51880
VLABSU1 1.00 21 64.6952 5.44495 1.18819
2.00 29 67.1586 6.56166 1.21847
3.00 33 66.9152 4.84033 .84259
Total 83 66.4386 5.66824 .62217
VSTMSU1 1.00 21 73.4619 6.72588 1.46771
2.00 29 74.8207 6.05837 1.12501
3.00 33 74.0848 5.00132 .87062
Total 83 74.1843 5.79730 .63634
VSTINF1 1.00 21 74.6619 6.62982 1.44674
2.00 29 75.8034 5.66969 1.05283
3.00 33 75.6121 5.23311 .91097
Total 83 75.4386 5.70945 .62669
VLABIN1 1.00 21 82.6143 9.11210 1.98842
2.00 29 83.3828 6.53917 1.21429
3.00 33 83.0394 6.40561 1.11507
Total 83 83.0518 7.13812 .78351
VPOG1 1.00 21 106.2333 8.96874 1.95714
2.00 29 108.1103 9.40351 1.74619
3.00 33 104.9970 7.09976 1.23591
Total 83 106.3976 8.44500 .92696
109
Table A.16 ANOVA for Pretreatment Vertical for Soft Tissue Landmarks
Sum of
Squares df Mean Square F Sig.
VPRN1 Between Groups 145.985 2 72.993 2.652 .077
Within Groups 2201.701 80 27.521
Total 2347.687 82
VSBN1 Between Groups 79.591 2 39.796 1.817 .169
Within Groups 1752.289 80 21.904
Total 1831.880 82
VLABSU1 Between Groups 86.354 2 43.177 1.356 .264
Within Groups 2548.222 80 31.853
Total 2634.577 82
VSTMSU1 Between Groups 23.030 2 11.515 .337 .715
Within Groups 2732.880 80 34.161
Total 2755.910 82
VSTINF1 Between Groups 17.522 2 8.761 .264 .769
Within Groups 2655.494 80 33.194
Total 2673.017 82
VLABIN1 Between Groups 7.201 2 3.601 .069 .933
Within Groups 4170.926 80 52.137
Total 4178.127 82
VPOG1 Between Groups 150.376 2 75.188 1.056 .353
Within Groups 5697.703 80 71.221
Total 5848.080 82
110
Appendix B: Non-significant Post Treatment Data
Table B.1 Post-Treatment Non-Significant Horizontal Mandibular
Measures: Descriptive Statistics
N Mean
Std.
Deviation
Std.
Error
APBPT2 1.00 20 60.9350 8.89673 1.98937
2.00 29 59.7207 8.00211 1.48596
3.00 33 55.5909 9.41041 1.63814
Total 82 58.3549 9.00615 .99456
APPOG2 1.00 21 59.8810 10.18571 2.22270
2.00 29 59.3759 8.57441 1.59223
3.00 33 55.3364 10.14254 1.76559
Total 83 57.8976 9.74547 1.06970
APGN2 1.00 21 56.4238 10.38335 2.26583
2.00 29 56.4414 9.05793 1.68202
3.00 33 51.9364 10.79363 1.87893
Total 83 54.6458 10.23134 1.12304
APME2 1.00 21 51.8095 10.35750 2.26019
2.00 29 51.2828 9.92033 1.84216
3.00 33 46.8788 11.27691 1.96306
Total 83 49.6651 10.70626 1.17516
APGO2 1.00 21 -15.1190 7.43442 1.62232
2.00 29 -14.4897 5.36119 .99555
3.00 33 -16.4030 5.84826 1.01805
Total 83 -15.4096 6.11231 .67091
APCO2 1.00 21 -20.8905 3.74725 .81772
2.00 29 -21.0069 3.63789 .67554
3.00 33 -20.6545 2.97291 .51752
Total 83 -20.8373 3.37894 .37089
111
Table B.2 ANOVA for Post-Treatment Mandibular Horizontal Measures
Sum of
Squares df Mean Square F Sig.
APBPT2 Between Groups 439.343 2 219.671 2.831 .065
Within Groups 6130.620 79 77.603
Total 6569.963 81
APPOG2 Between Groups 362.458 2 181.229 1.953 .149
Within Groups 7425.422 80 92.818
Total 7787.880 82
APGN2 Between Groups 402.141 2 201.071 1.966 .147
Within Groups 8181.645 80 102.271
Total 8583.786 82
APME2 Between Groups 428.654 2 214.327 1.911 .155
Within Groups 8970.515 80 112.131
Total 9399.169 82
APGO2 Between Groups 58.883 2 29.442 .784 .460
Within Groups 3004.669 80 37.558
Total 3063.552 82
APCO2 Between Groups 1.996 2 .998 .085 .918
Within Groups 934.219 80 11.678
Total 936.214 82
112
Table B.3 Post-Treatment Non-Significant Vertical Mandibular Measures:
Descriptive Statistics
N Mean
Std.
Deviation
Std.
Error
VBPT2 1.00 21 101.0381 10.46535 2.28373
2.00 29 100.4276 8.00548 1.48658
3.00 33 99.8061 6.65277 1.15810
Total 83 100.3349 8.13086 .89248
VPOG2 1.00 21 116.8333 11.22891 2.45035
2.00 29 112.2241 8.10871 1.50575
3.00 33 114.1424 7.22176 1.25715
Total 83 114.1530 8.75861 .96138
VGN2 1.00 21 120.5810 11.04272 2.40972
2.00 29 118.4690 8.21671 1.52581
3.00 33 119.3152 6.98946 1.21671
Total 83 119.3398 8.51604 .93476
VME2 1.00 21 121.3429 10.50155 2.29163
2.00 29 120.2000 7.98199 1.48222
3.00 33 120.1485 6.70854 1.16781
Total 83 120.4687 8.15345 .89496
VGO2 1.00 21 78.6714 8.89203 1.94040
2.00 29 78.1759 6.42360 1.19283
3.00 33 78.4152 7.06864 1.23049
Total 83 78.3964 7.27393 .79842
113
Table B.4 ANOVA for Non-Significant Post-Treatment Vertical Mandibular
Measures
Sum of
Squares df Mean Square F Sig.
VBPT2 Between Groups 19.862 2 9.931 .147 .863
Within Groups 5401.226 80 67.515
Total 5421.089 82
VPOG2 Between Groups 258.766 2 129.383 1.716 .186
Within Groups 6031.720 80 75.397
Total 6290.487 82
VGN2 Between Groups 54.362 2 27.181 .369 .693
Within Groups 5892.517 80 73.656
Total 5946.879 82
VME2 Between Groups 21.525 2 10.762 .159 .854
Within Groups 5429.734 80 67.872
Total 5451.259 82
VGO2 Between Groups 3.011 2 1.505 .028 .973
Within Groups 4335.618 80 54.195
Total 4338.629 82
114
Table B.5 Post-Treatment Horizontal Maxillary Measures: Descriptive
Statistics
N Mean
Std.
Deviation
Std.
Error
APANS2 1.00 21 69.8714 5.53698 1.20827
2.00 29 71.1207 5.68321 1.05535
3.00 33 69.8030 6.23987 1.08622
Total 83 70.2807 5.83826 .64083
APPNS2 1.00 21 16.9762 3.69282 .80584
2.00 29 15.3586 5.07779 .94292
3.00 33 14.6212 4.79269 .83430
Total 83 15.4747 4.68716 .51448
APAPT2 1.00 21 67.5667 5.84092 1.27459
2.00 29 67.6759 5.89053 1.09384
3.00 33 65.9576 6.03961 1.05136
Total 83 66.9651 5.92318 .65015
Table B.6 ANOVA for Post-Treatment Horizontal Maxillary Measures
N Mean
Std.
Deviation
Std.
Error
APANS2 1.00 21 69.8714 5.53698 1.20827
2.00 29 71.1207 5.68321 1.05535
3.00 33 69.8030 6.23987 1.08622
Total 83 70.2807 5.83826 .64083
APPNS2 1.00 21 16.9762 3.69282 .80584
2.00 29 15.3586 5.07779 .94292
3.00 33 14.6212 4.79269 .83430
Total 83 15.4747 4.68716 .51448
APAPT2 1.00 21 67.5667 5.84092 1.27459
2.00 29 67.6759 5.89053 1.09384
3.00 33 65.9576 6.03961 1.05136
Total 83 66.9651 5.92318 .65015
115
Table B.7 Post Treatment Vertical Maxillary Measures: Descriptive
Statistics
N Mean
Std.
Deviation
Std.
Error
VANS2 1.00 21 50.6619 4.08821 .89212
2.00 29 50.9931 3.50916 .65164
3.00 33 50.8697 4.16792 .72554
Total 83 50.8602 3.88289 .42620
VPNS2 1.00 21 47.6619 4.59124 1.00189
2.00 29 46.5276 3.27642 .60842
3.00 33 46.9121 3.82865 .66648
Total 83 46.9675 3.83673 .42114
VAPT2 1.00 21 54.3952 4.36182 .95183
2.00 29 55.1517 3.68856 .68495
3.00 33 55.0667 4.08631 .71133
Total 83 54.9265 3.98754 .43769
Table B.8 ANOVA for Post-Treatment Vertical Maxillary Measures
Sum of
Squares df Mean Square F Sig.
VANS2 Between Groups 1.341 2 .670 .043 .958
Within Groups 1234.958 80 15.437
Total 1236.299 82
VPNS2 Between Groups 15.840 2 7.920 .532 .590
Within Groups 1191.243 80 14.891
Total 1207.082 82
VAPT2 Between Groups 8.046 2 4.023 .248 .781
Within Groups 1295.795 80 16.197
Total 1303.842 82
116
Table B.9 Non-Significant Post-Treatment Horizontal Soft Tissue
Measures
N Mean
Std.
Deviation
Std.
Error
APPRN2 1.00 21 102.4810 6.33653 1.38274
2.00 29 103.0793 6.75470 1.25432
3.00 33 99.3212 6.74939 1.17492
Total 83 101.4337 6.79591 .74595
APSBN2 1.00 21 87.0762 5.70578 1.24510
2.00 29 87.0207 5.91574 1.09853
3.00 33 83.5636 6.99526 1.21772
Total 83 85.6602 6.47483 .71070
APPOG2 1.00 21 75.3333 9.51212 2.07571
2.00 29 72.8483 9.25398 1.71842
3.00 33 69.3909 10.77284 1.87531
Total 83 72.1024 10.12069 1.11089
Table B.10 ANOVA for Non-Significant Post Treatment Horizontal Soft
Tissue Measures
Sum of
Squares df Mean Square F Sig.
APPRN2 Between Groups 248.830 2 124.415 2.813 .066
Within Groups 3538.295 80 44.229
Total 3787.126 82
APSBN2 Between Groups 240.837 2 120.418 3.013 .055
Within Groups 3196.882 80 39.961
Total 3437.719 82
APPOG2 Between Groups 477.973 2 238.987 2.414 .096
Within Groups 7921.146 80 99.014
Total 8399.120 82
117
Table B.11 Post-Treatment Vertical Soft Tissue Measures: Descriptive
Statistics
N Mean
Std.
Deviation
Std.
Error
VPRN1 1.00 21 37.4381 4.44032 .96896
2.00 29 40.1310 5.91488 1.09837
3.00 33 40.7030 5.08604 .88537
Total 83 39.6771 5.35073 .58732
VSBN1 1.00 21 50.5952 4.08295 .89097
2.00 29 53.1069 4.81426 .89399
3.00 33 52.4242 4.90510 .85387
Total 83 52.2000 4.72652 .51880
VLABSU1 1.00 21 64.6952 5.44495 1.18819
2.00 29 67.1586 6.56166 1.21847
3.00 33 66.9152 4.84033 .84259
Total 83 66.4386 5.66824 .62217
VSTMSU1 1.00 21 73.4619 6.72588 1.46771
2.00 29 74.8207 6.05837 1.12501
3.00 33 74.0848 5.00132 .87062
Total 83 74.1843 5.79730 .63634
VSTINF1 1.00 21 74.6619 6.62982 1.44674
2.00 29 75.8034 5.66969 1.05283
3.00 33 75.6121 5.23311 .91097
Total 83 75.4386 5.70945 .62669
VLABIN1 1.00 21 82.6143 9.11210 1.98842
2.00 29 83.3828 6.53917 1.21429
3.00 33 83.0394 6.40561 1.11507
Total 83 83.0518 7.13812 .78351
VPOG1 1.00 21 106.2333 8.96874 1.95714
2.00 29 108.1103 9.40351 1.74619
3.00 33 104.9970 7.09976 1.23591
Total 83 106.3976 8.44500 .92696
118
Table B.12 ANOVA for Post-treatment Vertical Measures for Soft Tissue
Landmarks
Sum of
Squares df Mean Square F Sig.
VPRN1 Between Groups 145.985 2 72.993 2.652 .077
Within Groups 2201.701 80 27.521
Total 2347.687 82
VSBN1 Between Groups 79.591 2 39.796 1.817 .169
Within Groups 1752.289 80 21.904
Total 1831.880 82
VLABSU1 Between Groups 86.354 2 43.177 1.356 .264
Within Groups 2548.222 80 31.853
Total 2634.577 82
VSTMSU1 Between Groups 23.030 2 11.515 .337 .715
Within Groups 2732.880 80 34.161
Total 2755.910 82
VSTINF1 Between Groups 17.522 2 8.761 .264 .769
Within Groups 2655.494 80 33.194
Total 2673.017 82
VLABIN1 Between Groups 7.201 2 3.601 .069 .933
Within Groups 4170.926 80 52.137
Total 4178.127 82
VPOG1 Between Groups 150.376 2 75.188 1.056 .353
Within Groups 5697.703 80 71.221
Total 5848.080 82
119
Table B.13 Post-treatment Horizontal Dental Measures: Descriptive
Statistics
N Mean
Std.
Deviation
Std.
Error
APU6DCUSP2 1.00 21 32.1667 6.27275 1.36883
2.00 29 31.7414 6.04380 1.12231
3.00 33 29.6455 5.80108 1.00984
Total 83 31.0157 6.04016 .66299
APANTFOP2 1.00 21 73.3190 8.07172 1.76139
2.00 29 71.4517 6.46720 1.20093
3.00 33 68.5333 8.27023 1.43966
Total 83 70.7639 7.79137 .85521
APU6APEX2 1.00 21 44.9905 5.20537 1.13591
2.00 29 43.7379 6.10248 1.13320
3.00 33 41.8515 5.40758 .94134
Total 83 43.3048 5.69038 .62460
APL6APEX2 1.00 21 34.0571 7.70302 1.68094
2.00 29 33.3828 7.57265 1.40621
3.00 33 30.6091 7.69766 1.33999
Total 83 32.4506 7.71428 .84675
APL6TIP2 1.00 21 43.3143 6.33208 1.38177
2.00 29 42.2414 6.02213 1.11828
3.00 33 39.9727 6.66681 1.16054
Total 83 41.6108 6.43983 .70686
APU1TIP2 1.00 21 73.2381 8.05341 1.75740
2.00 29 71.1690 6.79170 1.26119
3.00 33 68.4182 8.09955 1.40995
Total 83 70.5988 7.80918 .85717
APU1APEX2 1.00 21 62.4286 5.82024 1.27008
2.00 29 62.1276 5.53172 1.02721
3.00 33 60.0848 5.81711 1.01263
Total 83 61.3916 5.75070 .63122
APL1TIP2 1.00 21 70.8286 8.21238 1.79209
2.00 29 69.0966 6.53313 1.21317
3.00 33 65.8545 7.85136 1.36675
Total 83 68.2458 7.70360 .84558
APL1APEX2 1.00 21 56.3619 9.29481 2.02829
2.00 29 54.4276 7.33007 1.36116
3.00 33 51.0303 9.13809 1.59074
Total 83 53.5663 8.76685 .96229
120
Table B.14 ANOVA for Post-Treatment Horizontal Dental Measures
Sum of
Squares df Mean Square F Sig.
APU6DCUSP2 Between Groups 105.051 2 52.525 1.456 .239
Within Groups 2886.599 80 36.082
Total 2991.650 82
APANTFOP2 Between Groups 315.013 2 157.507 2.702 .073
Within Groups 4662.838 80 58.285
Total 4977.852 82
APU6APEX2 Between Groups 134.809 2 67.405 2.139 .124
Within Groups 2520.389 80 31.505
Total 2655.198 82
APL6APEX2 Between Groups 191.307 2 95.654 1.632 .202
Within Groups 4688.520 80 58.607
Total 4879.827 82
APL6TIP2 Between Groups 161.019 2 80.509 1.988 .144
Within Groups 3239.642 80 40.496
Total 3400.660 82
APU1TIP2 Between Groups 312.629 2 156.315 2.667 .076
Within Groups 4688.001 80 58.600
Total 5000.630 82
APU1APEX2 Between Groups 94.641 2 47.320 1.446 .241
Within Groups 2617.143 80 32.714
Total 2711.784 82
APL1TIP2 Between Groups 349.772 2 174.886 3.098 .051
Within Groups 4516.554 80 56.457
Total 4866.326 82
APL1APEX2 Between Groups 397.868 2 198.934 2.695 .074
Within Groups 5904.457 80 73.806
Total 6302.326 82
121
Table B.15 Post-Treatment Vertical Dental Measures: Descriptive
Statistics
N Mean
Std.
Deviation
Std.
Error
VU6DCUSP2 1.00 21 71.7381 6.82975 1.49037
2.00 29 71.5069 5.29305 .98289
3.00 33 71.0909 4.49481 .78245
Total 83 71.4000 5.37583 .59007
VANTFOP2 1.00 21 82.1524 6.11953 1.33539
2.00 29 80.5793 5.73127 1.06427
3.00 33 82.2818 5.14177 .89507
Total 83 81.6542 5.59445 .61407
VU6APEX2 1.00 21 53.5000 6.21651 1.35655
2.00 29 53.1345 5.82803 1.08224
3.00 33 53.6485 4.38906 .76404
Total 83 53.4313 5.34721 .58693
VL6APEX2 1.00 21 95.4857 7.60752 1.66010
2.00 29 93.7966 5.86092 1.08834
3.00 33 93.6636 5.61103 .97675
Total 83 94.1711 6.22312 .68308
VU6TIP2 1.00 21 74.3286 6.51591 1.42189
2.00 29 73.6690 5.37096 .99736
3.00 33 73.5909 4.51362 .78572
Total 83 73.8048 5.31519 .58342
VL6TIP2 1.00 21 74.9143 6.61901 1.44439
2.00 29 74.0828 5.48433 1.01842
3.00 33 74.3121 4.53299 .78909
Total 83 74.3843 5.39269 .59192
VU1TIP2 1.00 21 81.8476 6.46256 1.41025
2.00 29 81.2172 5.20364 .96629
3.00 33 82.0909 5.01955 .87379
Total 83 81.7241 5.42347 .59530
VU1APEX2 1.00 21 55.3381 5.54125 1.20920
2.00 29 55.5517 4.35313 .80836
3.00 33 57.5879 4.85391 .84496
Total 83 56.3072 4.92509 .54060
VL1TIP2 1.00 21 79.9762 6.43358 1.40392
2.00 29 79.7690 5.17060 .96016
3.00 33 80.1758 4.57705 .79676
Total 83 79.9831 5.23745 .57489
VL1APEX2 1.00 21 99.6381 7.82461 1.70747
2.00 29 98.3862 6.54658 1.21567
3.00 33 97.5273 5.54258 .96484
Total 83 98.3614 6.50024 .71349
122
Table B.16 ANOVA for Post-Treatment Vertical Dental Measures
Sum of
Squares df Mean Square F Sig.
VU6DCUSP2 Between Groups 5.885 2 2.942 .100 .905
Within Groups 2363.875 80 29.548
Total 2369.760 82
VANTFOP2 Between Groups 51.717 2 25.858 .823 .443
Within Groups 2514.709 80 31.434
Total 2566.426 82
VU6APEX2 Between Groups 4.211 2 2.105 .072 .931
Within Groups 2340.388 80 29.255
Total 2344.599 82
VL6APEX2 Between Groups 48.859 2 24.429 .625 .538
Within Groups 3126.772 80 39.085
Total 3175.631 82
VU6TIP2 Between Groups 7.806 2 3.903 .135 .874
Within Groups 2308.792 80 28.860
Total 2316.598 82
VL6TIP2 Between Groups 8.707 2 4.354 .147 .864
Within Groups 2375.942 80 29.699
Total 2384.650 82
VU1TIP2 Between Groups 12.211 2 6.105 .204 .816
Within Groups 2399.741 80 29.997
Total 2411.952 82
VU1APEX2 Between Groups 90.399 2 45.199 1.904 .156
Within Groups 1898.637 80 23.733
Total 1989.036 82
VL1TIP2 Between Groups 2.556 2 1.278 .045 .956
Within Groups 2246.781 80 28.085
Total 2249.336 82
VL1APEX2 Between Groups 57.207 2 28.604 .672 .514
Within Groups 3407.549 80 42.594
Total 3464.757 82
123
Literature Cited
1. Ker AJ, Chan R, Fields HW, Beck M, Rosenstiel S.
Esthetics and smile characteristics from the layperson's
perspective: a computer-based survey study. J Am Dent
Assoc. 2008;139(10):1318-1327.
2. Van der Geld P, Oosterveld P, Van Heck G, Kuijpers-
Jagtman AM. Smile attractiveness. Self-perception and
influence on personality. Angle Orthod. 2007;77(5):759-
765.
3. Peck S, Peck L, Kataja M. The gingival smile line. Angle
Orthod. 1992;62(2):91-100.
4. Tjan AH, Miller GD, The JG. Some esthetic factors in a
smile. J Prosthet Dent. 1984;51(1):24-28.
5. Vig RG, Brundo GC. The kinetics of anterior tooth
display. J Prosthet Dent. 1978;39(5):502-504.
6. Van der Geld PA, van Waas MA. [The smile line, a
literature search]. Ned Tijdschr Tandheelkd.
2003;110(9):350-354.
7. Schendel SA, Eisenfeld J, Bell WH, Epker BN, Mishelevich
DJ. The long face syndrome: vertical maxillary excess.
Am J Orthod. Dentofacial Orthop. 1976;70(4):398-408.
8. Singer R. A study of the morphologic, treatment and
esthetic aspects of gingival display. American Journal
of Orthod. Dentofacial Orthop. 1974;65:435-436.
9. Mackley RJ. An Evaluation of smiles before and after
orthodontic treatment. The Angle Orthod. 1993;63(3):183-
189.
124
VITA AUCTORIS
Jessica H. Cox was born in Pocahontas, Arkansas on
October 24, 1981 to Danny B. Holt, M.D. and Sandra F. Holt.
She is the second of four children.
She grew up in Pocahontas, Arkansas and graduated from
Pocahontas High School in May of 2000. She attended the
University of Mississippi in Oxford, Mississippi where she
obtained a Bachelor of Science degree in 2004. She obtained
her Doctor of Dental Surgery degree from the University of
Tennessee in May of 2007. In June of that same year, she
began her postgraduate orthodontic residency at Saint Louis
University, Center for Advanced Dental Education, where she
expects to receive a Master’s of Science in Dentistry in
Orthodontics in January 2010.
Jessica met her husband, Wynne, while attending the
University of Mississippi. They were married on June 17,
2006. Upon graduation, they plan to move to Hernando,
Mississippi where Jessica will start a private orthodontic
practice.