Download A LONGITUDINAL CEPHALOMETRIC STUDY EVALUATING THE SOFT

A LONGITUDINAL CEPHALOMETRIC STUDY EVALUATING THE SOFT
TISSUE PROFILES OF PATIENTS TREATED WITH EXTRACTION
MECHANICS 25 YEARS POST-TREATMENT
Anita N. Bhavnani, D.M.D.
An Abstract Presented to the Graduate Faculty of
Saint Louis University in Partial Fulfillment
of the Requirements for the Degree of
Master of Science in Dentistry (Research)
2012
ABSTRACT
Introduction: Controversy exists in literature regarding facial esthetics with
extraction and non-extraction treatment. Purpose: The purpose of this study is to
provide an evidence-based answer to the question: whether or not the extraction of
premolars during orthodontic treatment will improve or harm the esthetics of the resulting
soft tissue facial profile. This longitudinal study investigates changes in the soft tissue
profile after treatment and again 25+ years later. Methods: Cephalometric films were
traced on a sample of 57 untreated individuals and a sample of 47 individuals treated with
extractions. The mean ages of the untreated sample were 16 years 0 months and 56 years
and 8 months respectively and were matched to the mean ages of an extraction treated
sample, 15 years 11 months and 39 years and 4 months respectively. Descriptive
statistics were collected and individual t-tests were performed for the purpose of
comparison and contrast. Results: The results show that without treatment, the soft
tissue profile generally changes in a downward and forward manner. With extraction
treatment, the downward change which would otherwise happen due to growth is less and
the soft tissue change is mainly forward. This study also shows that the soft tissue
profiles 25+ years post treatment for both the untreated and extraction treated samples are
similar and considered esthetically acceptable. Conclusions: 1) There is no substantive
esthetic difference between the untreated and extraction treated samples. 2) There are
important different directional changes for the soft tissue profiles of untreated and
extraction treated individuals. 3) The changes for the untreated sample are greatest for
the lips and chin and change in a downward and forward direction. 4) The changes for
the extraction treated sample are generally greatest for the lips and chin and change in a
1
forward direction. 5) The results from this study are significant to orthodontics as a
dental specialty and can be used as a treatment planning aid in an effort to positively
direct soft tissue changes. 6) Extractions do not harm the esthetics of the resulting soft
tissue facial profile over time.
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A LONGITUDINAL CEPHALOMETRIC STUDY EVALUATING THE SOFT
TISSUE PROFILES OF PATIENTS TREATED WITH EXTRACTION
MECHANICS 25 YEARS POST-TREATMENT
Anita N. Bhavnani, D.M.D.
A Thesis Presented to the Graduate Faculty of
Saint Louis University in Partial Fulfillment
of the Requirements for the Degree of
Master of Science in Dentistry (Research)
2012
COMMITTEE IN CHARGE OF CANDIDACY:
Professor Eustaquio A. Araujo,
Chairperson and Advisor
Professor Rolf G. Behrents
Associate Clinical Professor Donald R. Oliver
i
DEDICATION
To my mother and father, for giving me the means necessary to make my dreams
come true. Every success in my life is a product of your unconditional love and constant
support. I will never be able to thank you enough.
ii
ACKNOWLEDGEMENTS
Firstly, thank you Dr. Araujo for your enormous amount of encouragement and
direction. You have gone above and beyond your duties from the very beginning and I
appreciate all that you have done.
Dr. Behrents, thank you for your guidance and wisdom. I feel fortunate to have
learned firsthand from you. Thank you for teaching me how to evaluate cephalometric
films and more importantly how to put ideas together. This thesis would not have been
possible without you.
Dr. Oliver, thank you for your vast knowledge and thoughtful consideration.
Your positive attitude and attention to detail were vital for this thesis.
Lastly, thank you Dr. Vaden and those who contributed to the Bolton Study. This
project would not be feasible without the long term records you provided.
iii
TABLE OF CONTENTS
List of Tables ..................................................................................................................... vi
List of Figures .................................................................................................................. viii
CHAPTER 1: INTRODUCTION
Description of the problem ......................................................................................1
CHAPTER 2: REVIEW OF THE LITERATURE
History......................................................................................................................2
Review of Past Studies.............................................................................................9
General Soft Tissue Profile Angles..........................................................................9
Growth Studies ...................................................................................9
Extraction Studies .............................................................................12
Soft Tissue Thickness ............................................................................................13
Growth Studies..................................................................................13
Extraction Studies .............................................................................15
Lip Changes ...........................................................................................................15
Growth Studies..................................................................................15
Extraction Studies .............................................................................18
The Soft and Hard Tissue of the Nose .......................................................20
Growth Studies..................................................................................20
Extraction Studies .............................................................................22
Chin Changes .............................................................................................22
Growth Studies..................................................................................22
Extraction Studies .............................................................................22
Summary and Purpose ...........................................................................................24
References ..............................................................................................................25
CHAPTER 3: JOURNAL ARTICLE
Abstract ..................................................................................................................28
Literature Review...................................................................................................30
Materials and Methods ...........................................................................................32
Untreated Sample ..............................................................................32
Treated Sample .................................................................................32
Analysis.............................................................................................33
Results ....................................................................................................................36
Sample...............................................................................................36
Untreated and Extraction Treated Results ........................................36
Untreated and Extraction Treated Differences .................................39
Discussion ..............................................................................................................46
Comparison with Past Studies ..........................................................46
Analysis of Untreated and Extraction Treated Sample .....................48
Clinical Relevance of the Present Study ...........................................51
Conclusions ............................................................................................................53
Literature Cited ......................................................................................................54
iv
Appendix A Detailed Literature Review ...........................................................................57
Appendix B Landmarks .....................................................................................................60
Appendix C Independent t-Test Results ............................................................................62
Vita Auctoris ......................................................................................................................69
v
LIST OF TABLES
Table 2.1. General Soft Tissue Profile Changes ..................................................................9
Table 2.2. Soft Tissue Thickness Changes ........................................................................14
Table 2.3. Lip Changes ......................................................................................................16
Table 2.4. Nasal Changes...................................................................................................21
Table 2.5. Chin Changes ....................................................................................................22
Table 3.1. Ages of Untreated Sample ................................................................................36
Table 3.2. Ages of Extraction Sample ...............................................................................36
Table 3.3. Comparison of Landmark Differences .............................................................40
Table 3.4. Comparison of Facial Measurement Differences .............................................42
Table 3.5. Comparison of Soft Tissue Thickness Differences...........................................42
Table 3.6. Comparison of Soft Tissue Length Differences ...............................................42
Table 3.7. Large, Medium and Small Changes ..................................................................44
Table A.1. Details for Growth Studies...............................................................................57
Table A.2. Details for Extraction Studies ..........................................................................58
Table B.1. Landmarks and Definitions ..............................................................................60
Table B.2. Abbreviations and Measurements ....................................................................61
Table C.1. Comparison of T2 Landmarks .........................................................................63
Table C.2. Comparison of T2 Facial Measurements .........................................................64
Table C.3. Comparison of T2 Soft Tissue Thickness ........................................................65
Table C.4. Comparison of T2 Soft Tissue Length .............................................................65
Table C.5. Comparison of T3 Landmarks .........................................................................66
Table C.6. Comparison of T3 Facial Measurements .........................................................67
vi
Table C.7. Comparison of T3 Soft Tissue Thickness ........................................................68
Table C.8. Comparison of T3 Soft Tissue Length .............................................................68
vii
LIST OF FIGURES
Figure 2.1. The Tweed Triangle ..........................................................................................6
Figure 2.2. E-Plane and H-Line ...........................................................................................8
Figure 3.1. Reference Planes .............................................................................................33
Figure 3.2. Landmarks for Analysis ..................................................................................34
Figure 3.3. Post Treatment Landmark Results...................................................................38
Figure 3.4. 25+ Post Treatment Landmark Results ...........................................................39
Figure 3.5. Changes from T2 to T3 for Both Samples.......................................................43
Figure 3.6. Ricketts’ E-plane for Both Samples at T2 .......................................................49
Figure 3.7. Ricketts’ E-plane for Both Samples at T3 .......................................................50
Figure 3.8. Lip and Chin Changes from T2 to T3 for Both Samples ................................51
viii
CHAPTER 1: INTRODUCTION
Description of the Problem
Before orthodontics was defined as a dental specialty, there was little
consideration of the effects of correcting dental irregularities on the soft tissue profile of
the face. Facial esthetics was not directly correlated to the occlusion and teeth. Times
have changed, not only in the sense that there is recognition of a relationship between
facial esthetics and orthodontic treatment, but also that patients are now more involved in
selecting their treatment options and have the ability to make choices once educated by
their orthodontist.
A century has passed since the birth of orthodontics as a recognized specialty and
it is a common counter-point during patient consultation for a patient to oppose, and at
times refuse, treatment plans that include the extraction of bicuspids. This negative
response stems from not only the fear of the physical removal of the teeth but also from
the long standing notion that taking out teeth can “flatten” and therefore compromise the
esthetics of the face.
It is the job of orthodontists to educate patients and justify the reasons for
extraction in specific cases. Along these same lines, it is their duty to create treatment
plans based on evidentiary facts that reveal the full effects of extraction on the soft tissue
profile. It would be helpful, therefore, to determine if any facial soft tissue profile
changes occur and to determine which are due to extractions apart from normal growth
and aging.
1
CHAPTER 2: REVIEW OF THE LITERATURE
History
Although orthodontics is a dental specialty that has seen drastic changes from its
birth to the present there is one common aspect that has maintained itself throughout the
century – a strong emphasis on facial esthetics. Value was placed on esthetics long
before the establishment of orthodontics as a specialty as emphasized by Peck and Peck.1
Esthetics has evolved over the years and in written history dates back to 5,000 years ago
when the Egyptians documented their attitudes towards esthetics in art. The Egyptians
were concerned with beauty, harmony and proportion and these same principles have
made their way through to present day orthodontics.
For the Greeks, the art of sculpture peaked much earlier around 4 and 5 B.C.,
often called the start of the Golden Ages. The Greeks showed harmonious anatomic
relationships in sculptures and historically exemplified the Grecian esthetic ideals in a
sculpture of Aphrodite of Melos. It was not until many centuries later, that Plato noted
harmony as a result of proportions and assumed that these proportions were fixed
quantities. Later, the Romans conquered the Greeks and though the Golden Ages
continued for a short while, these prosperous times soon came to an end as the Dark Ages
began. The Romans nearly abolished idealism with their true-to-life sculptures; they
described beauty as natural rather than ideal. Idyllic beauty was condemned to be pagan
and mythical during the Dark and Middle ages and beauty in proportion was suppressed.1
During the Renaissance in Italy, Michelangelo recreated proportional faces and
exemplified this in his famous sculpture of David. As the 16th century began, Firenzuola
an Italian author unknowingly generated a trend of detailing human facial beauty in
2
writing. For the next three centuries authors described facial beauty passionately in their
writings. It was Woolnoth in 1865 from Britain who first classified profiles as straight,
convex or concave and astutely created relationships with these classifications: the
straight face is considered handsomest, convex faces retain youthful appearance while
concave faces bring the face to maturity too soon.1
In 1880, the Father of Orthodontia, Kingsley, published the first textbook on
scientific treatment of irregularities of teeth titled Treatise on Oral Deformities as a
Branch of Mechanical Surgery. While this textbook concentrated on etiology, diagnosis
and treatment techniques,2 Kingsley incorporated esthetics into orthodontics and kept the
final treatment outcome in mind.
Angle, considered the Father of Modern Orthodontics, formally established
orthodontics as a specialty in 1900 when he founded the Angle School of Orthodontia in
St. Louis, Missouri.3 Angle was the author of a series of books and in Chapter 3 of
Treatment of Malocclusion of the Teeth. Angle’s System (Seventh Edition) he asserted
that orthodontia was closely connected with facial esthetics.4 Angle, from the beginning,
emphasized occlusion and although he placed value on esthetics, he believed that optimal
facial esthetics would continuously coincide with ideal occlusion.5 This claim led Angle
and his followers to strive solely for ideal occlusion with the misled notion that ideal
esthetics would follow.
Tweed, Angle’s student and originally one of his followers, challenged Angle on
esthetic grounds and determined that normal occlusion does not always result in ideal
facial balance.4 Tweed developed new treatment objectives placing balance of harmony
and facial lines, stability of the denture, healthy mouth tissues and an efficient chewing
3
mechanism as respective priorities.4 While Angle insisted that patients who maintain
their full complement of teeth will have superior occlusion and therefore esthetics, Tweed
recognized through cephalometrics the impossibility of attaining balance and facial
harmony when orthodontically treating all patients without extraction. Tweed noticed
that in some cases of non-extraction treatment that the teeth and the therefore covering
soft tissue became too protrusive and were not esthetic.
It was in 1931 when Broadbent introduced cephalometric radiography at the
Bolton Study in Cleveland, Ohio.6 The new x-ray technique was an ideal method to
measure changes in facial profile for both hard and soft tissue in relation to the rest of the
head. This historic advance had direct application to orthodontics and was a
revolutionary diagnostic instrument, a sound technique to monitor growth, and a tool to
evaluate treatment. Cephalometrics was perceptively described at the time as a tool that
tells “the story of tissue responses, body changes and sometimes changes of muscle
function.”7
In 1940, Tweed collected a sample of 100 patients first treated without extractions
and later retreated with extractions.8 He displayed models and cephalometric records at a
meeting of the American Association of Orthodontists and launched one of orthodontic’s
greatest controversies: extraction versus non-extraction treatment. The answer to the
controversy of extraction versus non-extraction treatment became dependent on facial
esthetics as first pointed out by Tweed – if a patient does not have extractions will their
profile become too protrusive? Conversely, if the patient has extractions, will their facial
profile become flat? Before these questions could be answered, normal values for the
soft tissue profile needed to be determined and more so, a uniform method for
4
measurement was necessary. Cephalometric records were the answer representing a
straightforward technique to measure standardized values among samples.
Esthetics, at this point in orthodontics, was defined by profile enhancement rather
than ideal occlusion. A mass effort was made to establish a definition of beauty,
harmony and proportion in the facial profile. To this end, between 1937 and 1969, at
least thirty five separate studies were published in orthodontic journals aiming to describe
“normal” dentofacial, craniofacial and soft tissue relationships.1 A relatively early study
in 1948 by Downs, although based on a small sample size, revealed “norms” that were
comparable to those reported by others, at later dates, with larger samples.6
It was not long before orthodontists were directly applying cephalometrics to
orthodontic diagnosis and treatment planning in order to achieve ideal facial profile
esthetics.9 It was recognized that between the hard tissue profile and the soft tissue
profile, the soft tissue profile was of greater importance when considering esthetics.10 It
had also been recognized by this time the nose, lips, and chin play a dominant role in
facial esthetics.11 These three structures define the soft tissue facial profile and are
important to consider when studying the face. The nose and chin were found to be, in
most cases, independent of orthodontic treatment and affected solely by growth while it
was found the lips could be modified with orthodontics.10,12-13
In 1959, Steiner used cephalometrics to create clinical guidelines that could be
adapted for each individual patient.14 He created a cephalometric appraisal chart that
included average cephalometric values and presented possible arrangements of teeth with
various plausible apical base relationship scenarios.7 He used cephalometrics to help
make decisions not only for when to extract but also which teeth to extract.14
5
Tweed too developed with his own norms and cephalometric analysis in 1954.15
He conducted a study with a sample selected on the basis of subjective facial esthetics;
occlusion was not considered. He derived norms from his sample that had “pleasing
faces” for Frankfort Mandibular Plane Angle (FMA), Incisor Mandibular Plane Angle
(IMPA) and Frankfort Mandibular Incisor Angle (FMIA);15 these lines form the “Tweed
Triangle (Figure 2.1).” This triangle is still used today as a treatment planning aid. Each
angle can be manipulated in orthodontics to achieve the ideal values; the ideal FMA is
250, the ideal IMPA is 900, and the ideal FMIA is 650.15
Figure 2.1. The Tweed Triangle (Modified From Tweed)16
Although more recent investigations have been performed, many orthodontists
still evaluate the need for extraction in balance with ideal facial esthetics using Tweed’s
original beliefs. It is likely that Tweed’s manner of practice has continued into the
present era because he was the first to recognize the delicate relationship between
occlusion and facial esthetics. The two are intimately connected, whether normal or
6
abnormal they remain interrelated.17 From his study of normal faces, Tweed learned that
in cases with ideal facial esthetics, the lower incisors were upright over basal bone at a
right angle to the mandibular plane.17 He believed tooth irregularity was a consequence
of discrepancy between tooth arrangement and basal bone in relation to lack of osseous
growth.17 He noted arch length, more specifically mandibular arch length, was
determined by the mandibular first molars that erupt around age 6 and only naturally
move a few millimeters as other teeth erupt into the arch. Tweed did not believe the
mandible grew as the result of orthodontic treatment. Therefore, when a large
discrepancy existed, he believed extraction treatment was the only way to correctly align
teeth in their pre-determined arch length and the incisors upright over basal bone.
Ricketts in 1964 noticed that there was an average tendency toward lower incisor
retraction with growth and maturation.18 He also took note of the effect of the chin and
point B on incisor position and deemed all three together formed the “Keystone Triad;”
he set treatment goals accordingly. He took into consideration the growth of the chin
including both the forward thrust from the condyle and ramus with the local alteration in
shape in contour of the symphysis by remodeling resorption.18 Ricketts defined a line
from the nose to the chin as the Esthetic plane or “E-plane” and claimed that most people
have an aversion to lips that protrude past this plane (Figure 2.2).11 He claimed the upper
lip should be related to the lower lip and the lower lip should be considered the main
reference. He believed the ideal adult lower lip should be located 4 mm behind the Eplane +/- 3 mm.11
7
Figure 2.2. E-plane (solid line) and H-Line (dotted line)
Eleven parameters were isolated by Holdaway in 1983 in his cephalometric
analysis.19 He used these parameters and found fundamental similarities in terms of
beauty. In his analysis, he created and defined the H-line which extends from soft tissue
pogonion to the vermillion border of the upper lip (Figure 2.2).20 Of his eleven
parameters, some were directly affected by orthodontics. They included an H angle that
was within 1-20 of the average for the convexity measurement of the individual. Also, a
defined curl or form to the upper lip measuring across the range of 4-6 mm in the depth
of the superior sulcus to the H-line and from 2.5 mm to 4 mm to a perpendicular line
drawn from Frankfort Horizontal. The last parameter affected by orthodontics was the
lower lip location, ideally it should be either on the H-line or within 1 mm of it.19
8
Review of Past Studies
General Soft Tissue Profile Angles
Growth Studies
In 1959, Burstone deemed appearance to be the primary function of the face and
sought to develop a method to measure the soft tissue profile and determine the
characteristics of good or acceptable faces.12 He applied his own method of the
integumental extension analysis and was able to determine the facial soft tissue changes
that take place without treatment. Burstone found that the convexity of the profile
decreased without the consideration of the nose (Table 2.1).10
Table 2.1. General Soft Tissue Profile Changes in Untreated Patients and Patients Treated
with Extractions
Convexity of the
Facial Profile Angle
Nasolabial Angle
Mentolabial Angle
Anterior Face
Height
Untreated
Decrease with maturation.10, 21-22
Without considering nose there
is a decrease10, 21, 23 however
with nose there is an increase in
convexity23-24
Decreases with age22
Increases with age22, 29
Increases, some say more in
upper face22 while other claim
mostly in lower29, 30-31
Treated Extraction
Decrease25-27
Increases with treatment if
the teeth retracted, but highly
variable28
Variable results28
Increases32
That same year, Subtelny conducted a longitudinal study involving the soft tissue
facial structures and their profile characteristics.21 Subtelny recognized that the hard
tissue and soft tissue do not have a direct relationship due to the variation of the thickness
of the soft tissue covering the face. Subtelny found similar results to those of Burstone
9
and agreed that the convexity of the profile decreased without the consideration of the
nose (Table 2.1).21
In 1984, Behrents reported on a recall study involving individuals from the
original Bolton Study.22 Behrents aimed to discover the soft tissue profile changes that
continued to occur without treatment into late adulthood. He found that “growth as
defined continues… [and] ceases perhaps only at death.”22 He also found that growth of
the soft tissue profile components was greater than the skeletal components. Behrents
agreed with Burstone and Subtelny that with age the convexity of the profile decreased
(Table 2.1). Behrents also found that the nasolabial angle became more acute with age,
the mentolabial angle increased with age, and that the anterior face height increased with
age. Regarding the anterior face height, Behrents found that this increase was mostly in
the upper face.22
A year later, Bishara and his colleagues compared three different cephalometric
analyses involving six specific soft tissue profile parameters and compared the results.23
Bishara et al. found that in order to properly evaluate the soft tissue profile, a number of
soft tissue parameters were needed. Bishara et al. found that without consideration of
the nose, there was a decrease in facial convexity but opposed to Burstone and Subtelny
they found an increase in facial convexity when considering the soft tissue nose (Table
2.1).23
In 1995, Choconas and Bartroff wanted to take the idea of mean facial profile
changes a step further and tried to predict soft tissue facial profile changes. During their
study they found a similar increase in facial convexity when considering the soft tissue
nose as Bishara et al. found (Table 2.1).24
10
In 1994, Formby along with Nanda and Currier conducted a longitudinal study to
evaluate changes in the adult facial profile. Formby agreed with Behrents that with age,
the mentolabial angle and the anterior face height both increased (Table 2.1). Formby,
however, found that with the increase in anterior face height, there was a larger increase
in the lower face rather than the upper.29
In 1979, Forsberg conducted a study evaluating facial morphology and aging
using longitudinal cephalometric x-rays. Even though Forsberg studied more skeletal
landmarks than soft tissue points, he still noted significant soft tissue changes. Forsberg
found similar results to Formby et al. and although he agreed with Behrents that there
was an increase in the anterior face height, he found similar results to Formby et al., that
the increase was greater in the lower face (Table 2.1).30
Sarnas and Solow also sought answers to early adult changes in the skeletal and
soft tissue profile in 1980. Sarnas et al. found similar significant skeletal and soft tissue
changes that occurred with growth alone for both males and females.31 Sarnas et al.
found similar results to Formby et al. and Forsberg, and although they agree with
Behrents that there is an increase in the anterior face height, they found similar results to
Formby et al. and Forsberg that the increase was greater in the lower face (Table 2.1).31
11
Extraction Studies
Paquette and a group of his colleagues compared non-extraction treatment with
premolar extraction treatment in 1992. All of the cases were considered “borderline” and
the decision to extract was based on profile convexity, anterior protrusion, and
crowding.25 Although they found that premolar extraction does decrease the angle of
convexity of the facial profile (Table 2.1), they did not find that it “flattened the
profile…enough to ruin the face.”25
In 1973, Anderson, Joondeph and Turpin investigated not only the orthodontic
effects of extraction along with growth but also re-evaluated the soft tissue profiles 10
years after treatment was completed. Overall, they noticed a reduction of procumbancy
in the lips and similar to Paquette et al., found a decrease in the convexity of the facial
profile; this involved relative retrustion of the teeth and lips (Table 2.1). They also noted
that this “flattening” continued to the 10 year post treatment point.26
In 2000, Bowman and Johnston studied the esthetic impact of extraction and nonextraction treatment using Caucasian patients. It was concluded that extraction treatment
could produce improved facial esthetics if the lips protruded more than 2-3 mm behind
the Ricketts E-plane. They suggested that if the objective was to reduce lip
procumbency, extraction treatment would produce positive results.27 Therefore, Bowman
and Johnston agree with Paquette et al. and Anderson et al. that extractions decreased
convexity of the soft tissue profile (Table 2.1).27
In 1989, Drobocky and Smith collaborated in an attempt to isolate the changes in
the soft tissue profile due solely to treatment. Drobocky et al. found that the results
obtained with treatment compared well with “normal ideal facial esthetics” and only 4%
12
of the extraction cases showed excessively retruded teeth and therefore excessively flat
profiles.28 When evaluating the nasolabial angle, Drobocky et al. saw an increase of the
angle with extraction treatment however they did note the results were variable (Table
2.1). Also, when evaluating the mentolabial angle, Drobocky could not come to a
conclusion as the results were too variable.28
In 1994, Binda and his coworkers evaluated not only the soft tissue profile
changes in orthodontically treated patients but more specifically those with Class II Div.
2 malocclusions.32 They saw both sagittal and vertical facial dimensional changes due to
growth and therapy. They found a large number of variables changed significantly from
the 2 year to 5 year post treatment time points and also noticed that a great deal of
individual variation exists. One significant variable they found was that with extraction
treatment, the anterior face height increased (Table 2.1).32
Soft Tissue Thickness
Growth Studies
Burstone, Subtelny and Forsberg also evaluated the soft tissue thickness of the
lips and agree that the upper lip thinned with age (Table 2.2).10, 22, 30 Subtelny studied the
lips further and pointed out that the upper lip had greater thickness at the vermillion
rather than over A point, and that the lower lip had greater thickness at the vermillion
than that over B point.13, 21 Subtelny also evaluated the soft tissue thickness of the nose
and pogonion and found that the soft tissue of the nose increased with age but to a lesser
extent than changes that were seen at A point and pogonion, and he found that the soft
tissue over pogonion increased more than the nose but less than A point.13, 21 Holdaway
13
disagreed with Subtelny and found that the soft tissue thickness over A point stayed the
same.26
Table 2.2. Soft Tissue Thickness Changes in Untreated Patients and Patients Treated with
Extractions
Lip
A point
B point
Nose
Pogonion
Untreated
Treated Extraction
Upper lip thins with
maturity10, 22, 30 and the upper lip
has greater thickness at the
vermillion than over A point.
Lower lip has greater thickness
at the vermillion than over B
point 13, 21
Some say remains the same,19
others say it increases less than
the lip vermillion but more than
pogonion and nasal
thickness13, 21 and some say it
increases more than that of the
lip vermillion33
Some say increase but to lesser
extent than lower lip at
vermillion21 while others say the
increase is more than
vermillion33
Increase but to a lesser extent
than A point and Pogonion21
Increase more than nose but to a
lesser extent than A point21
Upper lip becomes thicker26
with retraction in 1:3 ratio11
and there is no change in
lower lip26
Small increase26
No change26
Not found in literature
Increase26
Nanda et al., performed a longitudinal study in 1990 assessing growth changes in
the soft tissue profile.33 Nanda et al. not only detailed the aging of the soft tissue profile
but also noted sexual dimorphism between males and females; males showed greater soft
tissue increases over a longer period of time.33 Nanda et al. agreed with Subtelny and
found that the soft tissue over A point increased, but in contraindication with Subtelny
they found that the increase was more than that of the lip vermillion (Table 2.2).33 As
14
mentioned before, with regard to B point Subtelny saw an increase, but to a lesser extent
than the lower lip at the vermillion21 and while Nanda agreed with the increase, he found
that it was more than that of the lower lip vermillion.33
Extraction Studies
Ricketts and Anderson et al. agree that with extraction treatment the upper lip
became slightly thicker and there was a retraction of lip to teeth at a ratio of 1:3 (Table
2.2).11, 26 Anderson et al. also saw a small increase of the soft tissue over A point and
pogonion and found no change in the soft tissue over B point.26
Lip Changes
Growth Studies
Subtelny, Sarnas et al. and Nanda et al. agree that the upper lip length increased
with age and Subtelny and Sarnas et al. also found that the lower lip increased with age
(Table 2.3).21, 31, 33 Subtelny then compared the upper and lower lip and found that the
upper lip increased more than the lower lip.21 Subtelny also evaluated upper lip posture
and its vertical relationship to the underlying dento-alveolar structure and found that the
lip moved from below the incisal edge of maxillary incisors superiorly until age 9 and
then remained constant. When evaluating the lower lip posture and its vertical
relationship to the underlying dento-alveolar structures he found that the lower lip
generally remained constant covering the incisal third of the maxillary central incisors.21
15
Table 2.3. Lip Changes in Untreated Patients and Patients Treated with Extractions
Upper lip length
Lower lip length
Superior Labial
Sulcus
Untreated
Increase with age,31, 33 more so
in lower lip than upper13, 21
Increase with age,33 more than
upper lip13, 21
Moves inferiorly in relation to
subnasale10
Inferior Labial
Sulcus
Decrease with age10
Upper Lip Posture
(Vertical relation to
Dento-alveolar
Structure)
Lip moves from below the
incisal edge superiorly and then
remains constant21
Lower lip posture
(Vertical relation to
Dento-alveolar
structure)
Covers the incisal third of
maxillary central incisors21
16
Treated Extraction
No change32
No change32
Some say affected by
maxillary incisors,34 others
say moves with the maxillary
incisors and A point35 while
others say it is variable36
Some say affected by
mandibular incisors,34 others
say moves with the
mandibular incisors and B
point 35 while others say it is
variable36
Lip line is lowered32
Lip line is lowered32
Table 2.3. Lip Changes in Untreated Patients and Patients Treated with Extractions
(Continued)
AP postural
relationship of lips
to underlying
structures
Untreated
Most agree there is uprighting of
mandibular alveolar process and
the incisors with age and the
mandibular alveolar process
becomes less protrusive to the
facial plane21-22, 30, 33 but some
say the incisors flare with age29
Treated Extraction
A 1:1 ratio with tooth
movement26 however, if the
lip is very thick may not
follow.37 Some say the lower
lip follows the lower incisor
more than the upper lip
follows the upper incisor.34
Some say lingual movement
of lower lip is dependent on
U1 and L126 and ratios
include the upper incisor to
upper lip 2.9:1, the lower
incisor to lower lip 1:1 and
the upper incisor to lower lip
1:1.38 Another study found
1:3.8 lip retraction and
incisor retraction.39 Many
found the upper and lower
lip become more
retrusive25-28, 38
Burstone evaluated the superior labial sulcus and found that it moved inferiorly in
relation to subnasale with age (Table 2.3). He also studied the inferior labial sulcus and
found it to decrease with age.10
Subtelny, Behrents, Sarnas et al., and Nanda et al. agree that there was uprighting
of the mandibular alveolar process and mandibular incisors with age and that these
components became less protrusive to the facial plane (Table 2.3).21-22, 31, 33 Formby et
al., however, noted that the incisors flared with age.29
17
Extraction Studies
Binda et al. evaluated upper and lower lip length and saw no change with
extraction treatment. They also evaluated the upper and lower lip postures in vertical
relation to the underlying dento-alveolar structure and found that with extraction
treatment, the lip line was lowered (Table 2.3).32
In 1961, Bloom conducted a study evaluating perioral profile changes that
occurred with both treatment and growth.34 He responded to the controversy of whether
soft tissues directly follow the underlying skeletal structures or not. He also noted that
treatment and growth usually occur during the same time and together confound the
effects of each other.34 He reported very high correlation values and showed that the soft
tissue response is closely related to hard tissue structures that are affected by
orthodontics. He found that with extraction treatment, the maxillary incisors affected the
superior labial sulcus and the lower mandibular incisors affected the inferior labial sulcus
(Table 2.3).34
In 1972, Hershey evaluated profile changes in Caucasian females as affected by
incisor tooth retraction. Contrary to Binda et al., Hershey found that the superior labial
sulcus changed with A point and the inferior labial sulcus changed with B point (Table
2.3).35
Wholley and Woods focused on the effects that the extraction of teeth have on the
curvatures of the upper and lower lips. They found a wide range of variation for
individual lip changes in the depths of the lip curvatures. They concluded that with
careful orthodontic treatment, one could extract teeth and still protect the facial profile.
Wholley et al. neither agreed nor disagreed with Binda or Hershey and found that the
18
changes of both the superior and inferior labial sulcus were too variable to draw
significant conclusions as to the relationship between hard and soft tissues (Table 2.3).36
Anderson et al. found similar results to Holdaway and they agree that with
extraction treatment the anterior-posterior relationship of the lips to the teeth was
maintained according to a 1:1 ratio (Table 2.3).19, 26 Holdaway found, however, that if
the lips were very thick that they would not follow the teeth at all.19 Bloom further
defined the anterior-posterior relationship by finding that the lower lip follows the lower
incisor more than the upper lip follows the upper incisor.34 Anderson et al. disagree with
Bloom and found that the lingual movement of the lower lip is dependent on both the
upper and the lower incisors rather than the lower incisor alone.26
In 1964, Rudee investigated the soft tissue facial changes resulting from
extraction orthodontic therapy.38 He aimed to create a prediction scheme for expected lip
retraction. In doing so, he correlated the upper and lower lip movement relative to upper
and lower incisor movements. Rudee found that the upper lip moved with the upper
incisor at a 1:2.9 ratio, the lower lip moved with the lower incisor at a 1:1 ratio, and the
upper lip moved with the lower incisor according to a 1:1 ratio (Table 2.3).38
In 1982, Waldman concentrated mostly on changes of lip contour that occurred in
response to orthodontic treatment, more specifically incisor retraction. His results
showed a 1:3.8 ratio of lip retraction with incisor retraction (Table 2.3).39 Paquette et al.,
Bowman et al., Anderson et al., Drobocky et al., Rudee and Waldman all agree that the
upper and lower lips became more retrusive with extraction treatment (Table 2.3).25-28, 3839
19
The Soft and Hard Tissue Nose
Growth Studies
In 1967, Posen conducted a longitudinal growth study of the nose. He was one of
the first to realize that it was essential for orthodontists to understand the growth of the
nose to better understand esthetic soft tissue profile outcomes. He noted that nasal
growth changes in size and form were significant after the age of 13 years. He found an
increase in length along with angular and linear measurements that determined the nose
grew in a downward and anterior manner.40 Posen agrees with Subtelny, Behrents,
Chaconas et al., Formby et al., Forsberg and Nanda et al. that there is an increase in
length (Table 2.4)13, 21-22, 24,
29-30, 33
and Posen agrees with Subtelny that there is a
downward and forward displacement of the nose with
age;13, 21, 40 this displacement occurs more in a vertical direction rather than horizontal.13,
21, 40
20
Table 2.4. Nasal Changes in Untreated Patients and Patients Treated with Extractions
Length
Direction
Nasal bone relation
Untreated
Increase in
length13, 21-22, 24, 29-30, 33,40-42
Down and forward with more
vertical displacement than
horizontal13, 21, 40
First thought growth of soft
tissue nose is closely related to
nasal bone21 then found that after
adolescence soft tissue nose
grows after bone growth is
complete 33, 41, 42
Treated Extraction
Increase in length26, 32
Not found in literature.
Not found in literature.
In 1990, Genecov, Sinclair and Dechow conducted a study on the development of
the nose and soft tissue profile.41 It was a goal of their study to determine whether or not
there is a relationship between nasal development and Angle classification, but no
relationship was found. Along with agreeing that the nose grows in length with age,
important observations were made regarding the independent growth of the soft tissue
nose compared to hard tissue growth.41 Although it was first thought by Subtelny that the
growth of the soft tissue nose closely followed the growth of the hard tissue nose (Table
2.4),21 Nanda et al. and Genecov et al. evaluated an older sample of patients and found
that after adolescence the soft tissue nose continued to grow after the growth of the hard
tissue nose was complete.33, 41
In 2002, Zankl and his group collected a cross sectional sample with a large age
range to evaluate nose length, nasal protrusion, and philthrum length. They agreed that
not only did the nose increase in length, but they also agreed with Nanda et al. and
Genecov et al. that the soft tissue nose increased past the completion of the hard tissue
nose and continuously increased throughout life (Table 2.4).42
21
Extraction Studies
Anderson et al. and Binda et al. agreed that with extraction treatment, the nose
increased in length (Table 2.4).26, 32
Chin Changes
Growth Studies
Burstone and Subtelny found that with an increase of age alone there was an
increase in mandibular prognathism at the chin;10 Subtelny saw this increase with both
skeletal and soft tissues at a 1:1 ratio.13, 21
Table 2.5. Chin Changes in Untreated Patients and Patients Treated with Extractions
Chin
Mandibular
prograthism
Mandibular
direction
Untreated
Increase with age10
both the skeletal and soft tissue
at a 1:1 ratio13, 21
Mostly downward and some
forward displacement of
pogonion and menton43
Treated Extraction
Increase25-26, 32
Forward displacement of
pogonion and menton43
Extraction Studies
Paquette et al., Binda et al. and Anderson et al. agree that mandibular prognathism
increased with extraction treatment.25-26, 32 In 2009, MacGilpin conducted a study to
evaluate mandibular response to different extraction patterns and techniques. He found
that when there was no treatment the mandible responded with mostly downward and
some forward changes. He also found that with extraction treatment, the chin responded
by displacing forward.43
22
Details regarding the studies mentioned in this section are located in Appendix A.
These details include the type of study, year the study was conducted, and sample
information.
23
Summary and Purpose
A controversy that started over 70 years ago has still not been put to rest: does the
extraction of teeth during orthodontic treatment harm the soft tissue profile of patients in
terms of esthetics?
Many studies have evaluated changes in the soft tissue profile with growth and
treatment separately but a long-term longitudinal study would be helpful to properly
determine the effect of extractions on the soft tissue facial profile from youth to mature
adulthood. In addition, the effects of growth alone needs to be compared at similar time
points in order to better understand what is actually occurring due to the treatment, versus
what would have inevitably occurred with maturation alone.
This study seeks to describe the soft tissue profiles of a sample of patients treated
with extraction and compare these results with a sample of untreated individuals at
similar ages. The purpose of this study is to provide an evidence-based answer to the
age-old questions as to whether or not the extraction of premolars during orthodontic
treatment will improve or harm the esthetics of the resulting soft tissue facial profile over
time.
24
References
1.
Peck H, Peck S. A concept of facial esthetics. Angle Orthod. 1970 Oct;40:284–318.
2.
Asbell M. Norman W. Kingsley (1928-1913). Am J Orthod Dentofacial Orthop.
1999 Jan;115:101.
3.
Asbell MB. A brief history of orthodontics. Am J Orthod Dentofacial Orthop. 1990
Sep;98(3):206–13.
4.
Tweed C. Evolutionary trends in orthodontics, past, present, and future. Am J
Orthod. 1953;39:81–108.
5.
Sarver DM, Ackerman JL. Orthodontics about face: the re-emergence of the esthetic
paradigm. Am J Orthod Dentofacial Orthop. 2000 May;117:575–6.
6.
Broadbent B. A new x-ray technique and its application to orthodontia. Angle
Orthod. 1931;1:45–66.
7.
Steiner C. Cephalometrics in clinical practice. Am J Orthod. 1959;29:8–29.
8.
The Charles H. Tweed International Foundation [Internet]. [cited 2011 Sep
1];Available from: http://www.tweedortho.com/about/tweedyears.asp
9.
Casko JS, Shepherd WB. Dental and skeletal variation within the range of normal.
Angle Orthod. 1984 Jan;54:5–17.
10. Burstone C. Integumental contour and extension patterns. Angle Orthod. 1959;9:93–
104.
11. Ricketts RM. Esthetics, environment, and the law of lip relation. Am J Orthod. 1968
Apr;54:272–89.
12. Burstone C. The integumental profile. Am J Orthod. 1958;44:1–25.
13. Subtelny J. The soft tissue profile, growth, and treatment changes. Angle Orthod.
1961;31:105–22.
14. Steiner C. The use of cephalometrics as an aid to planning and assessing orthodontic
treatment. Am J Orthod. 1960;46:721–35.
15. Kowalski CJ, Walker GF. The Tweed triangle in a large sample of normal
individuals. J. Dent. Res. 1971 Dec;50:1690.
16. Tweed C. Clinical Orthodontics. St. Louis, MO: The C. V. Mosby Company; 1966.
17. Tweed C. The Frankfort-mandibular plane angle in orthodontic diagnosis,
classification, treatment planning, and prognosis. Am J Orthod Oral Surg. 1946
Apr;32:175–230.
25
18. Ricketts R. The keystone triad. II. Growth, treatment, and clinical significance. Am
J Orthod. 1964;50:728–50.
19. Holdaway RA. A soft-tissue cephalometric analysis and its use in orthodontic
treatment planning. Part I. Am J Orthod. 1983 Jul;84:1–28.
20. Buschang PH, Fretty K, Campbell PM. Can commonly used profile planes be used
to evaluate changes in lower lip position? Angle Orthod. 2011 Jul;81:557–63.
21. Subtelny J. A longitudinal study of soft tissue facial structures and their profile
characteristics, defined in relation to underling skeletal structures. Am J Orthod.
1959;45:481–507.
22. Behrents R. Growth of the Aging Craniofacial Skeleton, Craniofacial Growth
Series. 1984.
23. Bishara SE, Hession TJ, Peterson LC. Longitudinal soft-tissue profile changes: a
study of three analyses. Am J Orthod. 1985 Sep;88:209–23.
24. Chaconas SJ, Bartroff JD. Prediction of normal soft tissue facial changes. Angle
Orthod. 1975 Jan;45:12–25.
25. Paquette DE, Beattie JR, Johnston LE Jr. A long-term comparison of nonextraction
and premolar extraction edgewise therapy in “borderline” Class II patients. Am J
Orthod Dentofacial Orthop. 1992 Jul;102:1–14.
26. Anderson JP, Joondeph DR, Turpin DL. A cephalometric study of profile changes
in orthodontically treated cases ten years out of retention. Angle Orthod. 1973
Jul;43:324–36.
27. Bowman SJ, Johnston LE Jr. The esthetic impact of extraction and nonextraction
treatments on Caucasian patients. Angle Orthod. 2000 Feb;70:3–10.
28. Drobocky OB, Smith RJ. Changes in facial profile during orthodontic treatment
with extraction of four first premolars. Am J Orthod Dentofacial Orthop. 1989
Mar;95:220–30.
29. Formby WA, Nanda RS, Currier GF. Longitudinal changes in the adult facial
profile. Am J Orthod Dentofacial Orthop. 1994 May;105:464–76.
30. Forsberg CM. Facial morphology and ageing: a longitudinal cephalometric
investigation of young adults. Eur J Orthod. 1979;1:15–23.
31. Sarnäs KV, Solow B. Early adult changes in the skeletal and soft-tissue profile. Eur
J Orthod. 1980;2:1–12.
26
32. Binda SK, A M Kuijpers-Jagtman, Maertens JK, van’t Hof MA. A long-term
cephalometric evaluation of treated Class II division 2 malocclusions. Eur J Orthod.
1994 Aug;16:301–8.
33. Nanda RS, Meng H, Kapila S, Goorhuis J. Growth changes in the soft tissue facial
profile. Angle Orthod. 1990;60:177–90.
34. Bloom L. Perioral profile changes in orthodontic treatment. Am J Orthod.
1961;47:371–9.
35. Hershey HG. Incisor tooth retraction and subsequent profile change in
postadolescent female patients. Am J Orthod. 1972 Jan;61:45–54.
36. Wholley CJ, Woods MG. The effects of commonly prescribed premolar extraction
sequences on the curvature of the upper and lower lips. Angle Orthod. 2003
Aug;73:386–95.
37. Holdaway RA. A soft-tissue cephalometric analysis and its use in orthodontic
treatment planning. Part II. Am J Orthod. 1984 Apr;85:279–93.
38. Rudee D. Proportional profile changes concurrent with orthodontic therapy. Am J
Orthod. 1964;50:421–34.
39. Waldman BH. Change in lip contour with maxillary incisor retraction. Angle
Orthod. 1982 Apr;52:129–34.
40. Posen JM. A longitudinal study of the growth of the nose. Am J Orthod. 1967
Oct;53:746–56.
41. Genecov JS, Sinclair PM, Dechow PC. Development of the nose and soft tissue
profile. Angle Orthod. 1990;60:191–8.
42. Zankl A, Eberle L, Molinari L, Schinzel A. Growth charts for nose length, nasal
protrusion, and philtrum length from birth to 97 years. Am. J. Med. Genet. 2002 Sep
1;111:388–91.
43. MacGilpin D. Mandibular Displacement in Class II Patients Treated With Different
Extraction Patterns and Techniques [Internet]. 2009;Available from:
http://www.slu.edu/Documents/cade/thesis/Macgilpin_Thesis.pdf
27
CHAPTER 3: JOURNAL ARTICLE
Abstract
Introduction: Controversy exists in literature regarding facial esthetics with
extraction and non-extraction treatment. Purpose: The purpose of this study is to
provide an evidence-based answer to the question: whether or not the extraction of
premolars during orthodontic treatment will improve or harm the esthetics of the resulting
soft tissue facial profile. This longitudinal study investigates changes in the soft tissue
profile after treatment and again 25+ years later. Methods: Cephalometric films were
traced on a sample of 57 untreated individuals and a sample of 47 individuals treated with
extractions. The mean ages of the untreated sample were 16 years 0 months and 56 years
and 8 months respectively and were matched to the mean ages of an extraction treated
sample, 15 years 11 months and 39 years and 4 months respectively. Descriptive
statistics were collected and individual t-tests were performed for the purpose of
comparison and contrast. Results: The results show that without treatment, the soft
tissue profile generally changes in a downward and forward manner. With extraction
treatment, the downward change which would otherwise happen due to growth is less and
the soft tissue change is mainly forward. This study also shows that the soft tissue
profiles 25+ years post treatment for both the untreated and extraction treated samples are
similar and considered esthetically acceptable. Conclusions: 1) There is no substantive
esthetic difference between the untreated and extraction treated samples. 2) There are
important different directional changes for the soft tissue profiles of untreated and
extraction treated individuals. 3) The changes for the untreated sample are greatest for
the lips and chin and change in a downward and forward direction. 4) The changes for
28
the extraction treated sample are generally greatest for the lips and chin and change in a
forward direction. 5) The results from this study are significant to orthodontics as a
dental specialty and can be used as a treatment planning aid in an effort to positively
direct soft tissue changes. 6) Extractions do not harm the esthetics of the resulting soft
tissue facial profile over time.
29
Literature Review
Although orthodontics is a dental specialty that has seen drastic changes from its
birth to the present there is one common aspect that has maintained itself throughout the
century – a strong emphasis on facial esthetics. Facial esthetic ideals were documented
in art as early as
4 and 5 B.C. by the Greeks and have been noted through time in various early
civilizations of the Egyptians, Romans and Italians.1 Although the ideas surrounding the
correction of the irregularities of teeth was first published in Britain by Kingsley in
1880,2 the relationship between esthetics and orthodontics was not yet addressed.
In 1900, Angle formally established orthodontics as a dental specialty in St.
Louis, Missouri.3 Angle was considered the Father of Modern Orthodontics and insisted
that patients who maintained their full complement of teeth would have superior
occlusion. He also believed once superior occlusion was achieved, superior facial
esthetics would inevitably result.4 Tweed, Angle’s student and originally one of his
followers, challenged Angle on esthetic grounds and exposed that normal occlusion does
not always result in ideal facial balance.4 Tweed recognized that balance and facial
harmony could not be achieved when orthodontically treating some patients without
extraction. In some cases the teeth, and therefore covering soft tissue, became too
protrusive and are not esthetically pleasing.5
In effort to solve the extraction versus non-extraction controversy started by
Angle and Tweed, it was agreed that cephalometric “norms” needed to be defined.6-9
Burstone recognized early that the soft tissue profile was of greater importance when
considering esthetics compared to the skeletal components.10 Cephalometric norms that
30
he defined intended to serve as ideal treatment goals to be achieved by orthodontists both
with the occlusion and more importantly the soft tissue profile.
The effect of growth on the soft tissue profile has been addressed by many studies
detailing the changes due to growth alone.10-18 Of the many, a notable one was
performed by Behrents,11 in 1984, that documented long term longitudinal soft tissue
changes.
Coincidently, changes in the soft tissue profile that occur in extraction and nonextraction treatments are present in the literature.19-28 Although these studies show some
level of predictability with extraction treatment, there are no long term longitudinal
studies that compare the effects of extraction treatment with changes that naturally occur.
Although many studies have evaluated changes in the soft tissue profile with
growth and treatment alone, a long term longitudinal study would be helpful to
completely evaluate the effects of extractions on the soft tissue facial profile from youth
to adulthood. In addition, the effects of growth alone need to be compared at similar time
points to better understand what is occurring due to the extraction treatment versus what
would have inevitably occurred with maturation alone.
This study seeks to evaluate the soft tissue profiles of a sample of patients treated
with extractions and compare the results with a sample of untreated individuals at similar
ages. The purpose of this study is to give an evidence-based answer to the age-old
question: whether or not the extraction of premolars will improve or harm the esthetics of
the soft tissue facial profile.
31
Materials and Methods
Untreated Sample
A sample of 57 individuals was randomly selected from the Bolton Study at Case
Western Reserve University in Cleveland, Ohio. A search was run on the Bolton
database focusing on individuals that had cephalometric films taken in the age ranges of
10 – 17 years and again at 30 – 85 years of age. These age groups were selected with the
intention to match the films to a treated sample approximating the ages typical for after
treatment (T2) and 25+ years post treatment (T3). Films were chosen consecutively until
there were no more individuals that met the including criteria. The sole inclusion criteria
(aside from having high quality cephalometric films with discernable soft tissue profiles)
were that none of the individuals underwent orthodontic treatment.
Treated Sample
A sample of 47 orthodontic patients was selected from a collection of patient files
recalled nearly 25 years after their treatment was completed. Films were chosen
consecutively until there were no more patients that met the including criteria. In order to
meet the inclusion criteria, the patients needed to have high-quality cephalometric films
taken after treatment (T2) and again nearly 25 years post treatment (T3). As with the
untreated films, all had to show good soft tissue definition and contain all of the
landmarks necessary for analysis. All of the patients had 4 premolars extracted during
treatment and all of the patients were treated by the same practitioner who had similar
treatment objectives for all patients in the sample.
32
Analysis
Hard and soft tissue anatomical landmarks initially established by Barnette were
traced for each film.29 Appendix B details the descriptions for each landmark. The
landmarks were traced for both the untreated and treated samples at both time points and
then digitized using Dentofacial Planner 7.0 software.
In Dentofacial Planner, two reference planes were constructed in order to create
an x-y coordinate grid: a horizontal line was created level to the landmark nasion at an
angle parallel to the sella-nasion line minus 70 (SN-7) while a vertical line was created
perpendicular to the parallel line to SN-7 passing through the landmark sella. This is
diagrammed in Figure 3.1.
Figure 3.1. Reference Planes (Modified from Barnette)29
33
Descriptive data were obtained and statistical analysis was performed using the
Statistical Package for the Social Science (SPSS) version 18. Descriptive statistics and
variable analysis were only calculated for 14 landmarks. Facial measurements, soft tissue
thicknesses, and soft tissue lengths were also analyzed with an additional 5 landmarks.
The landmarks used for this study are illustrated in Figure 3.2. Appendix B details how
the facial measurements, soft tissue thickness and soft tissue lengths were measured.
Independent t-tests were performed with a set significance level of p < 0.05 to appraise
the change in position of the selected 14 landmarks and to appraise changes in the facial
measurements, soft tissue thickness, and soft tissue length.
Figure 3.2. Landmarks Used in Analysis (Modified from Barnette)29
34
The percentage of enlargement was considered for both samples. It was
previously determined by Mellion30 that specific films from the extraction group sample
nearly 25 years post treatment (T3) had a reduction in magnification. This was due to the
use of a different cephalostat and consequent reduction in the object-film distance. All of
the films from the Bolton Study were produced with the Bolton cephalometric technique:
there is a constant anode-object distance of 5 feet while the object-film distance, also
called the midline-lateral film distance (ML), is kept to a minimum.31 The ML value is
therefore unique for each patient and also unique to each film that is taken. The ML was
recorded for each film traced and then converted to percentage of enlargement from the
Bolton Standard Technique.31 Once all enlargement values were identified, a conversion
factor was found from the effect of distance from subject to film.32 All distances were
adjusted to 0% enlargement (i.e., life size).
Microsoft Word and Excel from Microsoft Office Edition 2007 were utilized for
table and graph construction. Profile images detailing the soft tissue changes for the
descriptive statistics for each sample were created using Adobe Illustrator CS11.
35
Results
Sample
Data regarding each sample is displayed in Tables 3.1 and 3.2. At post treatment
(T2), the untreated sample mean age was 16 years and 0 months and the extraction
treated sample mean age was 15 years and 11 months. The untreated sample mean age
was 53 years and 0 months at 25+ years post treatment (T3) and the extraction treated
sample mean age was 39 years and 4 months.
Table 3.1. Ages of the Untreated Sample at T2 and T3 Matched to Extraction Sample
Untreated Sample
Minimum
Maximum
Average
Median
Standard Deviation
Ages Matched T2
Ages Matched T3
08 years, 7 months
28 years, 0 months
16 years, 0 months
17 years, 0 months
03 years, 3 months
26 years, 4 months
68 years, 9 months
53 years, 0 months
56 years, 8 months
11 years, 2 months
Table 3.2. Ages of Sample Treated with Extractions for T2 and T3
Treated Sample
Minimum
Maximum
Average
Median
Standard Deviation
Ages T2
Ages T3
11 years, 0 months
22 years, 9 months
15 years, 11 months
15 years, 8 months
02 years, 0 months
32 years, 3 months
46 years, 1 months
39 years, 4 months
39 years, 10 months
03 years, 10 months
Untreated and Extraction Treated Results
The present study aimed to determine whether or not there was a long term
difference in the soft tissue facial profiles of patients that do not undergo orthodontic
treatment compared to those that underwent orthodontic treatment with extractions.
Independent t-test compared the untreated and extraction treated samples at post
treatment (T2) and also at 25+ years post treatment (T3) and can be seen in Appendix C.
At post treatment (T2) all of the vertical landmarks for the untreated sample were
36
significantly smaller. Pronasale and the inferior nasal tip were smaller in the horizontal
direction for the untreated sample. At 25+ years post treatment all of the vertical
landmarks for the untreated sample were significantly smaller except pronasale and the
inferior nasal tip. Pronasale, the interior nasal tip, and soft tissue menton were smaller in
the horizontal direction for the untreated sample.
Figures 3.3 and 3.4 represent the landmarks at post treatment (T2) and 25+ years
post treatment (T3) respectively. These figures are not to scale. Note in Figure 3.3. that
the size of the soft tissue profile for the untreated sample at post treatment (T2) was
smaller than the size of the soft tissue outline for the extraction treated sample at post
treatment (T2). The untreated sample shows a smaller nose, smaller lips, and a smaller
chin.
37
Figure 3.3. Post Treatment (T2) for Untreated (solid dots) and Extraction Treated (hollow
dots) Samples
38
Figure 3.4. 25+ Years Post Treatment (T3) for Untreated (solid dots) and Extraction
Treated (hollow dots) Samples
Untreated and Extraction Treated Differences
The differences between the untreated samples from post treatment (T2) to 25+
years post treatment (T3) were compared to the differences between the extraction treated
samples from post treatment (T2) to 25+ years post treatment (T3) and the results of the
independent t-tests for the landmark data are seen in Table 3.3. Differences were
significant for horizontal and vertical pronasale, horizontal and vertical inferior nasal tip,
vertical superior labial sulcus, vertical labrale superius, vertical labrale inferius, vertical
labiomental fold, vertical soft tissue pogonion, vertical soft tissue menton, horizontal and
39
vertical A point, vertical lower incisor tip, vertical B point, vertical pogonion and vertical
menton. For all of the significant landmarks, the changes were larger in the untreated
sample. The direction of change was more horizontal and vertical.
Table 3.3. Comparison of Post Treatment (T2) Differences and 25+ Years Post Treatment
(T3) Differences for Untreated and Extraction Treated Samples
Measurement
x=Horizontal
y=Vertical
Untreated
Mean + SD
(mm)
x Prn
y Prn
x Int
y Int
x Sls
y Sls
x Ls
y Ls
x Li
y Li
x Lmf
y Lmf
x Pog’
y Pog’
x Me’
y Me’
x A point
y A point
x U1
y U1
x L1
y L1
x B point
y B point
x Pog
y Pog
x Me
y Me
* denotes p < 0.05
7.62 + 5.38
1.74 + 5.15
7.31 + 5.50
2.14 + 5.09
5.68 + 5.67
3.61 + 4.92
4.88 + 6.53
5.27 + 5.18
8.45 + 7.17
1.47 + 5.95
9.96 + 7.96
4.69 + 5.90
11.62 + 9.08
6.38 + 6.53
11.62 + 10.16
7.42 + 7.18
7.20 + 5.23
2.53 + 4.62
8.21 + 6.44
1.99 + 4.80
7.79 + 6.30
2.53 + 5.00
8.68 + 7.82
3.16 + 5.76
10.38 + 8.77
5.19 + 6.72
10.48 + 9.25
5.62 + 6.88
Extraction
Treated
Mean + SD
(mm)
4.32 + 5.28
-1.13 + 4.45
4.42 + 5.64
-0.08 + 4.00
3.39 + 7.39
1.19 + 3.86
3.80 + 8.28
1.86 + 3.76
3.38 + 9.32
-1.92 + 4.06
8.57 + 10.03
0.03 + 4.78
11.13 + 11.45
1.83 + 5.44
12.67 + 12.20
1.05 + 4.41
4.50 + 6.54
0.22 + 3.42
6.86 + 9.21
0.49 + 3.21
6.23 + 8.93
-0.69 + 3.54
8.26 + 10.27
-0.12 + 4.34
10.05 + 11.77
0.65 + 4.34
10.49 + 12.24
1.09 + 4.42
40
t
Sig. (2-tailed)
3.16
3.06
2.64
3.36
1.33
2.83
0.75
3.90
1.25
3.45
0.78
4.48
0.24
3.89
-0.45
5.58
2.30
2.95
0.89
1.92
1.02
3.87
0.23
3.32
0.16
4.18
0.00
4.09
.002*
.003*
.010*
.001*
.187
.006*
.468
.000*
.214
.001*
.439
.000*
.813
.000*
.657
.000*
.024*
.004*
.396
.058
.311
.000*
.820
.001*
.872
.000*
1.00
.000*
Independent t-tests were also performed to show the significant differences
between post treatment and 25+ years post treatment (T3) time points for the untreated
and extraction treated sample. Results for facial measurements, soft tissue thickness and
soft tissue length are seen in Tables 3.4-3.6.
For the facial measurements, the hard tissue facial angle, and the nasolabial angle,
the mentolabial fold, and the change for the upper and lower anterior facial height were
significantly different. The hard tissue facial convexity angle changed more for the
extraction treated sample and became less convex, the nasolabial angle and the
mentolabial angle changed more for the untreated sample and became less convex, and
the upper and lower anterior facial heights changed more for the untreated samples and
became larger.
For the soft tissue thickness differences between the post treatment (T2) and 25+
years post treatment (T3), rhinion and B point changed significantly. Rhinion and B
point for the untreated sample changed more and became thicker than for the extraction
treated sample. For soft tissue length, the upper and lower lip and the nose length
changed significantly more for the untreated sample than the extraction treated sample.
41
Table 3.4. Comparison of Post Treatment (T2) and 25+ Years Post Treatment (T3) Facial
Measurement Differences
Facial
Measurements
x=Horizontal
y=Vertical
Na’ – Prn – Pog’
Na – A point – Pog
(Reference to 180o)
Int – Sbn - Ls
Li – Lmf – Pog’
(Reference to 180o)
Na’ – Sbn
Sbn – Me’
* denotes p < 0.05
Untreated
Mean + SD
(mm)
t
Sig. (2-tailed)
1.81 + 5.03
1.60 + 11.37
Extraction
Treated
Mean + SD
(mm)
1.49 + 4.10
-5.39 + 7.52
0.36
-2.03
.720
.046*
-4.44 + 8.54
-22.89 + 26.26
-0.96 + 7.29
-0.15 + 14.68
-2.25
-5.60
.026*
.000*
3.22 + 3.31
3.69 + 4.87
0.73 + 2.32
-1.21 + 3.48
4.52
6.00
.000*
.000*
Table 3.5. Comparison of Post Treatment (T2) and 25+ Years Post Treatment (T3) Soft
Tissue Thickness Differences
Soft Tissue
Thickness
x=Horizontal
y=Vertical
Rhn-Rhn’
A point - Sls
B point - Lmf
Pog-Pog’
* denotes p < 0.05
Untreated
Mean + SD
(mm)
0.37 + 0.86
-0.76 + 3.39
1.43 + 1.59
1.48 + 1.97
Extraction
Treated
Mean + SD
(mm)
-0.04 + 0.95
-0.10 + 2.68
0.31 + 1.16
0.93 + 1.94
t
Sig. (2-tailed)
2.31
-1.10
4.18
1.44
.023*
.274
.000*
.154
Table 3.6. Comparison of Post Treatment (T2) and 25+ Years Post Treatment (T3) Soft
Tissue Length Differences
Soft Tissue
Length
x=Horizontal
y=Vertical
Sbn-Ls
Lmf-Li
Na’-Prn
* denotes p < 0.05
Untreated
Mean + SD
(mm)
3.91 + 3.22
1.44 + 2.11
4.85 + 3.91
Extraction
Treated
Mean + SD
(mm)
2.23 + 1.70
0.24 + 2.17
1.76 + 2.78
42
t
Sig. (2-tailed)
3.44
2.87
4.72
.001*
.005*
.000*
Figure 3.5 is a visual representation of the changes that occurred from post
treatment (T2) to 25+ years post treatment (T3) for the untreated and extraction treated
samples respectively. These figures are not to scale.
Figure 3.5. Changes from T2 to T3 for the Untreated Sample (left) and Extraction Treated
Sample (right)
In an effort to better understand the results, the differences seen in the untreated
and extraction treated samples from post treatment (T2) to 25+ years post treatment (T3)
were broken into large, moderate, and small amounts of change (seen in Table 3.7).
Large change for the horizontal direction was considered 10.00 to 12.00 mm while a
large change for the vertical direction was considered 5.00 to 7.00 mm. A moderate
amount of change in the horizontal component was considered 7.00 to 10.00 mm and a
moderate change for the vertical direction was considered 2.00 to 5.00 mm. A small
amount of change in the horizontal direction was considered 3.00 to 7.00 mm and a small
43
amount of change for the vertical direction was considered 0.00 to 2.00 mm. Large,
moderate, and small were determined from the total range of change in the horizontal and
vertical direction for the untreated and extraction treated sample.
Table 3.7. Changes Categorized into Large, Moderate and Small (in mm)
Large Change (mm)
Moderate Change (mm)
Small Change (mm)
Horizontal Direction
10.00-12.00
7.00-10.00
3.00-7.00
Vertical Direction
5.00-7.00
2.00-5.00
0.00-2.00
The untreated sample showed the most change for hard and soft tissue pogonion
and menton. The change was large in the horizontal direction and also had a large
vertical component. A moderate amount of change was seen for the labiomental fold, B
point, labrale inferius, the lower incisor tip, the upper incisor tip, A point, pronasale, and
the inferior nasal tip in the horizontal direction. A moderate amount of vertical change
was seen in the labiomental fold, B point, the lower incisor tip, the upper incisor tip, A
point, and the inferior nasal tip; all landmarks with a moderate horizontal change also
showed a moderate vertical change except the upper incisor tip, labrale inferius, and
pronasale. The superior labial sulcus and labrale superius showed a small amount of
horizontal change but the superior labial sulcus had a moderate vertical component and
labrale superius had a large vertical component. Labrale inferius, the upper incisor tip,
and pronasale all showed a small change in the vertical direction.
The extraction treated sample showed large horizontal change for hard and soft
tissue pogonion and menton. These landmarks, however, all showed a small vertical
component. A moderate horizontal change was seen in the labiomental fold and B point.
These landmarks showed a small vertical component. A small amount of horizontal
change was seen for labrale inferius, the lower incisor tip, the upper incisor tip, A point,
44
pronasale, inferior nasal tip, superior labial sulcus, and labrale superius. All of these
landmarks had a small amount of change in the vertical direction. Interestingly, the
vertical components for B point, labrale inferius, the lower incisor tip, pronasale, and
inferior nasal tip changed in the upward direction.
In general, the untreated sample demonstrated a more downward change and
forward change while the extraction treated sample showed a forward change and with
very little downward change.
45
Discussion
Comparison with Past Studies
The majority of the results from this study agree with past studies. With regard to
facial measurements, the hard tissue facial angle in reference to 180o for the extraction
sample shows a significant change from post treatment (T2) to 25+ years post treatment
(T3). In agreement with Paquette et al., Anderson et al., and Bowman et al., the hard
tissue facial angle becomes flatter with time.22, 25, 27 The flattening is due to the forward
movement of hard tissue pogonion and A point.
The nasolabial angle significantly changes for the untreated sample and becomes
more acute after 25+ years. This finding agrees with Behrents11 and is due to the small
downward movement of the soft tissue nose and the forward movement of the superior
labial sulcus and labrale superius.
The mentolabial angle significantly changes with time and significantly flattens
for the untreated sample. These results agree with the findings of Behrents and Formby
et al.11, 17 The flattening of the mentolabial angle occurs because the labiomental fold
comes forward more than labrale inferius.
The upper and lower anterior face heights show a significant increase for the
untreated sample between the post treatment (T2) and 25+ year post treatment (T3) time
period. There is an agreement with Behrents, Formby et al., Forsberg, and Sarnas et al.
for an increase in the anterior face height.11, 13-14, 17 The increase in the upper anterior
face height is because of the downward movement of pronasale and the inferior nasal tip.
The downward movement of the upper lip and pogonion are the reason for the increase in
the lower anterior face height. The findings from this study show a similar increase for
46
both the upper and lower anterior face heights, while Behrents, Formby et al., Forsberg,
and Sarnas et al. saw a specific increase for either the upper or lower anterior face
heights.
For soft tissue thickness, the dorsal area of the nose significantly changes over the
25+ year period and becomes thicker for the untreated group. These results agree with
Subtelny.12 This occurs because the distance between hard tissue rhinion and soft tissue
rhinion increases with age.
This study also shows a significant change for the soft tissue over B point. This
finding agrees with Subtelny and Nanda et al.12, 16 The forward movement of the
labiomental fold is larger than the forward movement of B point and this is why the soft
tissue over B point increases.
The upper and lower lips significantly change in length from the post treatment
(T2) time point to the 25+ year post treatment (T3) time point. The upper and lower lips
increase in length for the untreated sample and this agrees with the findings of Sarnas et
al. and Nanda et al.14, 16 The upper lip increase occurs because labrale superius relocates
inferiorly and the lower lip increase occurs because the labiomental fold moves
downward a moderate amount while labrale inferius only moves downward by a small
amount.
This study found a significant increase in the length of the nose for the untreated
sample and is in agreement with previous studies.11-13, 16-18, 33- 35 The nose increases in
length due to the downward movement of pronasale and the inferior nasal tip.
Lastly, the chin, which was measured with hard and soft tissue pogonion and
menton, underwent the most changes from post treatment (T2) to 25+ years post
47
treatment (T3). This study agrees with Burstone and Subtelny that mandibular
prognathism in an untreated sample increases with age.10, 12 This is due to the large
forward movement of both hard and soft tissue pogonion and menton. There is also
agreement with Paquette et al., Anderson et al., and Binda et al., that mandibular
prognathism in an extraction treated sample increases with age.22, 25-26 This is again due
to the large forward movement of both hard and soft tissue pogonion and menton. The
direction of mandibular change is noted to be downward and forward for the untreated
sample and almost exclusively forward for the extraction treated sample and these
findings are similar to MacGilpin’s findings.36
Analysis of Untreated and Extraction Treated Samples
To evaluate the esthetics of the soft tissue profiles for both the untreated and
extraction treated samples, Ricketts’ E-plane is utilized. Figures 3.6 and 3.7 show
Ricketts’ E-plane for post treatment (T2) untreated and extraction treated samples and for
25+ years post treatment (T3) untreated and extraction treated samples respectively.
These figures are not to scale.
48
Figure 3.6. Ricketts’ E-plane at Post Treatment (T2) for the Untreated (solid dots) and
Extraction Treated (hollow dots) Samples
49
Figure 3.7. Ricketts’ E-plane at 25+ Years Post Treatment (T3) for the Untreated (solid
dots) and Extraction Treated (hollow dots) Samples
According to Ricketts, the ideal adult lower lip should be located 4 mm behind
the E-plane +/- 3 mm.8 Therefore, both untreated and extraction treated samples at post
treatment (T2) and 25+ years post treatment (T3) can be considered esthetically
acceptable.
Figure 3.8 shows changes for the lips and chin disregarding nasal changes. This
figure demonstrates that although the lips and chin create different line angles at post
treatment (T2), at 25+ years post treatment the samples create similar line angles located
50
close together. This shows that treatment with extractions does not ruin or “flatten” the
soft tissue facial profile when compared to no treatment at all.
Figure 3.8. Lip and Chin Changes for the Untreated (solid lines) and Extraction Treated
(dotted lines) Samples
Clinical Relevance of Present Study
The knowledge from this study can be used as a tool for orthodontic treatment
planning. This study shows that without treatment, soft tissue generally changes in a
downward and forward manner. This study also shows that with extraction treatment the
51
downward change, which would otherwise happen due to growth, is altered and the soft
tissue change is almost exclusively forward. There is, therefore, a difference in the soft
tissue profiles for untreated and extraction treated individuals. Although there is a
difference in the direction of change, there is not, however, a substantive difference in
esthetics.
These results can be applied to orthodontics mainly if a patient is considered on
the borderline of extraction treatment. This may be most useful for dolicocephalic
individuals and patients with open bite tendency.
52
Conclusions
This study aimed to give an evidence-based answer to the question: whether or
not the extraction of premolars will improve or harm the esthetics of the soft tissue
profile. The conclusions drawn from this study are the following:
1) There is no substantive esthetic difference between the untreated and extraction
treated samples.
2) There are important different directional changes for the soft tissue profiles of
untreated and extraction treated individuals.
3) The changes for the untreated sample are greatest for the lips and chin and change in a
downward and forward direction.
4) The changes for the extraction treated sample are generally greatest for the lips and
chin and change in a forward direction.
5) The results from this study are significant to orthodontics as a dental specialty and
can be used as a treatment planning aid in an effort to positively direct soft tissue
changes.
6) Extractions do not harm the esthetics of the resulting soft tissue facial profile over
time.
53
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Asbell MB. A brief history of orthodontics. Am J Orthod Dentofacial Orthop. 1990
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Tweed C. Evolutionary trends in orthodontics, past, present, and future. Am J
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1];Available from: http://www.tweedortho.com/about/tweedyears.asp
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Steiner C. Cephalometrics in clinical practice. Am J Orthod. 1959;29:8–29.
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Casko JS, Shepherd WB. Dental and skeletal variation within the range of normal.
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Ricketts RM. Esthetics, environment, and the law of lip relation. Am J Orthod. 1968
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Holdaway RA. A soft-tissue cephalometric analysis and its use in orthodontic
treatment planning. Part II. Am J Orthod. 1984 Apr;85:279–93.
10. Burstone C. Integumental contour and extension patterns. Angle Orthod. 1959;9:93–
104.
11. Behrents R. Growth of the Aging Craniofacial Skeleton, Craniofacial Growth
Series. 1984.
12. Subtelny J. A longitudinal study of soft tissue facial structures and their profile
characteristics, defined in relation to underling skeletal structures. Am J Orthod.
1959;45:481–507.
13. Forsberg CM. Facial morphology and ageing: a longitudinal cephalometric
investigation of young adults. Eur J Orthod. 1979;1:15–23.
14. Sarnäs KV, Solow B. Early adult changes in the skeletal and soft-tissue profile. Eur
J Orthod. 1980;2:1–12.
15. Bishara SE, Hession TJ, Peterson LC. Longitudinal soft-tissue profile changes: a
study of three analyses. Am J Orthod. 1985 Sep;88:209–23.
16. Nanda RS, Meng H, Kapila S, Goorhuis J. Growth changes in the soft tissue facial
profile. Angle Orthod. 1990;60:177–90.
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17. Formby WA, Nanda RS, Currier GF. Longitudinal changes in the adult facial
profile. Am J Orthod Dentofacial Orthop. 1994 May;105:464–76.
18. Chaconas SJ, Bartroff JD. Prediction of normal soft tissue facial changes. Angle
Orthod. 1975 Jan;45:12–25.
19. Bloom L. Perioral profile changes in orthodontic treatment. Am J Orthod.
1961;47:371–9.
20. Rudee D. Proportional profile changes concurrent with orthodontic therapy. Am J
Orthod. 1964;50:421–34.
21. Hershey HG. Incisor tooth retraction and subsequent profile change in
postadolescent female patients. Am J Orthod. 1972 Jan;61:45–54.
22. Anderson JP, Joondeph DR, Turpin DL. A cephalometric study of profile changes
in orthodontically treated cases ten years out of retention. Angle Orthod. 1973
Jul;43:324–36.
23. Waldman BH. Change in lip contour with maxillary incisor retraction. Angle
Orthod. 1982 Apr;52:129–34.
24. Drobocky OB, Smith RJ. Changes in facial profile during orthodontic treatment
with extraction of four first premolars. Am J Orthod Dentofacial Orthop. 1989
Mar;95:220–30.
25. Paquette DE, Beattie JR, Johnston LE Jr. A long-term comparison of nonextraction
and premolar extraction edgewise therapy in “borderline” Class II patients. Am J
Orthod Dentofacial Orthop. 1992 Jul;102:1–14.
26. Binda SK, Kuijpers-Jagtman AM, Maertens JK, van’t Hof MA. A long-term
cephalometric evaluation of treated Class II division 2 malocclusions. Eur J Orthod.
1994 Aug;16:301–8.
27. Bowman SJ, Johnston LE Jr. The esthetic impact of extraction and nonextraction
treatments on Caucasian patients. Angle Orthod. 2000 Feb;70:3–10.
28. Wholley CJ, Woods MG. The effects of commonly prescribed premolar extraction
sequences on the curvature of the upper and lower lips. Angle Orthod. 2003
Aug;73:386–95.
29. Barnette K. A Longitudinal Cephalometric Study of the Soft Tissue Profile of Male
and Femal Orthodontically Treated Class I and Class II Subjects [Internet].
2008;Available from:
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30. Mellion N. A Longitudinal, Multivariate Analysis of Orthodontic Relapse [Internet].
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31. Broadbent BHS, Broadbent BHJ, Golden WH. Bolton Standards of Dentofacial
Development Growth. St. Louis, MO: The C. V. Mosby Company; 1975.
32. Thurow R. Atlas of Orthodontic Principles. St. Louis, MO: The C. V. Mosby
Company; 1970.
33. Posen JM. A longitudinal study of the growth of the nose. Am J Orthod. 1967
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34. Genecov JS, Sinclair PM, Dechow PC. Development of the nose and soft tissue
profile. Angle Orthod. 1990;60:191–8.
35. Zankl A, Eberle L, Molinari L, Schinzel A. Growth charts for nose length, nasal
protrusion, and philtrum length from birth to 97 years. Am. J. Med. Genet. 2002 Sep
1;111:388–91.
36. MacGilpin D. Mandibular Displacement in Class II Patients Treated With Different
Extraction Patterns and Techniques [Internet]. 2009;Available from:
http://www.slu.edu/Documents/cade/thesis/Macgilpin_Thesis.pdf
37. Fortier E. Soft Tissue Profile Changes in Females 12-20 Years [Internet]. 2000
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f
38. Jacobson A. Radiographic Cephalometry: From Basics to Videoimaging.
Quintessence Pub Co; 1995.
56
APPENDIX A
Detailed Literature Review
Table A.1. Details for Growth Studies
Author
Behrents11
Year
1984
Bishara et al.15 1985
Burstone10
1959
Chocanas et
al.18
Formby et
al.17
1995
Forsberg13
1979
Genecov et
al.34
1990
Nanda et al.16
1990
Posen33
1967
Sarnas et al.14
1980
Subtelny12
1959
Zankl35
2002
1994
Sample
113 individuals with films taken from
17 to 83 years
35 individuals with cephalometric films
taken on a yearly basis between 5 to 17
years and then less frequently to the age
of 25
37 adolescent Caucasians with mean age
of 14.7 years and 40 young adult
Caucasians with a mean age of 23.8
46 Caucasians with records from 10 to
16 years of age
47 Caucasians with ages ranging from
18 to 42 years
49 young adults with mean age of 24.4
years and recalled sample 10 years later
32 Class I and 32 Class II individuals
with cephalometric films taken 3 times
(7 to 9 years, 11 to 13 years, and 16 to
18 years)
40 Caucasians between the ages of 7 to
18 years with cephalometric films taken
yearly
30 individuals from 3 months of age to
18 years
151 Swedish Caucasians with first film
taken at mean age of 21 years and
second film taken 5 years later with
mean age of 26 years
30 individuals with cephalometric films
from 3 mo of age to 18 years
2,500 individuals from birth to 97 years
of age
57
Notes
Recalled patients in late
adulthood for soft tissue
changes
Compared 3 different
cephalometric analyses for
six soft tissue parameters
Evaluated facial changes
without treatment using own
analysis
Attempted to create a
prediction scheme
Evaluated longitudinal
effect of growth on soft
tissue profile
Evaluated longitudinal
facial morphology and aging
Evaluated longitudinal
relationship of nose and
Angle classification
Evaluated longitudinal
growth changes of soft
tissue profile
Evaluated longitudinal
changes of nose
Evaluated longitudinally
soft tissue changes after
puberty
Evaluated longitudinal
effect of growth on soft
tissue profile
Cross sectional evaluation
of the hard and soft tissues
of nose
Table A.2. Details for Extraction Studies
Author
Anderson et
al.22
Year
1973
Binda26
1994
Bloom19
1961
Bowman et
al.27
2000
Drobocky et
al.24
1989
Hershey21
1972
MacGilpin36
2009
Paquette et
al.25
1992
Sample
27 males and 43 females and reevaluated films 10 year after
treatment was completed
81 patients ranging from an average
younger group of 9 years to an
average adolescent group of 14
years, films taken before treatment,
after treatment and 2 and 5 years
after treatment
60 patients with mean start age of
11 years and 6 months and a mean
end treatment age of 14 years and
10 months
58 lay persons and 42 dentists
examined 70 extraction and 50 nonextraction random cephalometric
profiles
160 cephalometric films of patients
initially treated between the ages of
10 to 30 years. Treatment was
completed within 30 months and
the length of time between pre- and
post treatment films did not include
more than 12 months of nontreatment time
36 Caucasian females all past the
age of 16, mean age of 20.3 years
125 pre- and post treatment
cephalometric radiographs of Class
II adolescent patients and 30
untreated Class II individuals
33 extraction and 30 non-extraction
cases with average post treatment
recall time of 14.5 years
58
Notes
Evaluated orthodontic
effects of both extraction
and growth
Evaluated changes of the
soft tissue profile
Evaluated perioral profile
changes with treatment
and with growth alone
Described extraction and
non-extraction profiles
Evaluated profiles of
patients that underwent
extraction orthodontic
treatment
Evaluated post puberty
changes in soft tissue
profile with incisor tooth
retraction
Evaluated difference in
soft tissue profiles for
four different extraction
treatment techniques
Compared soft tissue
facial profiles
Table A.2. Details for Extraction Studies (Continued)
Author
Rudee20
Year
1964
Waldman23
1982
Sample
85 patients with a young age group
from mean age of 6 years 11
months to an older age group mean
of 22 years and 6 months
41 Class II Div. I patients
Wholley et
al.28
2003
80 premolar extraction cases
59
Notes
Evaluated lip retraction
with orthodontic therapy
Evaluated changes of lip
contour in response to
orthodontic treatment
Evaluated effect of
extraction of teeth on
curves of upper and
lower lip
APPENDIX B
Materials and Methods Details
Table B.1. Landmarks and Definitions from Fortier37 and Jacobson38
Abbreviation Landmark
A
Subspinale
B
Supramentale
Col
Columnella
Gn
Gnathion
Gn’
Soft Tissue
Gnathion
Inferior Nasal
Tip
Lower Incisor
Incisal Edge
Lower Incisor
Apex
Labrale
inferius
Labiomental
Fold
Labrale
Superius
Menton
Int
L1
L1a
Li
Lmf
Ls
Me
Me’
Na
Na’
Soft Tissue
Menton
Nasion
Soft Tissue
Nasion
Definition
The deepest midline point of the curve of the maxilla
between the anterior nasal spine and prosthion.
The most posterior point in the midline of the
symphyseal outline of the mandible in the concavity
between infradentale and pogonion.
Landmark on interior surface of the nose, between the
nostrils.
The most anterior and inferior midline point on the
external contour of the symphysis of the mandible. It is
usually determined by bisecting the angle formed by the
mandibular plane and a line through the facial plane (i.e.,
pogonion and nasion).
The most anterior and inferior point on the contour of
the chin.
The inferior point on the nasal tip, as it becomes
confluent with columella.
The incisal tip of the mandibular central incisor.
The root tip of the mandibular central incisor.
The most anterior point on the vermillion border of the
lower lip.
The deepest point in the concavity between labrale
inferius and soft tissue pogonion.
The most anterior point on the vermillion border of the
upper lip.
The most inferior midline point on the symphyseal
outline of the mandible.
The most inferior point on the contour of the chin.
A midline point determined by the intersection of the
internasal suture with the nasofrontal suture. The most
anterior point of the nasofrontal suture seen from norma
lateralis.
The deepest point in the concavity between the nose and
the forehead.
60
Table B.1. Landmarks and Definitions from Fortier37 and Jacobson38 (Continued)
Abbreviation Landmark
Pog
Pogonion
Pog’
Prn
Rhn
Rhn’
Soft Tissue
Pogonion
Pronasale
Rhinion
Soft Tissue
Rhinion
Sbn
Subnasale
Se
Sella Turcica
Sls
Superior
Labial Sulcus
Superior
Nasal Tip
Stomion
Upper Incisor
Incisal Edge
Upper Incisor
Apex
Snt
Stm
U1
U1a
Definition
The most prominent or anterior point on the symphysis
of the mandible in the median plane. Usually determined
by a tangent through nasion.
The most anterior point on the contour of the chin.
Most anterior point on the nasal tip.
The tip of nasal bone.
Located at the junction of the inferior limit of the
concavity of soft tissue nasion and the dorsum of the
nose.
The point where the lower margin of the nasal septum is
confluent with the integumental upper lip.
The center of the pituitary fossa of the sphenoid bone. It
is usually determined by inspection.
The deepest point in the concavity of the upper lip,
midway between subnasale and labrale superius.
The superior point on the nasal tip.
The mid-point of the mouth-slit where the lips touch.
The incisal tip of the maxillary central incisor.
The root tip of the maxillary central incisor.
Table B.2. Measurement Abbreviation Key
Abbreviation
Na’ – Prn – Pog’
Na – A point – Pog (Reference to 180o)
Int – Sbn – Ls
Li – Lmf – Pog’ (Reference to 180o)
Na’ – Sbn
Sbn – Me’
Rhn-Rhn’
A point – Sls
B point – Lmf
Pog-Pog’
Sbn-Ls
Lmf-Li
Na’-Prn
Measurement
Soft tissue facial profile angle including the
nose
Hard tissue facial profile angle in reference to
180o
Nasolabial angle
Mentolabial angle in reference to 180o
Upper anterior face height
Lower anterior face height
Soft tissue thickness at rhinion
Soft tissue thickness at A point
Soft tissue thickness at B point
Soft tissue thickness at pogonion
Upper lip length
Lower lip length
Nose length
61
APPENDIX C
Independent t-Test Results
The post treatment (T2) samples for untreated and extraction treatment were
compared with independent t-tests and the results for the landmark data are seen in Table
C.1. Differences are significant for horizontal and vertical pronasale, horizontal and
vertical inferior nasal tip, vertical superior labial sulcus, vertical labrale superius, vertical
labrale inferius, vertical labiomental fold, vertical soft tissue pogonion, vertical soft tissue
menton, vertical A point, vertical upper incisor tip, vertical lower incisor tip, vertical B
point, vertical pogonion, and vertical menton. For all of the significant landmarks, the
extraction treated sample is larger horizontally and vertically.
62
Table C.1. Post Treatment (T2) Comparison Data of Untreated and Extraction Treated
Samples
Measurement
x=Horizontal
y=Vertical
x Prn
y Prn
x Int
y Int
x Sls
y Sls
x Ls
y Ls
x Li
y Li
x Lmf
y Lmf
x Pog’
y Pog’
x Me’
y Me’
x A point
y A point
x U1
y U1
x L1
y L1
x B point
y B point
x Pog
y Pog
x Me
y Me
* denotes p < 0.05
Untreated
Mean + SD
(mm)
95.08 + 6.33
-42.19 + 5.04
92.46 + 6.33
-48.12 + 5.02
78.65 + 5.49
-61.71 + 4.90
81.13 + 6.00
-67.53 + 5.19
76.49 + 7.06
-82.63 + 6.03
68.54 + 7.60
-88.67 + 6.37
70.32 + 8.82
-101.69 + 7.42
54.89 + 9.98
-117.29 + 7.88
64.30 + 5.14
-54.82 + 4.41
66.38 + 6.43
-76.43 + 5.39
63.05 + 6.24
-72.38 + 5.47
57.36 + 7.52
-89.65 + 6.24
58.80 + 8.69
-102.06 + 7.32
53.02 + 9.09
-110.00 + 7.50
Extraction
Treated
Mean + SD
(mm)
100.36 + 5.31
-47.76 + 5.05
97.61 + 5.42
-52.64 + 4.69
80.27 + 6.29
-67.28 + 4.70
82.62 + 7.01
-73.57 + 4.87
78.56 + 7.56
-90.06 + 5.73
70.49 + 8.41
-98.53 + 6.21
72.63 + 9.80
-113.14 + 6.33
58.12 + 11.72
-129.17 + 6.31
66.32 + 5.83
-60.92 + 3.58
68.02 + 7.33
-83.59 + 4.27
65.29 + 7.27
-81.13 + 4.32
58.77 + 8.44
-99.76 + 5.41
60.59 + 10.28
-114.24 + 6.63
54.40 + 10.44
-121.73 + 6.37
t
Sig. (2-tailed)
-4.65
-4.61
-4.49
-4.75
-1.39
-5.92
-1.16
-6.14
-1.44
-6.45
-1.25
-8.42
-1.26
-8.54
-1.50
-8.58
-1.87
-7.81
-1.20
-7.58
-1.67
-9.17
-0.89
-8.88
-0.95
-8.94
-0.71
-8.68
.000*
.000*
.000*
.000*
.168
.000*
.249
.000*
.154
.000*
.220
.000*
.212
.000*
.138
.000*
.065
.000*
.235
.000*
.098
.000*
.377
.000*
.342
.000*
.480
.000*
Independent t-tests were also performed for the untreated and treated with
extraction post treatment (T2) samples on facial measurements, soft tissue thickness and
soft tissue length and the results are seen in Tables C.2-C.4.
63
For the facial measurements, the soft tissue facial convexity angle, the nasolabial
angle, the mentolabial angle, the upper anterior facial height and the lower anterior facial
height are significantly different. The soft tissue facial convexity angle is more convex
for the untreated sample, the nasolabial angle and mentolabial angle is more acute for the
untreated sample, and the upper and lower anterior facial heights are smaller for the
untreated sample.
There are no significant results for the soft tissue thickness comparison between
untreated and extraction treated samples post treatment (T2). For soft tissue length, the
lower lip and the nose length are significantly longer in the extraction treated sample.
Table C.2. Comparison of Post Treatment (T2) Facial Measurements
Facial
Measurements
x=Horizontal
y=Vertical
Na’ – Prn – Pog’
Na – A point –
Pog (Reference to
180o)
Int – Sbn - Ls
Li – Lmf – Pog’
(Reference to
180o)
Na’ – Sbn
Sbn – Me’
* denotes p < 0.05
Untreated
Mean + SD
(mm)
t
Sig. (2-tailed)
115.23 + 5.48
6.89 + 14.02
Extraction
Treated
Mean + SD
(mm)
124.67 + 4.37
-0.16 + 5.66
-9.83
3.49
.000*
.001
105.66 + 10.21
23.58 + 18.13
115.30 + 9.38
11.68 + 12.63
-5.03
3.72
.000*
.000*
35.37 + 3.92
67.7 + 5.22
38.62 + 3.14
73.78 + 6.14
-4.71
-5.35
.000*
.000*
64
Table C.3. Comparison of Post Treatment (T2) Soft Tissue Thickness
Soft Tissue
Thickness
x=Horizontal
y=Vertical
Rhn-Rhn’
A point - Sls
B point - Lmf
Pog-Pog’
* denotes p < 0.05
Untreated
Mean + SD
(mm)
3.02 + 0.68
16.19 + 2.44
11.44 + 1.43
11.95 + 2.00
Extraction
Treated
Mean + SD
(mm)
2.99 + 0.80
15.52 + 2.69
12.00 + 1.58
12.53 + 1.88
t
Sig. (2-tailed)
0.23
1.31
-1.87
-1.50
.819
.195
.065
.138
Table C.4. Comparison of Post Treatment (T2) Soft Tissue Length
Soft Tissue
Length
x=Horizontal
y=Vertical
Sbn-Ls
Lmf-Li
Na’-Prn
* denotes p < 0.05
Untreated
Mean + SD
(mm)
13.04 + 2.68
10.19 + 1.99
29.16 + 3.82
Extraction
Treated
Mean + SD
(mm)
13.84 + 2.37
11.94 + 2.44
31.12 + 3.27
t
Sig. (2-tailed)
-1.61
-3.95
-2.84
.110
.000*
.005*
Comparison was also done for the untreated and extraction treated samples at 25+
years post treatment (T3) with independent t-tests and the results for the landmark data is
seen in Table C.5. Differences are significant for horizontal pronasale, horizontal inferior
nasal tip, vertical superior labial sulcus, vertical labrale superius, vertical labrale inferius,
vertical labiomental fold, vertical soft tissue pogonion, horizontal and vertical soft tissue
menton, vertical A point, vertical upper incisor tip, vertical lower incisor tip, vertical B
point, vertical pogonion, and vertical menton. For all of the significant landmarks, the
extraction treated sample is larger horizontally and vertically.
65
Table C.5. 25+ Years Post Treatment (T3) Comparison Data of Untreated and Extraction
Treated Samples
Measurement
Untreated
Extraction
x=Horizontal
Mean + SD
Treated
t
Sig. (2-tailed)
y=Vertical
(mm)
Mean + SD
(mm)
x Prn
102.70 + 5.24
104.68 + 4.64
-2.06
.042*
y Prn
-44.92 + 6.15
-46.63 + 4.76
-1.60
.113
x Int
99.77 + 5.14
102.03 + 4.69
-2.36
.020*
y Int
-50.26 + 5.96
-51.79 + 4.61
-1.49
.140
x Sls
84.33 + 5.06
84.20 + 4.95
0.13
.900
y Sls
-65.33 + 6.08
-68.47 + 4.84
-2.95
.004*
x Ls
86.00 + 5.43
86.42 + 5.35
-0.40
.693
y Ls
-72.78 + 6.32
-75.43 + 4.90
-2.41
.018*
x Li
84.94 + 6.03
84.94 + 5.70
0.00
.999
y Li
-84.09 + 6.11
-88.15 + 5.35
-3.62
.000*
x Lmf
78.50 + 6.50
79.06 + 5.99
-0.45
.651
y Lmf
-93.37 + 7.41
-98.56 + 6.21
-3.91
.000*
x Pog’
81.93 + 7.31
83.76 + 6.83
-1.32
.191
y Pog’
-108.07 + 7.61
-115.00 + 6.07
-5.17
.000*
x Me’
66.52 + 8.18
70.80 + 8.21
-2.66
.009*
y Me’
-124.71 + 7.78
-130.22 + 6.47
-4.00
.000*
x A point
71.50 + 4.62
70.83 + 4.85
0.72
.474
y A point
-57.36 + 4.40
-61.14 + 3.44
-4.94
.000*
x U1
74.60 + 5.67
74.87 + 6.08
-0.24
.814
y U1
-78.42 + 5.07
-84.07 + 4.36
-6.13
.000*
x L1
70.84 + 5.61
71.51 + 5.72
-0.60
.548
y L1
-74.91 + 5.40
-80.45 + 4.45
-5.76
.000*
x B point
66.05 + 6.09
67.04 + 6.27
-0.81
.419
y B point
-92.81 + 6.34
-99.63 + 5.87
-5.71
.000*
x Pog
69.18 + 7.00
70.64 + 7.07
-1.06
.291
y Pog
-107.24 + 7.50
-114.90 + 6.62
-5.55
.000*
x Me
63.51 + 7.44
64.88 + 7.30
-0.95
.344
y Me
-115.61 + 7.37
-122.82 + 6.54
-5.31
.000*
* denotes p < 0.05
Independent t-tests were also performed for the untreated and treated with
extraction 25+ years post treatment (T3) samples on facial measurements, soft tissue
thickness and soft tissue length and the results are seen in Tables C.6-C.8.
For the facial measurements, the soft tissue facial convexity angle, the hard tissue
facial angle, and the nasolabial angle are significantly different. The soft tissue facial
66
convexity angle is more convex for the untreated sample, the hard tissue facial convexity
is less convex for the untreated sample, and the nasolabial angle is more acute for the
untreated sample.
For soft tissue thickness comparison between untreated and extraction treated
samples at 25+ years post treatment (T3), rhinion is significantly thicker for the untreated
sample. For soft tissue length, the nose length is significantly longer in the untreated
sample.
Table C.6. Comparison of 25+ Year Post Treatment (T3) Facial Measurements
Facial
Measurements
x=Horizontal
y=Vertical
Na’ – Prn – Pog’
Na – A point –
Pog (Reference to
180o)
Int – Sbn - Ls
Li – Lmf – Pog’
(Reference to
180o)
Na’ – Sbn
Sbn – Me’
* denotes p < 0.05
Untreated
Mean + SD
(mm)
t
Sig. (2-tailed)
117.03 + 5.33
8.49 + 18.83
Extraction
Treated
Mean + SD
(mm)
126.16 + 5.55
-1.09 + 6.50
-8.52
3.98
.000*
.000*
101.21 + 11.28
0.69 + 28.63
114.34 + 8.61
2.20 + 14.12
-6.76
-0.35
.000*
.725
39.34 + 2.58
72.57 + 5.27
-1.38
-1.05
.171
.295
38.59 + 3.06
71.44 + 5.79
67
Table C.7. Comparison of 25+ Year Post Treatment (T3) Soft Tissue Thickness
Soft Tissue
Thickness
x=Horizontal
y=Vertical
Rhn-Rhn’
A point - Sls
B point - Lmf
Pog-Pog’
* denotes p < 0.05
Untreated
Mean + SD
(mm)
3.40 + 0.96
15.43 + 3.48
12.88 + 1.65
13.43 + 2.43
Extraction
Treated
Mean + SD
(mm)
2.94 + 0.72
15.42 + 2.94
12.31 + 1.46
13.44 + 2.01
t
Sig. (2-tailed)
2.73
0.02
1.88
-0.04
.007*
.987
.062
.972
Table C.8. Comparison of 25+ Year Post Treatment (T3) Soft Tissue Length
Soft Tissue
Length
x=Horizontal
y=Vertical
Sbn-Ls
Lmf-Li
Na’-Prn
* denotes p < 0.05
Untreated
Mean + SD
(mm)
16.96 + 2.92
11.64 + 2.87
34.00 + 3.43
Extraction
Treated
Mean + SD
(mm)
16.06 + 2.73
12.18 + 2.24
32.88 + 2.93
68
t
Sig. (2-tailed)
1.61
-1.08
-1.81
.110
.282
.073*
VITA AUCTORIS
Anita Bhavnani was born June 5, 1985 in Bradenton, Florida to Pritam and Neela
Bhavnani. She was raised in Bradenton, Florida with her older brother, Rajan. The
family moved from Bradenton, Florida to Brookfield, Wisconsin and then finally settled
in Scottsdale, AZ. After graduating from Desert Mountain High School with an
International Baccalaureate Diploma in 2003, she attended Case Western Reserve
University in Cleveland, Ohio. In 2005, she continued her higher education at Case
School of Dental Medicine where she received her D.M.D. (Doctor of Dental Medicine)
in 2009. She was accepted into the orthodontic program at Saint Louis University where
she will graduate in January of 2012.
69