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The relationship of the forehead to the maxillary central incisor in adult white females: an evaluation of Andrews Element II analysis

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The relationship of the forehead to the maxillary central incisor in adult white females: an evaluation of Andrews Element II analysis

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THE RELATIONSHIP OF THE FOREHEAD TO THE MAXILLARY CENTRAL INCISOR IN
ADULT WHITE FEMALES: AN EVALUATION OF ANDREWS ELEMENT II ANALYSIS

by

Samuel Lee

____________________________________________________________________

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

May 2011

Copyright 2011 Samuel Lee
ii

Dedication
To my beautiful wife Cindy Lee,
To my precious son Caleb Lee,
And to my loving parents, Kang and Sung Lee

iii

Acknowledgements
A special thank you to:
Dr. Glenn Sameshima
Dr. Will Andrews
Dr. Reyes Enciso
Dr. Tim Tremont
Dr. Jeff Zapalac
Dr. David Quast

iv

Table of Contents
Dedication ii
Acknowledgements iii
List of Tables v
List of Figures vi
Abstract vii
Chapter 1: Introduction 1
Chapter 2: Review of Literature 4
Chapter 3: Hypotheses & Research Questions 30
Chapter 4: Subjects and Methods 32
Chapter 5: Results 37
Chapter 6: Discussion 53
Chapter 7: Assumptions 58
Chapter 8: Limitations 59
Chapter 9: Summary 60
Chapter 10: Conclusions 62
Bibliography 63

v

List of Tables
Table I: Andrews Element II Analysis Definitions 15
Table II: Head Position Definitions 19
Table III: AP Measurements (mm) Descriptive Statistics 38
Table IV: Kruskal-Wallis Test 41
Table V: (a) Control vs Office 1 AP Measurements, (b) Significance 42
Table VI: (a) Control vs Office 2 AP Measurements, (b) Significance 43
Table VII: (a) Control vs Office 3 AP Measurements, (b) Significance 43
Table VIII: (a) Office 1 vs Office 2 AP Measurements, (b) Significance 44
Table IX: (a) Office 2 vs Office 3 AP Measurements, (b) Significance 44
Table X: (a) Office 1 vs Office 3 AP Measurements, (b) Significance 45
Table XI: Forehead Inclination Descriptive Statistics 46
Table XII: ANOVA Comparison between 4 groups 46
Table XIII: Post-Hoc Tests – Dunnett 47
Table XIV: Intraclass Correlation Coefficient for AP Measurements 52
Table XV: Intraclass Correlation Coefficient for Forehead Inclination 52

vi

List of Figures
Figure 1: Profile Discrepancy 2
Figure 2: Soft Tissue Analyses 6
Figure 3: Harmony Values 12
Figure 4: Forehead Shapes 16
Figure 5: Forehead Inclination determines AP Position of Jaws 17
Figure 6: Landmarks and Reference Lines 18
Figure 7: Example of image used in control sample 32
Figure 8: Example of image used in study sample 33
Figure 9: Forehead with Landmarks 35
Figure 10: Reference Lines used in study 35
Figure 11: Example of PowerPoint slide with only measurement lines 36
Figure 12: (a-d) Control, Office1, 2 and 3 Histograms 39, 40
Figure 13: Boxplot Comparisons of Controls, Office 1, 2 and 3 41
Figure 14: (a-d) Correlations: AP Position of Incisor and Forehead Inclination 48, 49
Figure 15: (a-d) Incisor Position relative to Superion, FFA point and Glabella 50, 51

vii

Abstract
Background: Facial esthetics is an important motivating factor for many patients seeking
orthodontic treatment. Traditionally in orthodontics, facial profiles have been evaluated
using cephalometrics and repose soft-tissue analysis. In this study we want to evaluate
the significance of the profile soft-tissue analysis when the patient is smiling.
Purpose: Our purpose is to evaluate and compare the anteroposterior relationship of the
maxillary central incisors to the forehead in adult white females with harmonious profiles
versus adult white female orthodontic patients.
Methods: 94 photographic images of adult white females with good facial harmony
(control sample) were compared with 150 photographs of adult white females seeking
orthodontic treatment from 3 separate offices (study sample). All images smiling profile
images had the maxillary central incisors and the forehead in full view. The images were
adjusted and rotated to the upright head position. Reference lines were drawn to measure
the anteroposterior positions of the maxillary central incisors as well as forehead
inclinations.
Results: Our results indicate that there is a significant difference in anteroposterior
position of maxillary central incisor between the control sample (harmonious profiles)
and each office [control and office 1 (p=.002), control and office 2 (p=.000), and control
and office 3 (p=.004)]. ANOVA and Nonparametric analysis indicate that our results are
significant. Also there was a significant correlation in the control sample (R
2
= 0.641)
between anteroposterior incisor position and forehead inclination, however none in the
study samples. The most esthetic maxillary central incisor position, between FFA point
viii

and glabella, was highest in the control sample (94%), but much less in the three offices
(Office 1 = 22%, Office 2 = 30%, Office 3 = 30%).
Conclusion: The forehead can be confirmed as a reliable landmark for assessing the facial
profile for adult white females as it relates to anteroposterior maxillary central incisor
position relative to FFA. Treatment goals should include a harmonious relationship
between the anteroposterior position of maxillary central incisors and the forehead for
adult white female patients.

1

Chapter 1: Introduction
Historically, orthodontic treatment planning has placed an emphasis on hard
tissue landmarks and obtaining an end goal of a Class I occlusion. However, a final
result of a Class I occlusion does not necessarily produce an esthetic soft tissue profile. If
the treatment result is a stable and functional occlusion, but the esthetics of the soft tissue
profile has been worsened by orthodontics, then the treatment should not be considered a
success, and will be a source of discontent for the patient.
Facial esthetics is one of the most important motivating factors for a patient
seeking orthodontic treatment [1,2]. Evaluating the face in the profile is a significant
element of a complete orthodontic diagnosis. Over the last two decades, there has been a
growing emphasis placed on assessing the soft tissue profile just as meticulously as the
hard tissue analysis, when treatment planning. Different methods for evaluating facial
profiles have been proposed including traditional cephalometrics as well as repose soft
tissue analysis [3]. In traditional cephalometrics, internal bony landmarks are used to
define various points, lines and planes, which ultimately are used to quantify
anteroposterior (AP) jaw and incisor positions. However there can be error when
identifying landmarks based on the identifier as well as the variability in their positions
between individuals [4,5]. Also more importantly, good facial harmony has been shown
to exist within a broad range of cephalometric values [6].
Due to the limitations of traditional cephalometrics, others began to include soft
tissue landmarks such as the nose, lips and chin to improve cephalometric profile analysis
[7,8,9]. The problem with identifying soft tissue structures alone, however, is that it does
2

not reliably convey the position of the underlying hard tissue structure [10]. An example
of this is shown when looking at the nasolabial angle of similar profile individuals, and
then comparing their maxillary incisor position (Figure 1).
Figure 1. Profile Discrepancy

Andrews, W. 2008
The inclination of the upper lip (nasolabial angle) does not reliably reflect the underlying
anteroposterior position of the maxillary central incisors when they are directly viewed. (A) A patient with
an acute nasolabial angle with the maxillary central incisors positioned well behind glabella. (B) A patient
with an acute nasolabial angle with the maxillary central incisors positioned forward of glabella.

Also, just changing the AP hard tissue will not predictably result in a favorable
response of the nasolabial angle or upper lip curvature [11,12,13]. Changing just the AP
position of the maxilla or maxillary incisors in order to correct soft tissue alone could
result in undesirable positions of the maxillary incisors relative to other external facial
structures when the incisors are viewed directly in profile.
3

The appearance and position of the maxillary incisors should be considered a part
of the face from both the frontal and lateral profiles. Current orthodontic diagnosis
includes the frontal smiling photograph, displaying the maxillary incisors. The lateral
smiling profile, with maxillary incisors displayed, is not typically assessed in terms of
how it relates to the face. The typical lateral profile photograph is taken with the lips in
rest position, and is therefore unreliable in assessing the relationship of the maxillary
incisors to the rest of the face. Previous studies have not specifically looked at this
relationship, until 2008, when a study was done by Will Andrews to assess AP
relationship of the maxillary central incisors relative to the forehead in adult white
females [3].
This study will expand upon Andrews‘ findings to include patients from other
orthodontic offices in different areas of the United States. The objective of the study is to
provide a more in depth evaluation and comparison of the anteroposterior relationship of
the maxillary central incisors to the forehead in adult white females with harmonious
profiles and adult white female orthodontic patients.

4

Chapter 2: Review of Literature
Facial Esthetics and Motivation
Facial beauty and harmony were very important treatment goals of Dr. Edward
Angle. He believed that the face of the Greek god Apollo contained all the necessary
aspects of harmony and beauty [16]. Facial esthetics is one of the most important social
and psychological motivators for people seeking dental treatment. Personality profiles
and the motivations for seeking orthodontic treatment were investigated in a sample of
adult patients. An improvement in dental esthetics was found to be the prime motivating
factor, and the decision to seek treatment was usually made by the adult patients
themselves [1, 2]. There are shared concerns of smile and profile appearance in
orthodontics, orthognathic surgery and prosthodontics [14, 15].
Riedel [17] looked specifically at esthetics and its relationship to orthodontic
therapy. He recognized orthodontics is not only important for improving function, but
improving esthetics and maintaining it. This motivating factor is not only in adults but
children as well. In a study gathered from 473 parents of children being screened at an
orthodontic graduate clinic, 85% of children seeking treatment mentioned concerns over
their appearance of their teeth. Also another 44% has reported being teased about their
appearance [18].

5

Traditional cephalometrics and reliability
Traditional orthodontic treatment planning places more emphasis on internal
osseous landmarks for cephalometrics [3]. Traditional cephalometrics such as: Down‘s,
Ricketts, Steiner, Tweed as the McNamara to name a few, are examples of
cephalometrics that place a heavy emphasis on ideal positioning of hard tissue landmarks
[19]. Osseous landmarks are not reliable as most traditional norms are based off of
Caucasian European Males [6, 20]. Several studies have assessed the reliability of
specific head film measurements, such as landmark identification, conventional angles
and linear measures and found that not all measurements are always able to be
reproduced the same [4,5, 20-24].
The soft tissue is measured mainly from a subjective point of view, and in much
less detail than hard tissue. In four separate traditional analyses, soft tissue is measured
mostly by assessing lip position [25].

6

Figure 2. Soft tissue analyses

James, 1998.

A) Ricketts analysis: a reference line, the ‗‗E‘‘ line, was drawn from the tip of the nose to the soft
tissue pogonion. The distances from the upper lip and lower lip to the E line were measured in
millimeters.
B) Steiner analysis: the upper reference point is at the center of the S-shaped curve between the
subnasale and the nasal tip. The inferior landmark is soft tissue pogonion. The distances from the
upper lip and lower lip to the reference line were measured.
C) Holdaway analysis: an angle, termed the ‗‗H angle,‘‘ between the soft tissue facial plane (Nasion-
Pogonion) and a line tangent to the upper lip and soft tissue pogonion (‗‗H‘‘ line), and the distance
from the lower lip to H line were measured.
D) Merrifield analysis: the inner angle between the profile line (tangent to the soft tissue chin and the
more prominent point of the upper lip or lower lip) and the FH plane was measured, called the
‗‗Z‘‘ angle.

When numerical values are used to measure soft tissue profiles, the lateral
cephalometric norms may be specific to an ethnic group and cannot always be applied to
other ethnic types. With soft tissue as in osseous tissue measurements, in spite of
possible ethnic differences, most classical cephalometric standards are based on sample
populations of people with European-American ancestries [26]. In a comparative study
of Japanese and European-American adults, [27] reported greater ethnic differences in
soft tissue relationships than in skeletal and dentitional relationships. Hwang et al,
7

compared Korean profiles to European-American profile, in both males and females, in
order to understand the ethnic differences in soft tissue profiles between the two groups.
The samples showed differences in nasal inclination, lip protrusion as well as chin
protrusion [26].
Battagel specifically looked at the imprecision involved in cephalometric tracing.
Three different techniques were examined: the error attributable to a single recording, its
associated confidence limits, and the coefficient of reliability. Data from two different
error studies were pooled and used to compare the accuracy of 12 skeletal, dental and soft
tissue measurements, using various assessments from each of the three techniques. He
found that precision needed for cephalometric measurements cannot be improved by just
repeated recording, magnifying the object or just using a more accurate recording device.
Therefore since the cephalometric radiograph is not a precise tool, significant errors are
involved in its measurement [28].

How to “measure” facial esthetics
Society looks at more than just lip positions and values overall facial esthetics.
Therefore if facial esthetics is such an important factor for patients seeking orthodontic
treatment, then it is necessary to include soft tissue assessment along with hard tissue
assessment to get an overall understanding of facial harmony [29]. Nanda described that
balancing the position of the lips in relation to the nose and chin has a direct relationship
with esthetic preference. Growth studies have clearly shown that dynamic changes in
dental, skeletal, and facial integument occur over the entire period of active growth and
8

even into the decades past the age of 20 years [30]. Esthetic standards need to be
different for children and for adults. Treatment results should be projected to when the
patient is well into adulthood. Facial types also have different patterns of growth and
maturational patterns vary [30-34]. The compensatory nature of soft-tissue growth in the
different facial types needs to be considered. In measuring facial attractiveness, caution
must be used when comparing to mean data from growth studies and applying them to all
individuals at all ages, because of the wide variation among individuals in all races and
both sexes [35-37].
Studies have also been done to compare ratings between laypersons, general
dentists, orthodontic residents as well as orthodontics to understand if facial
attractiveness is assessed similarly in amongst all groups [38-40]. In general there is a
consistency when rating facial attractiveness. Tulloch, et al had three views (2 full face
and 1 profile) of 18 orthodontic patients, viewed by a panel of three separate groups (16
orthodontic residents, 17 dental students and 71 undergraduate students). Ratings for
facial attractiveness were based on a visual analog scale. It was found that there was no
specific view favored over the other [41].
Spyropoulos, et al. studied facial profiles under the assumption that the form of
the soft tissue outline largely determines the esthetics of the whole face. Pretreatment
color lateral profile photographs of 20 female patients were used. The photographs were
scanned, and the soft tissue outlines were digitized. The average outline of the 20
original photographs was used to create a template in order to warp the images. Three
additional photographs were constructed with 1 face—the composite average of the 20
9

original photographs—and 3 hairstyles from 3 of the original pictures. These
photographs were judged by orthodontists and lay people. It was found that even when
profiles were the same, some faces were judged differently on an attractiveness scale
based on other factors used to warp the images. This showed the other factors may
contribute to facial esthetics than merely soft tissue profile alone [42].

Cephalometrics to measure facial attractiveness: diagnosis and treatment planning
Proffit writes about the evolving diagnostic approach to orthodontics. Up until
recently, orthodontic diagnosis and treatment planning has been based mostly on hard
tissue relationships and on the Angle idea that considers dental occlusion ideal when it is
natural. In this view, the orthodontist and nature work together in seeking the ideal.
Proffit writes ―In the modern biological model, variation is accepted as the natural form;
ideal occlusion is the exception rather than the rule, and the orthodontist and nature are
often adversaries. The orthodontist's task is to achieve the occlusal and facial outcomes
that would most benefit that individual patient, whose esthetic concerns are often
paramount.‖ Because the soft tissues play a large role in determining the limitations of
orthodontic treatment, which is function and stability, as well as esthetics, the
orthodontist must treatment plan according to the patient's limits of soft tissue adaptation
and soft tissue contours. This emerging focus on soft tissue in diagnosis and treatment
planning places greater emphasis on clinical examination of soft tissue function and
esthetics than has been done previously. Proffit emphasizes the important of more
studies needed on soft tissue cephalometrics [43]. Earlier studies looked at incorporating
10

soft tissue and esthetics into treatment planning [44-49]. However recently, there have
been more studies developed beginning to incorporate in more detail, soft tissue and
facial keys involved in esthetics [9, 26, 50, 51].
Spradley looked at five soft tissue points inferior to the nose in 25 males and 25
females with esthetically pleasing profiles. A true vertical line was constructed through
subnasale and perpendicular to a horizontal line based on natural head position. His
study showed minimal variation in these soft tissue points and therefore concluded that
this sagittal soft tissue assessment could be useful in orthodontic treatment planning [52].
McNamara also developed a way to assess soft tissue because he felt that there
was inconsistency in the construction of lines for the analysis of soft tissue contours. His
evaluation of soft tissue involved identifying soft tissue points and developing tangential
angles to measure soft tissue angles that he felt was relevant to studying soft tissue.
Some of the contours he thought were necessary to measure were: forehead angle,
nasolabial angle, nasal tip angle, and upper lip-nasion perpendicular [26].
Holdaway looked specifically at cephalometric soft tissue analysis as he saw
limitations in using hard tissue analysis alone for treatment planning. He stated that in
his Tweed cases there was about 20-25% that lacked facial harmony even when they had
the ideal Tweed values. He was one of the first to notice that better treatment could be
set if orthodontists quantitated the soft tissue features which contributed or detracted from
the physical attractiveness stereotype. Holdaway looked at ways to measure soft tissue
and came up with norms he felt were necessary for ideal finished cases such as: 1) An H
Angle within 1-2 degrees of average for the convexity measurement of the individual, 2)
11

a curl of the upper lip measuring 4-6mm, 3) the lower lip on the H Line or within 1mm of
it (reference). He was also one of the first to look at Visual Treatment Objective (VTO).
He described that once the soft tissue profile objective was understood in terms of how
the lips respond to when the teeth are moved, dental repositioning could be planned to
bring about the desired change. Holdaway goes on to describe the specific steps involved
in the VTO process [53].
Soft tissue cephalometric analysis has also become an integral tool in
orthognathic surgery [7, 8, 50]. Arnett and Bergman studied 19 facial keys necessary in
orthodontic diagnosis and treatment planning recognizing that tooth movement, whether
it be orthodontic or surgical, used to correct the bite could negatively impact facial
esthetics if pretreatment esthetics were not considered prior to treatment. They
recognized the difference between dental keys and facial keys. Dental keys such as:
overjet, canine occlusion and molar occlusion are given a lot of consideration for
treatment however facial keys are often not looked at with as much detail. Typically
facial keys used by orthodontists include relative positions of the upper lip, lower lip and
chin, which give information yet limited insight for comprehensive diagnosis. Arnett and
Bergman came up with a Soft Tissue Cephalometric Analysis (SCTA), in order to
properly determine the facial keys that need to be in harmony.

12

Figure 3. Harmony Values

Arnett et al, 1999
A) Intramandibular harmony: relationships between structures within the mandible that determine
balance are measured, lower incisor to Pog‘, lower lip to Pog‘, soft tissue B‘ to Pog‘, and neck
throat point to Pog‘ are depicted.
B) Interjaw relationships: relationships between the upper and lower jaw soft tissues that determine
balance are measured, Subnasale to Pog‘, soft tissue A‘ to soft tissue B‘, upper lip anterior to
lower lip anterior.
C) Orbital rim to jaws: relationships between the soft tissue orbital rim and upper and lower jaw that
determine balance are measured, soft tissue orbital rim to upper jaw at soft tissue A‘ point and
lower jaw at Pog‘.
D) Total face harmony: relationships between the forehead, upper jaw, and lower jaw that determine
balance are measured, facial angle (G‘-Sn-Pog‘), forehead at glabella to upper jaw at soft tissue
A‘, and forehead at glabella to lower jaw at Pog‘.
The SCTA integrates occlusal correction and soft tissue balance, with a total of 45
measurements, with only 5 of those related to hard tissue measurements. However Arnett
and Bergman mention that the SCTA itself is also not a stand-alone cephalometric
analysis and is meant to be used in combination with a clinical full examination and
cephalometric treatment planning in order to provide clinically relevant information to
aid in diagnosis and treatment planning [50].
13

Andrews Element II Analysis: Definitions
Lawrence F. Andrews, the founder of the straight-wire appliance, developed the
―Six Elements to Orofacial Harmony‖ [54]. In Element II of the Andrews Analysis, the
eminence and inclination of the forehead is used to correctly assess the anterior-posterior
(AP) position of the jaws and teeth that will create the most esthetic profile. The position
of the maxillary incisors somewhat influences the soft tissue profile and can be
manipulated by the orthodontist to a certain extent.
Andrews believes that the Element II Analysis works better than other analyses for
multiple reasons, including [54]:
 Internal landmarks are not clinical.
 Society uses external landmarks to critique profile esthetics and
orthodontists should too.
 Dentoskeletal landmarks do not always correlate with pleasing facial esthetics.
 The existence of many other cephalometric analyses shows there is no reliable
correlation between the position of internal landmarks and the correct AP position
of the jaws because various analyses are depended on.
 The identification of osseous landmarks is variable.
 Many cephalometric analyses rely on nose and chin landmarks to help identify the
correct AP position of the jaws. However, the nose and chin are often areas that
patients are esthetically unhappy with and want changed.
Andrews‘ rationale for using the forehead and the head‘s frontal plane includes:
14

 The forehead is a part of the face, while internal landmarks are not.
 Without orthodontics, the AP relationship of the maxillary incisor to the forehead
remains constant and will not change.
 In terms of facial harmony, the orientation of teeth to the forehead‘s prominence
and inclination is more predictable than internal cephalometric landmarks.
 This AP relationship is not influenced by race, age, culture and gender.
Andrews claims that his visual method of visually looking at the correct anterior-
posterior position of the maxillary incisor is reliable and more consistent than internal
landmark determination. He also says that the measurement range rarely exceeds 3 mm
in the AP direction when examined by multiple orthodontists.
Even with the accuracy of the clinical measurement method that Andrews reports,
he admits that the Goal Anterior-Limit Line (GALL), is the ―most subjective part of the
Six Elements.‖ [54]

15

Table I. Andrews’ Element II Analysis Definitions

Andrews’ Element II Analysis Definitions [54]
Trichion

Where the flat portion of the forehead from glabella
meets the hairline
Superion

Where the flat portion of the forehead from glabella
to trichion, becomes rounded or angular

Forehead’s Facial Axis Point
(FFA Point)

The midpoint of the clinical forehead (glabella to
superion/trichion) on the forehead‘s midsagittal plane

Facial Axis Point
(FA Point)

A point on the midsagittal plane of the face of the
clinical crown midway between the gingiva and
incisal edge

Forehead’s Anterior-Limit
Line
(FALL)

A vertical line parallel to the head‘s frontal plane that
passes through the FFA point

Dentition’s Anterior-Limit
Line
(DALL)

A line parallel to the head‘s frontal plane that passes
through the maxillary incisor‘s FA point

Goal Anterior-Limit Line
(GALL)

A line parallel to the head‘s frontal plane that passes
through the forehead somewhere between the FFA
point and glabella

16

Figure 4. Forehead Shapes

A) Straight Forehead B) Rounded Forehead C) Angular Forehead
Andrews, L. 2001

Andrews categorizes a subject‘s forehead as being either straight, rounded, or
angular (Figure 4). The straight forehead profile, as shown by three variations in Figure
4A, can appear canted in a posterior direction. However, the forehead is constructed by
one straight plane. The rounded and angular forehead types (Figure 4B and 4C
respectively), contrastingly, are made up of two definitively different planes which
intersect at the point superion. In subjects with rounded and angular foreheads, only the
clinical forehead from superion to glabella is used. This plane from superion to glabella
17

can appear more vertical than a straight forehead. However, the labels of straight,
rounded and angular are always assessed from trichion to glabella in the profile view.
The AP position of the jaws is considered to be Element II, or ―ideal,‖ when the
Facial Axis (FA) point of the maxillary incisor touches the GALL. The AP position of
the GALL is dependent on the angulation of the forehead and also unique for each
individual. A subject with a flat forehead will have a GALL located more posteriorly
(Figure 5A), while a very angular forehead will produce a more anteriorly positioned
GALL (Figure 5C).

Figure 5. Forehead Inclination Determines AP Position of Jaws

A B C
Andrews, L. 2001
The Forehead‘s Anterior-Limit Line (FALL) is defined as a line parallel to the
head‘s frontal plane that passes through the midpoint of the clinical forehead, the
18

Forehead‘s Facial Axis point (FFA point). The Dentition‘s Anterior-Limit Line (DALL)
is defined as a line parallel with the head‘s frontal plane that passes through the Facial
Axis point (FA point) of the maxillary central incisor (Figure 6). When the clinical
forehead is angulated 7 degrees or less from the head‘s frontal plane, then the Goal
Anterior-Limit Line (GALL) passes through the FFA point. When this occurs, the FALL
and GALL are coincident. For every degree that the forehead is angulated greater than 7
degrees, the GALL passes through a point of the forehead 0.6mm anterior to the FFA
point, but never anterior to glabella [54].

Figure 6. Landmarks and Reference Lines

Andrews, L. 2001
GMALL
19

Natural Head Position
The orientation of a patient on clinical exam is an important factor to Andrews‘
Analysis. The orientation of the head of the patient will influence the location of the
FALL/DALL/GALL in relation to the FA point of the central incisor. Therefore the
method used must be able to be produce a reliable and consistent head position otherwise
a poor position will build error into Andrews‘ measurements. Andrews makes use of
extracranial reference planes such as the true vertical line (TVL) and true horizontal line
(THL). He does not use intracranial references because they can vary over periods of
growth and between individuals. Also, natural head position (NHP) and natural head
orientation (NHO) are both useful positions for photographic and soft tissue profile
studies because profiles can be positioned without internal landmarks or cephalometrics.

Table II. Head Position Definitions

Head Position Definitions

Natural Head
Position (NHP)

A standardized and reproducible orientation of the head
when the subject is focusing on a distant point at eye level
and the visual axis is therefore horizontal [55-60]

Natural Head
Orientation (NHO)

The head orientation of the subject perceived by the
experienced clinician, as the natural head position when the
subject is focusing on a distant point at eye level [55, 56]
Natural Head
Posture

An ―orthoposition,‖ captured when taking the first step from
a still to a walking posture. This position is reproducible for
an individual, but can differ greatly among subjects,
especially those with free versus obstructed nasal breathing
[58, 61]

20

Natural head position (NHP) is a standardized and reproducible orientation of the
head when the subject is focusing on a distant point at eye level and the visual axis is
therefore horizontal [55-60]. By orienting the subject in NHP, extracranial reference
lines such as the TVL and THL may be used for reference. Various studies have been
able to calculate repeated NHP registrations to vary by 1.5°-2° which is a very minor
amount compared to the variability in intracranial reference lines [55, 56].
The idea of natural head position is confusing in orthodontics. Natural head
posture, for example, as defined by Moorrees [58], is an ―orthoposition,‖ captured when
taking the first step from a still to a walking posture. This position is reproducible for an
individual, but there can be variations, especially those with free versus obstructed nasal
breathing.
Moorrees

[58, 59] recommends that patients be seated upright and look straight
ahead to a point exactly at eye level on the wall in front of them or into a mirror at eye
level. Moorrees says that due to asymmetry in right and left ear openings, using earposts
can cause inaccurate tilting of the subject [59]. By not using earposts, Moorrees says the
patient has the freedom to adopt a more natural and less manipulated head position.
According to Moorrees, the analysis of facial morphology of a patient in NHP will be
more reliable than interpretations of relationships based off of intracranial reference lines,
because like Andrews, he notes that intracranial reference points are subject to biological
variation and therefore their relationships to each other will also vary.
Cooke and Wei [61] looked at the clinical reproducibility of natural head posture
and the effects of ear posts, a wall mirror, gender and time. Their study was on 217
21

Chinese children, whereby natural head posture was determined to be highly reproducible
on a cephalometric radiograph. All subjects were recorded in the ―orthoposition,‖ except
for those subjects without earposts who were captured in the self-balance posture. Self
balance posture was produced by by forward and backward oscillations of the head,
allowing the head to settle. The results proved that natural head posture is highly
reproducible. The most reproducible scenario was that of immediate recordings (4-10
minutes apart), with a mirror, but no earposts. The only gender difference occurred when
changing from the self-balance position to having a mirror eye reference. Boys looked
up more (mean change 2 degrees); while there was no change in girls posture. Natural
head posture with earposts and mirror became slightly less reproducible over time.
Method error after 4-10 minutes and 1-2 hours was 1.9°. After 3-6 months, this method
error increased to 2.3°. Cooke and Wei also found that by allowing a subject to reorient
themselves upon introduction of a wall mirror and ear posts, the natural head posture
would reflect a position more similar to natural head position, not posture.
While studies have shown natural head position (NHP) to be a valid and reliable
position, other studies have also demonstrated that some subjects upon when asked to
relax will orientate themselves in a very ―unnatural‖ head position. Positioning oneself
into NHP can involve proprioception from the internal ear, eyes, muscle bones and
tendons. It is argued that physiological, psychological and pathological factors can play a
part and influence NHP [56].
Lawrence F. Andrews acquired the FALL/DALL measurement while the subject
was in an adjusted natural head position, similar to the method reported by Lundström
22

and Lundström [55, 56]. Lundström and Lundström

defined natural head orientation
(NHO) to be the head orientation of the individual adjusted by the clinician from the
subject‘s NHP. This position is ―natural‖ as observed by the clinician. Therefore NHO
is very similar to NHP except when the subject presents with ―unnatural‖ flexion or
extension of the head. Only then, will adjustments be made by the clinician to these
unnatural positions to NHO. All other patients who present with a natural appearing
NHP will not have positions adjusted and therefore their NHO will equal their NHP. A
clinician can correct the head position of those tense subjects with head tipped slightly up
or down and by doing so, decrease the range of error. NHO was introduced to further the
contribution of NHP to cephalometrics.
Lundström et al

[55] looked at the accuracy and reliability of NHO using NHP
profile photographs cut into circular shapes. 27 orthodontic patients (14 boys and 13
girls) were instructed to stand relaxed in front of a vertical mirror, 1 meter ahead of them
and look into their reflection. Four assessors were shown two of the photographs
accepted as good examples of NHP. The round profile photographs of each of the
remaining 25 subjects were then positioned by each of the 4 assessors on a white
rectangular paper placed over a larger black rectangular paper. Each assessor positioned
each profile into NHO. A ruler was lined up on soft tissue nasion (N‘) and soft tissue
pogonion (Pg‘) and the extension of this line marked on the white rectangular paper.
This procedure was repeated again three weeks later. Angles between the elongated N‘-
Pg‘ line and the right side of the paper were measured and representative of the estimated
profile orientation in NHO on two separate occasions. Results showed a high correlation
23

(r=0.82-0.96) between assessors for deviations from NHP in estimating NHO. The
correlation of two photographic registrations (r=0.9), shows that there is a difference
between NHP and NHO that results from habitual deviations of NHP from NHO. NHO
is therefore the preferred reference line. Mean differences in NHO for the three-week
period varied between 0.1° and 2.9°. Based on the results from Lundström et al [55], a
distinction is made where NHP is a registered, mirror orientated head position in a
relaxed body and head posture, while NHO is the head position estimated by a trained
clinician as natural. NHO corrects gross errors in registrations and habitual tendencies in
subjects who posture into an ―unnatural‖ position.
Lundström and Lundström [57] compared NHO and NHP with Frankfort
horizontal and the sella-nasion line, where it was determined that due to the inconsistency
of intracranial reference lines, the reference lines are not fitting cephalometric references.
Instead, the extracranial horizontal reference plane in relation to NHO, with minor
variations, was recommended. In Arnett et al

[50], the Soft Tissue Cephalometric
Analysis is recorded in Lundström and Lundström‘s [57] NHO to correct for outlying
unnatural head positions.

Soft tissue adaptation to hard tissue changes
Diagnosis and treatment planning in orthodontics has begun to see the limitations
in traditional cephalometrics alone, and with recent literature, has started to include a
more in-depth evaluation of soft tissue [9, 50, 54, 62]. Several studies have looked at the
difficulty in predicting soft tissue adaptability to hard tissue changes [12, 13, 63-65].
24

Hambleton looked at the soft tissue and noted that although a goal in orthodontics
was for a harmonious soft tissue profile, that was sometimes difficult to achieve due to
the variability of the bone thickness and variations in thickness of and tension of soft
tissues [66]. Other studies looked specifically at the lips and found that lip change was
also not always predictable [63, 67].
Kuyl assessed the integumental profile and the underlying skeleton. In his study,
four test groups comprising 10 orthodontists, 10 senior dentists, 10 junior assistants and
10 dentists assessed horizontal and vertical skeletal pattern from a series of slides of 100
patients. Cephalometric analysis was also carried out using various conventional
analyses. From the study, it was concluded that the soft tissue profile does not
adequately reflect the underlying skeleton [10].
Kasai did an in depth study of both the static and dynamic state of soft tissue, and
its response to hard tissue changes. The samples consisted of lateral cephalograms from
297 Japanese women for the static analysis and 32 sets of lateral cephalograms of pre and
posttreatment adult orthodontic patients for the dynamic analysis. In the static state, the
vertical dimension of lower facial height and the position of the lower incisors were
associated with the thickness of the upper-lip vermilion and soft tissue B point, and the
horizontal upper relationships between upper and lower jaw positions were associated
with the thickness of upper lips and of pogonion (soft tissue chin). In the dynamic state,
the results showed that changes of stomion and lower lip could be predicted and strongly
represented the changes of hard tissue. The overall results in the study provided evidence
towards a strong but complex relationship between hard and soft tissue changes. Also
25

certain linear combinations of selected hard tissue variables could be used to predict soft
tissue changes, however orthodontists need to apply certain prediction methods with
discretion due to the variable nature of soft tissues [68].
Several studies specifically looked at the effect of profile and esthetic changes
with extractions and found that there was no clear predictable relationship between
extraction of premolars and esthetic profiles [25, 69-71]. Maxillary retraction was also
looked at specifically as this movement could affect lip response, therefore altering facial
profile [11-13]. Lo found that the nasolabial angle did not change with growth, however
with increased incisor retraction, there was a significant increase in nasolabial angle [11].
However due to the variability of the anatomy of the upper lip, there is a low degree of
predictability associated with upper lip response from orthodontic movements [72-75].
Since lip movement is still affected by maxillary central incisor position, it is necessary
to determine ideal maxillary central incisor positioning and how it relates to the profile as
a whole in regards to facial esthetics.

Soft tissue analyses regarding the position of maxillary central incisors
Andrews recommends using the forehead prominence and inclination to
determine the correct sagittal position of the maxillary central incisors, but there have
been other methods recommended before.
Arnett‘s Analysis [7, 8, 50] created a comprehensive method and normative
values for soft tissue cephalometrics. His reasoning for such an analysis is that both soft
tissue thickness and dentoskeletal factors contribute to the esthetic profile. His norms
26

were created by selecting 46 adult Caucasians (20 male and 26 females) with natural
class I occlusions. Cephalograms were taken with patients in natural head orientation
(Lundström et al [55]) and TVL was drawn through subnasale. Arnett concluded that
dentoskeletal means did not statistically differ for males and females, however, males‘
soft tissue thicknesses were statistically greater than females. Female subjects showed
more upper lip protrusion (larger upper lip angle, statistically significant at P<0.05) and
greater AP incisor projection (statistically significant at P<0.05). There was no
statistically significant difference in glabella projection relative to the subnasale TVL.
Because of gender differences do exist in certain areas, Arnett recommends separate set
of norms for males and females.
Bass‘ Analysis [31, 32] analyzes the soft tissue profile and evaluates the correct
position of the upper incisors within the face for the optimal smile. Bass argues that
orthodontic treatment cannot change the upper third of the face but only influence the
lower third. Therefore, it is reasonable to look specifically at the lower facial third using
subnasale as a reference. Bass uses a corrected natural head position. On the lateral
cephalogram, the landmarks identified are subnasale and A-point.. V-point is defined as
the midpoint of subnasale and A-point. The distance between A-point and V-point is
then bisected (to account for one quarter of the thickness of the upper lip) and a vertical
line is dropped. Bass‘ Analysis states that the middle third of the labial surface of the
maxillary central incisor should lay tangent to this line. Bass states that the proper AP
position of the maxillary incisors provides for good display during smile and proper
inclination. Assuming an average crown-root angle, Bass‘ Analysis also provides for
27

proper root angulation. In relation to esthetics, soft tissue harmony will be achieved
when incisors are in the correct AP position [31, 32].
Agostino et al [76] evaluated whether the protrusion of the nose and chin would
influence the how orthodontists would perceive the ideal tooth anterior limit line. One
male and one female subject were photographed in natural head position. For each
subject, two photographs were taken, one repose and one on-smile. 17 computer-
morphed images (Dolphin Imaging 8.2) were then created of each of the two subjects.
Images included lengthening and shortening of the nose and chin in increments of 2, 4, 6
mm and 4 images with combinations of the most maximum modifications. A panel was
made up of 19 orthodontic residents and 12 orthodontists. Each judge was given the
images and forms with a visual analogue scale (VAS). On each graph, was a sign
corresponding to the real AP position of the upper incisor in the photograph. Judges were
directed to mark with a vertical line the position of the upper incisor thought to be the
best from an esthetic point of view. The distances between actual and preferred incisor
position were measured to the nearest half-millimeter and statistical analysis concluded
that the esthetic evaluation of the sagittal position of the upper central incisors is
independent of the protrusion of the nose and chin.
Schlosser et al

[77] studied differences in preferences for the anterior-posterior
(AP) position of the maxillary incisor between orthodontists and lay panels. According
to Andrews, society unconsciously compares the AP relationship of the maxillary incisor
to the forehead to assess profile acceptance. Therefore, if this relationship is altered,
profile rejection by panelists should occur. A profile on-smile photograph was taken of
28

one female with Element II incisors and Class I occlusion. The image was then
manipulated by a computer, with 1 mm increment denture movements of the maxillary
central incisor in a horizontal plane to + 4 mm protrusion and retrusion. A panel of
orthodontists (20) and non-orthodontists (20) rated the attractiveness of the photographs
according to a 100 mm VAS (―0‖ least attractive, ―100‖ most attractive). Results
indicated that the 4 mm retrusive photograph was significantly less desirable than all
others. Normal or protrusive preference was evident and orthodontic training did not
significantly alter the magnitude of ratings of preference. Schlosser concluded that the
Andrews Element II Analysis is a useful tool to evaluate facial attractiveness relative to
the maxillary incisor position.
Will Andrews [3] studied the AP relationship of the maxillary central incisors to
the forehead specifically in adult Caucasian females seeking orthodontic treatment (study
sample) with adult Caucasian females with harmonious profiles (control). All
photographs had maxillary central incisors and forehead fully bare and were scanned,
resized and rotated to an ―upright‖ head position. Landmark points, trichion, superion,
glabella, FA point and FFA point were identified on each image. Vertical lines through
the FFA point, FA point and glabella were drawn. A forehead inclination line was drawn
to measure and record the forehead angle. Measurements were taken to look at the
relationship between the forehead and maxillary central incisor. Results indicated that
there was a strong correlation for the control group between the position of the incisor
and forehead inclination (r
2
=0.642) compared to the study sample (r
2
= 0.094). 93% of
the control sample subjects had maxillary central incisors between FFA and glabella,
29

while only 21% of those subjects in the study sample had maxillary incisors positioned in
this range. In conclusion, W. Andrews reported that the forehead is a useful landmark for
examining the profile of adult Caucasian females in relation to the AP position of the
maxillary central incisor and that treatment goals should include the condition that the
maxillary central incisor of an adult Caucasian female should be positioned between the
FFA point and glabella.

30

Chapter 3: Hypotheses & Research Questions
The objective of this study was to expand upon Andrews W. findings using the
Element II analysis (reference article) by including patients from three separate offices
and comparing them to the control sample. The questions we want to answer are:
 Is the forehead a reliable landmark in determining esthetic positioning of the
maxillary central incisor?
 Is Andrews Element II analysis a useful and more efficient soft tissue
cephalometric tool that should be incorporated into orthodontic diagnosis and
treatment planning?
 Should the lateral smiling photo be included as a standard diagnostic photo for
pre-treatment and post-treatment records?
We hypothesize that:
 Anteroposterior position (mm) and Forehead inclination (degrees)
measurements are significantly different between each office and the control
sample.
 Anteroposterior position (mm) and Forehead inclination (degrees)
measurements are significantly different between each of the three offices.
 There is a strong correlation between Forehead Inclination and the
Anteroposterior position of the maxillary central incisor in harmonious
profiles.
31

Null- hypotheses
 There is no significant difference in Anteroposterior position (mm) and
Forehead inclination (degrees) measurements between each office and the
control sample.
 There is no significant difference in Anteroposterior position (mm) and
Forehead inclination (degrees) measurements between each of the three
offices.
 There is a weak or no correlation between Forehead inclination and
Anteroposterior position of the maxillary central incisor in harmonious
profiles.

32

Chapter 4: Subjects and Methods
The control sample consisted of 94 facial profile photographic images of adult
white females collected from various publications, primarily fashion magazines and
newspaper advertisements.
The inclusion criteria were that the maxillary central incisors and forehead were
fully bare (Figure 7). The individuals, having been selected to appear in such
publications, possessed inherently good facial harmony. The exclusion criteria were any
images of poor quality, limiting the ability to identify required landmarks (maxillary
central incisors and forehead).
Figure 7. Example of image used in control sample

Andrews, W. 2008
33

The study sample consisted of pretreatment facial-profile photographic images
from 150 adult white females, age 18-50 years old, seeking orthodontic treatment from
three orthodontic offices. Office 1 was located in Pittsburgh, Office 2 was located in
Texas and Office 3 was located in Kentucky (Figure 8). The selection of the 50 patients
(with a complete set of beginning records) from each office was done alphabetically.
Only active patient files were used. No specific skeletal, dental, or facial characteristics
were used to select the sample.
Figure 8. Example of image used in study sample

Andrews W. 2008
All study sample images from each office were sent on a compact disc as JPEG
files. The images were then imported into Adobe Photoshop CS4, adjusted to the same
34

pixel dimension and resolution, resized to an approximate life-size and rotated to an
estimated upright head position. Once adjusted, resized and uprighted, the images were
then imported into Microsoft PowerPoint. The final upright head position was
confirmed by two independent observers. Approximate life size was determined the
using the average vertical distance from trichion (hairline) to the incisal edge of the
maxillary central incisors measured on the pretreatment lateral cephalograms of a
randomly selected sample of 10 adult white female patients. The 10 subjects all had the
trichion marked with barium paste prior to taking the head film. This distance was 142
mm.
Landmark points for the forehead were identified as described by Andrews
[54] (trichion, superion, glabella, and the FFA point) and marked on each image using the
drawing tool in PowerPoint (Figure 9). Trichion is defined as the hairline and is the most
superior aspect of the forehead when the forehead is of relatively flat contour. Glabella is
defined as the most inferior aspect of the forehead. Superion is defined as the most
superior aspect of the forehead when the forehead is either rounded or angular in contour.
The FFA point is defined as the midpoint between trichion and glabella for foreheads
with flat contour or the midpoint between superion and glabella for foreheads with
rounded or angular contour. All of these points lie on the midsagittal plane of the head.
Three vertical reference lines were constructed: line 1 through the FFA point, line 2
through glabella, and line 3 through the maxillary central incisors FA point. A fourth
reference line (line 4) for assessing forehead inclination was constructed by connecting
glabella to the uppermost point of the clinical forehead (superion point or trichion) as
35

described by Andrews (ref) (Figure 10). Forehead inclination was defined as the angle
between line 1 and line 4.
Figure 9. Forehead with Landmarks

Andrews, W. 2008

Figure 10. Reference lines used in the study.

Andrews, W. 2008

Line 1 is through the forehead's FFA point. Line 2 is through glabella. Line 3 is through the maxillary
central incisor's FA point. Line 4 is through superion (or trichion for straight foreheads) and glabella.
36

The photographic image was deleted from each PowerPoint slide, leaving only the
constructed reference points and lines. The slides were then printed on 8½″ × 11″
standard white paper (Figure 11). All measurements were made on the printed paper by
one examiner. The AP relationship of the maxillary central incisors to the forehead was
measured as the distance between line 1 and line 3 using a metric ruler to the closest 0.5
mm. A positive value was assigned when the maxillary central incisors (line 3) were
anterior to the forehead's FFA point (line 1) and negative when posterior. Forehead
inclination was measured as the angle between line 4 and line 1 using a protractor to the
closest 0.5°.
Figure 11. Example PowerPoint slide with only measurement lines.
Line 1
Line 2
Line 3
Line 4
Measurements
1. AP position of
incisors to FFA (Line
3 to Line 1)
2. Forehead Inclination

Measurement 1 is AP position of incisors to FFA in mm (Line 3 to 1) and Measurement 2 is Foreheard
Inclination in degrees (angle between Line 4 and 1).
37

Chapter 5: Results
Statistical Analysis
Descriptive statistics for Antero-Posterior Incisor position relative to FFA are
summarized in Table III. Continuous data were tested for normality with the formal
Shapiro-Wilkison test. ―Variable AP‖ in Controls and Office 2 did not pass the normality
test. Inclination variable in all groups passed the normality test. A Kruskal-Wallis test
was used to compare median AP between the four offices. Kruskal Wallis test is the non-
parametric alternative to ANOVA test and is used for variables which are not normally
distributed. Mann-Whitney tests were used to compare non-parametric variables and
independent t-tests to compare normal variables. Descriptive statistics for Forehead
Inclination are summarized in Table XI. ANOVA test was used to compare ―Inclination‖
between offices. Post-hoc Dunnett paired comparisons were conducted between offices.
SPSS software was used for statistical analyses.

38

Antero-Posterior maxillary incisor position relative to FFA
Table III: Antero-Posterior Measurements (mm) Descriptive Statistics
Group Mean SD Median 95%
Confidence
Interval
Normality
Test
(Shapiro-
Wilkison)
Control 2.5585 1.86342 2.0000 2.1768
2.9402
0.000
Office 1 0.7800 4.50188 1.0000 -.4994
2.0594
0.854
Office 2 0.4800 3.68666 -1.0000 -.5677
1.5277
0.003
Office 3 0.5500 4.99719 0.0000 -.8702
1.9702
0.435

39

Figure 12a: Control

Figure 12b: Office 1

0.00 2.00 4.00 6.00 8.00
AP
0
5
10
15
20
25
30
Frequency
Mean = 2.5585
Std. Dev. = 1.86342
N = 94
for factor= 1.00
Histogram
-10.00 -5.00 0.00 5.00 10.00
AP
0
2
4
6
8
Frequency
Mean = 0.78
Std. Dev. = 4.50188
N = 50
for factor= 2.00
Histogram
40

Figure 12c: Office 2

Figure 12d: Office 3

-6.00 -3.00 0.00 3.00 6.00 9.00
AP
0
5
10
15
20
Frequency
Mean = 0.48
Std. Dev. = 3.68666
N = 50
for factor= 3.00
Histogram
-10.00 -5.00 0.00 5.00 10.00
AP
0
2
4
6
8
Frequency
Mean = 0.55
Std. Dev. = 4.99719
N = 50
for factor= 4.00
Histogram
41

Figure 13: Boxplot comparison of Controls and Offices 1,2 and 3

There was a statistically significant difference in median AP between the 4 offices
(p<.001) using the Kruskal Wallis Test (Table IV) comparing 4 groups of patients (non-
parametric test).

Kruskal-Wallis Test
Table IV: Kruskal-Wallis Test
AP
Chi-Square 23.205
Df 3
Asymp. Sig. .000

1.00 2.00 3.00 4.00
factor
-10.00
-5.00
0.00
5.00
10.00
15.00
AP
107
160
194
42

Paired Comparisons
Paired comparisons are shown in Tables Va-IXb and Table X(a,b). There were
statistically significant differences in median AP between controls and office 1 (p=.002),
controls and office 2 (p=.000), and controls and office 3 (p=.004), according to Mann-
Whitney Test. There were no significant differences in median AP between office 1 and
2 (p=.633), office 2 and 3 (p=.912), and mean AP between office 1 and 3 (p=.809).

Nonparametric Tests - Mann-Whitney Test
Table Va: Control vs Office 1
AP N Mean Rank Sum of Ranks
Control 94 80.40 7558.00
Office 1 50 57.64 2882.00
Total 144

Table Vb: Control vs Office 1 Significance
AP
Mann-Whitney U 1607.000
Wilcoxon W 2882.000
Z -3.129
Asymp. Sig. (2-tailed) .002

43

Table VIa: Control vs Office 2
AP N Mean Rank Sum of Ranks
Control 94 84.39 7933.00
Office 2 50 50.14 2507.00
Total 144

Table VIb: Control vs Office 2 Significance
AP
Mann-Whitney U 1232.000
Wilcoxon W 2507.000
Z -4.707
Asymp. Sig. (2-tailed) .000

Table VIIa: Control vs Office 3
AP N Mean Rank Sum of Ranks
Control 94 79.68 7490.00
Office 3 50 59.00 2950.00
Total 144

Table VIIb: Control vs Office 3 Significance
AP
Mann-Whitney U 1675.000
Wilcoxon W 2950.000
Z -2.842
Asymp. Sig. (2-tailed) .004

44

Table VIIIa: Office 1 vs Office 2
AP N Mean Rank Sum of Ranks
Office 1 50 51.88 2594.00
Office 2 50 49.12 2456.00
Total 100

Table VIIIb: Office 1 vs Office 2 Significance
AP
Mann-Whitney U 1181.000
Wilcoxon W 2456.000
Z -.477
Asymp. Sig. (2-tailed) .633

Table IXa: Office 2 vs Office 3
AP N Mean Rank Sum of Ranks
Office 2 50 50.18 2509.00
Office 3 50 50.82 2541.00
Total 100

Table IXb: Office 2 vs Office 3 Significance
AP
Mann-Whitney U 1234.000
Wilcoxon W 2509.000
Z -.111
Asymp. Sig. (2-tailed) .912

45

T-Test to compare Office 1 vs Office 3
Table Xa: Office 1 vs Office 3

AP

N Mean
Std.
Deviation
Std.
Error
Mean
Office 1 50 .7800 4.50188 .63666
Office 3 50 .5500 4.99719 .70671

Table Xb: Office 1 vs Office 3 Significance
AP t
Sig: 2-
tailed test
Mean Std. Error
95% Confidence
Interval
Lower Upper
Equal
Variances
assumed
.242 .809 .23000 .95120 -1.65762 2.11762

46

Forehead Inclination
Table XI: Forehead Inclination (degrees) Descriptive Statistics
Group Mean SD Median 95%
Confidence
Interval
Normality
Test
(Shapiro-
Wilkison)
Control 13.7500 4.71770 13.0000 12.7837
14.7163
0.251
Office 1 15.6200 4.84090 15.7500 14.2442
16.9958
0.947
Office 2 16.9700 4.83969 17.7500 15.5946
18.3454
0.338
Office 3 15.7600 4.41153 15.5000 14.5063
17.0137
0.648

There was a statistically significant difference in mean Inclination between the 4 offices
(p=.001) using the ANOVA Test comparing 4 groups of patients (Table XII)

Table XII: ANOVA comparison between 4 groups

Sum of
Squares
df Mean Square F Sig.
Between Groups 378.774 3 126.258 5.696 .001
Within Groups 5319.480 240 22.164
Total 5698.254 243

47

Post-Hoc tests
There were statistically significant differences in mean Inclination between controls and
office 2 (p=.001). There were no significant differences in mean Inclination between any
other two paired comparisons. (Table XIII).

Table XIII: Post-Hoc Tests - Dunnett

Comparisons

Mean
Difference
Std. Error Sig.
95% Confidence
Interval
Lower
Bound
Upper
Bound
Control Office 1 -1.87000 .83992 .156 -4.1233 .3833
Office 2 -3.22000(*) .83978 .001 -5.4729 -.9671
Office 3 -2.01000 .79121 .072 -4.1294 .1094
Office 1 Control 1.87000 .83992 .156 -.3833 4.1233
Office 2 -1.35000 .96806 .658 -3.9470 1.2470
Office 3 -.14000 .92624 1.000 -2.6252 2.3452
Office 2 Control 3.22000(*) .83978 .001 .9671 5.4729
Office 1 1.35000 .96806 .658 -1.2470 3.9470
Office 3 1.21000 .92611 .720 -1.2749 3.6949
Office 3 Control 2.01000 .79121 .072 -.1094 4.1294
Office 1 .14000 .92624 1.000 -2.3452 2.6252
Office 2 -1.21000 .92611 .720 -3.6949 1.2749
* The mean difference is significant at the .05 level.

48

Correlation
There was a strong correlation between antero-posterior incisor position and forehead
inclination in the control group (R
2
= 0.641). There was a poor correlation in Office 1
(R
2
= 0.301), Office 2 (R
2
= 0.019), and Office 3 (R
2
= 0.161). (Figures 14a-d).
Figure 14a: Control Group (AP versus Inclination)

Figure 14b: Office 1 (AP versus Inclination)

y = 2.027x + 8.561
R² = 0.641
0
5
10
15
20
25
30
-2 -1 0 1 2 3 4 5 6 7 8
Control Group: Antero-posterior Incisor (mm) versus
Forehead Inclination (degrees)
y = 0.590x + 15.16
R² = 0.301
0
5
10
15
20
25
30
-10 -5 0 5 10 15
Office 1: Antero-posterior Incisor (mm) versus
Forehead Inclination (degrees)
49

Figure 14c: Office 2 (AP versus Inclination)

Figure 14d: Office 3 (AP versus Inclination)

y = 0.180x + 16.88
R² = 0.019
0
5
10
15
20
25
30
-8 -6 -4 -2 0 2 4 6 8 10 12
Office 2: Antero-posterior Incisor (mm) versus Forehead
Inclination (degrees)
y = 0.355x + 15.56
R² = 0.161
0
5
10
15
20
25
30
-10 -5 0 5 10 15
Office 3: Antero-posterior Incisor (mm) versus Forehead
Inclination (degrees)
50

Incisor Position Relative to Superion, FFA point and Glabella
Figure 15a: Control Group

Figure 15b: Office 1

In figure 15a, control group, 93%
of faces measured had the labial
surface of the maxillary central
incisor fall in between the ideal
FFA point and glabella point. 4%
of incisors measured were
between superion point and FFA
point. 3% of incisors measured
were anterior to glabella point
In figure 15b, Office 1, 22% of
faces measured had the labial
surface of the maxillary central
incisor fall in between the ideal
FFA point and glabella point. 60%
of incisors measured were
between superion point and FFA
point. 18% of incisors measured
were anterior to glabella point
51

Figure 15c: Office 2

Figure 15d: Office 3

In figure 15c, Office 2, 30% of
faces measured had the labial
surface of the maxillary central
incisor fall in between the ideal
FFA point and glabella point. 54%
of incisors measured were
between superion point and FFA
point. 16% of incisors measured
were anterior to glabella point
In figure 15d, Office 3, 30% of
faces measured had the labial
surface of the maxillary central
incisor fall in between the ideal
FFA point and glabella point. 50%
of incisors measured were
between superion point and FFA
point. 20% of incisors measured
were anterior to glabella point
52

Reliability
To test the reliability of the measurements, 10 patients were randomly selected and their
images re-measured by the same examiner after a week interval. Statistical analysis of the
difference between the duplicate measurements was conducted by deriving the Intraclass
Correlation Coefficient (Table XIV, XV). ICC for AP was 1.000 and for Inclination was
0.997, these indicate highly reliable data. In the orthodontic literature errors of less than
0.5mm are considered to be the standard of reliability. No measurement in this study
showed an error greater than 0.5mm, therefore, it can be assumed that the data obtained
are highly reliable. As it relates to angular measurements, reported error measurements
of 2 degrees are reliable. All of the measurements here showed an error less than 0.5
degrees.
Table XIV: Intraclass Correlation for Antero-Posterior Measures

Intraclass Correlation
95% Confidence Interval
Lower Bound Upper Bound
Single Measures 1.000 1.000 1.000

Table XV: Intraclass Correlation for Forehead Inclination

Intraclass Correlation
95% Confidence Interval
Lower Bound Upper Bound
Single Measures .997 .988 .999

53

Chapter 6: Discussion
If the maxillary incisors are considered as part of the overall face, then
orthodontists should evaluate the profile not only from a resting position but from a
smiling position as well. Facial landmarks such as the lips, chin and nose are not as
reliable in assessing overall esthetics when the teeth cannot be displayed in profile [76].
The results of this study confirm Andrews‘ study that the forehead can be used as a
reliable landmark in determining facial harmony. Using the forehead as a primary
landmark for anteroposterior (AP) incisor positioning avoids the potential reliability
issues of traditional cephalometric analyses and repose soft tissues analyses [3].
The purpose of this study was two-fold, in not only confirming Andrew‘s Element
II analysis [54], qualifying a relationship between forehead inclination and maxillary
incisor position when looking at facial harmony, but also comparing his control sample to
a larger study sample in order to reaffirm his findings. In Andrews‘ study (2008), he
found the AP positions of the maxillary central incisors to be strongly associated with the
forehead landmarks and strongly correlated with forehead inclination in adult white
females with good facial harmony (control sample, Figure 14a). His study sample,
comprised of adult white females seeking orthodontic treatment at his office, exhibited
characteristics completely different from the control sample, lacking harmony between
incisor and forehead landmarks [3].
In our study, the study sample was comprised of adult white females from three
separate offices and from different geographic locations. Looking specifically at AP
position of the maxillary central incisors relative to FFA point, there were no significant
54

differences between the three offices, showing that the three offices were similar in this
physical trait (Table IV). There were however significant differences between each
office and the control sample, which was in agreement with Andrews‘ findings (Table
Va-IXb). Therefore in people with facial harmony, there is a balance between central
incisor position and Andrews‘ forehead landmarks, however in most patients seeking
orthodontic treatment, there is lack of balance. For patients seeking orthodontic
treatment, orthodontists can use the Element II analysis to establish goals on where to
ideally position the upper incisor in regards to the face as a whole.
Forehead inclination between the offices did not follow the same pattern as the
AP position of the maxillary incisor. There was only a significant difference between the
control and office 2 (p=0.001, Table XIII). There were no significant differences
between any of the offices, and between the offices and the controls. Due to the fact the
patients are all Caucasian adult females, it was expected for all samples to have similar
forehead shapes, with minor variations. However, office 2, patients from Texas, had a
significant difference from the controls. This can possibly be due to the fact that
Caucasian people from Texas have different sources of ancestry. Since each office was
comprised of patients from distinctly different areas, it is possible for the forehead
inclination in patients of one office to have variation from another. Andrews in fact
acknowledges the existence of three general types of forehead shapes: straight, angular
and rounded. There are also studies called craniofacial anthropometry, which assess
craniofacial features distinct to different ethnicities. Farkas, et al. looked at 14
anthropometric measurements, including forehead measurements, and found significant
55

differences in anthropometric measurements depending on ethnic background [78].
Andrews recognizes the distinctness of facial features in different ethnicities, and
therefore in the Element II analysis, the focus is on establishing a harmony between the
existing forehead inclination and the upper incisor, manipulating the position of the upper
incisor as the forehead is an established part of the face. Therefore, according to
Andrews, each patient has a harmonic incisor position that is specific for their face.
In looking at the correlation of AP incisor position relative to FFA point and
forehead inclination, only the control group exhibited a strong correlation (R
2
= 0.641,
Figure 14a) while there were weak correlation in the three offices (R
2
= 0.301, R
2
=
0.019, R
2
= 0.161, Figure 14b-d) despite the fact that forehead inclination was not found
to be statistically different between the control samples and offices, minus office 2. This
was also in agreement with Andrews‘ study. Harmonious profiles have the upper incisor
positioned ideally, according to the Element II analysis, relative to their forehead
landmarks. The study samples, however, do not have the upper incisor positioned
ideally. Also a distribution of the AP maxillary incisor positions relative to the forehead
landmarks was made for the control sample and each of the three study samples (Figures
15a-d). Most of the patients in each office (Office 1 = 60%, Office 2 = 54%, Office 3 =
50%) had maxillary central incisors positioned posterior to the forehead‘s FFA point,
compared with only 4% of the controls. The patients in each office (Office 1 = 18%
Office 2 = 16%, Office 3 = 20%) were also more likely to have maxillary central incisors
anterior to glabella than those in the control sample (3%). The most esthetic maxillary
central incisor position, between FFA point and glabella, was highest in the control
56

sample (94%), but much less in the three offices (Office 1 = 22%, Office 2 = 30%, Office
3 = 30%).
The findings from this study not only reaffirm Andrews‘ findings, but can be
incorporated into routine orthodontic record taking, diagnosis and treatment planning.
The American Board of Orthodontics requires three extraoral photographs, but a lateral
smiling photograph is not included in that requirement. The inclusion of a smiling profile
photograph with the forehead and maxillary incisors fully visible to the set of diagnostic
records as well as clinical evaluation of the smiling facial profile will allow the
orthodontist to document orientation of the patients‘ maxillary central incisors to the
forehead. Other soft tissue analyses such as Spradley‘s soft tissue points and
McNarama‘s facial angles, and Arnett‘s 19 facial keys are detailed, however require more
extensive measurements, take longer to perform, and do not look at relating the soft tissue
points to hard tissue landmarks [26, 50, 52]. Using Andrews‘ analysis, assessing the
patient from profile with the incisors showing can be useful in providing goals for
maxillary incisor positioning to create facial harmony. Treatment goals for adult white
females should include the maxillary central incisors positioned between the FFA point
and glabella, and correlated with forehead inclination.
The analysis is unique because treatment goals are based off of the patient‘s
existing features, and therefore treatment is directed at maximizing each individuals
esthetic potential by creating a balance and harmony within all areas of the face. It is a
quick and simple way to analyze a critical soft tissue landmark (forehead) and hard tissue
landmark (maxillary central incisor). Generic norms are not created and specified to a
57

patient but contrastingly each individual patient is assessed and given an ideal norm
specific to them. Additional studies that would be needed to extend these findings would
be to look at other races, specific age groups as well as gender groups.

58

Chapter 7: Assumptions
1. The patient pool from the three offices was representative of the general
Caucasian adult female population in the United States.
2. Every patient had no previous orthodontic treatment.
3. All lateral profile smiling images were properly adjusted to Natural Head
Position.
4. All photographs from each office were taken by the same individual in that office.
5. Measurements were accurate and reproducible.

59

Chapter 8: Limitations
1. Small sample size from each office (50) compared to control sample (94).
2. The age range (18-50 yo) for adult patients was too broad.
3. ―Caucasian‖ patients were selected however there was no history of ancestry.
4. Measurements were subjected to human error.

60

Chapter 9: Summary
 There was a significant difference in anteroposterior position of maxillary central
incisor between each of the three offices and the control sample.
 There were no significant differences in anteroposterior position of maxillary central
incisor between each of the three offices.
 There were no significant differences in forehead inclination between Office 1 and
the control sample as well as Office 3 and the control sample.
o There was a significant difference in forehead inclination between Office 2
and the control sample.
 There were no significant differences between forehead inclination between each of
the three offices.
 There was a strong correlation between Forehead Inclination and Anteroposterior
position of Maxillary Incisor in the control sample and a weak correlation in the three
offices.
 The most esthetic maxillary central incisor position, between FFA point and glabella,
was highest in the control sample (94%), but much less in the three offices (Office 1
= 22%, Office 2 = 30%, Office 3 = 30%).
 Most of the patients in each office (Office 1 = 60%, Office 2 = 54%, Office 3 = 50%)
had maxillary central incisors positioned posterior to the forehead‘s FFA point,
compared with only 4% of the controls.
61

 The patients in each office (Office 1 = 18% Office 2 = 16%, Office 3 = 20%) were
also more likely to have maxillary central incisors anterior to glabella than those in
the control sample (3%).

62

Chapter 10: Conclusions
Traditional cephalometrics in orthodontics will continue to be a major tool in
diagnosis and treatment planning, however it cannot become the only means. The goal of
the orthodontist must be not only for bite correction and an esthetic smile but integrating
this correction with overall facial harmony. Andrews‘ Element II analysis integrates
dental correction with facial esthetics. Whereas previous soft tissue analyses have looked
at soft tissue alone in detail, this diagnostic approach is unique because it relates a critical
soft tissue landmark (forehead) with a critical hard tissue landmark (maxillary central
incisor). It is also a quick and simple way to assess an orthodontic photo and determine
esthetic harmony and establish profile goals. This study in particular, makes clear the
usefulness of including a lateral smiling photo for diagnostic purposes. The forehead can
be confirmed as a reliable landmark for assessing the facial profile for adult white
females as it relates to AP maxillary central incisor position. Treatment goals should
include a harmonious AP relationship between the maxillary central incisors and the
forehead for adult white female patients.

63

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Abstract (if available)

Abstract Background: Facial esthetics is an important motivating factor for many patients seeking orthodontic treatment. Traditionally in orthodontics, facial profiles have been evaluated using cephalometrics and repose soft-tissue analysis. In this study we want to evaluate the significance of the profile soft-tissue analysis when the patient is smiling.

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Asset Metadata

Creator Lee, Samuel (author)

Core Title The relationship of the forehead to the maxillary central incisor in adult white females: an evaluation of Andrews Element II analysis

School School of Dentistry

Degree Master of Science

Degree Program Craniofacial Biology

Publication Date 03/03/2011

Defense Date 02/18/2011

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

Tag OAI-PMH Harvest,orthodontic profile analysis

Language English

Contributor Electronically uploaded by the author (provenance)

Advisor Sameshima, Glenn T. (committee chair), Enciso, Reyes (committee member), Paine, Michael (committee member)

Creator Email leesamue@usc.edu,samonotone@gmail.com

Permanent Link (DOI) https://doi.org/10.25549/usctheses-m3681

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