The Role of Facial Attractiveness in Borderline Cases of Dental Attractiveness Judged by IOTN ...

98 Pages·2016·1.21 MB·English

The Role of Facial Attractiveness in Borderline Cases of Dental Attractiveness Judged by
IOTN

THESIS

Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in
the Graduate School of The Ohio State University

By
Elizabeth K. Johnson
Graduate Program in Dentistry

The Ohio State University
2016

Master's Examination Committee:
Dr. Henry W. Fields, Jr., Advisor
Dr. F. Michael Beck
Dr. Allen R. Firestone
Dr. Stephen F. Rosenstiel
Copyrighted by
Elizabeth K. Johnson
2016
Abstract

Previous eye-tracking research has demonstrated that laypersons view the range
of dental attractiveness levels differently depending upon facial attractiveness levels.
How the borderline levels of dental attractiveness are viewed has not been evaluated in
the context of facial attractiveness and compared to those with near ideal esthetics or
those in definite need of orthodontic treatment according to the AC- IOTN scale.
Objective: To determine the level of viewers’ visual attention in the borderline AC-
IOTN treatment need category (levels 3-7) for individuals considered “attractive,”
“average attractiveness,” or “unattractive.” Methods: Facial images of individuals of
three different facial attractiveness levels were combined with 5 levels of dental
attractiveness (dentitions representing AC-IOTN levels 3,4,5,6, and 7) using imaging
software to form 30 composite images. Each image was viewed twice by 66 lay
participants utilizing eye-tracking. Both the fixation density (number of fixations per
facial area) and fixation duration (duration for each facial area) were quantified for each
image viewed. Repeated-measures ANOVA was used to determine how fixation density
and duration varied among six facial interest areas (chin, ear, eye, mouth, nose, and
other). Results: Viewers demonstrated excellent to good reliability among the six
interest areas (intraviewer reliability: 0.70 to 0.96; interviewer reliability: 0.56-0.93).
ii
Between IOTN 3 and 7 there was a trend for viewers of all facial attractiveness levels to
show an increase in attention to the mouth. However, only with the attractive models
were significant differences in fixation density and duration found between borderline
levels with female viewers. Female viewers attended to different areas of the face than
male viewers. Conclusions: The importance of dental attractiveness is amplified in
facially attractive female models compared with average attractive and unattractive
female models between near ideal to borderline-severe dentally unattractive levels.

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Acknowledgments

I wish to thank the following people:
-Drs. Fields, Beck, Firestone, and Rosenstiel for their guidance and advice in the
production of this Master’s Thesis
-Dr. Ian Krajbich for very generously allowing our team to use his eye tracker
-Sam Hutton for all of his technical assistance and for saving me hours of time with data
entry
-My research associates, Tori Hutta and Adam Swan for helping to define interest areas,
recruit participants, and run the eye tracking experiment
-Mike Fields, for helping me in the construction of the composite images in Photoshop
-My husband, Steve, and the rest of my family for providing much support and
understanding during this process
-Drs. Robin Baker and Mike Richards, who were previously familiar with eye tracking
and were able to help me get started and provide support along the way
-My co-residents for their endless encouragement
-The Delta Dental Master’s Thesis Reward Program for their financial support of this
project
-Lastly, the many eye-tracking participants who gave their time and attention to my study

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Vita

June 1997 .......................................................Upper Arlington High School
May 2001 .......................................................B.A. Zoology, Miami University
June 2006 .......................................................D.D.S. The Ohio State University
March 2016 ...................................................M.S. Orthodontics, The Ohio State
University

Publications

Crawford B, Kim DG, Moon E, Johnson E, Fields HW, Palomo JM, Johnston WM.
Cervical vertebral bone mineral density changes in adolescents during orthodontic
treatment. Am J Orthod Dentofacial Orthop 2014;146(2):183-9.

Fields of Study

Major Field: Dentistry
Specialty: Orthodontics

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Table of Contents

Abstract ............................................................................................................................... ii
Acknowledgments.............................................................................................................. iv
Vita ...................................................................................................................................... v
List of Tables .................................................................................................................... vii
List of Figures .................................................................................................................... ix
Chapter 1: Introduction ...................................................................................................... 1
Chapter 2: Materials and Methods ................................................................................... 14
Chapter 3: Manuscript...................................................................................................... 23
Chapter 4: Conclusions .................................................................................................... 51
Appendix: Tables and Figures ......................................................................................... 52
Complete References ........................................................................................................ 79

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List of Tables

Table 1. Combinations of composite images ................................................................... 56
Table 2. Reliability. Total density and duration of fixations by area of the face;
reliability is designated as follows: <0.20 poor, 0.21-0.40 fair, 0.41-0.60 moderate, 0.61-
0.80 good, and > 0.80 excellent;67 LCB, lower confidence boundary; UCB, upper
confidence boundary ......................................................................................................... 56
Table 3. ANOVA summaries. A, total fixation duration; B, maximum fixation density
........................................................................................................................................... 57
Table 4. Mean total duration and standard deviations of fixations by rater sex (RSEX),
facial attractiveness level (ATRACT), dental attractiveness level (OCCLSN), and interest
area (CN=chin, ER=ear, EY=eye, MO=mouth, NO=nose, OR=other). ATT, attractive;
AVG; average attractive; UNATT, unattractive ............................................................... 58
Table 5. Mean maximum density and standard deviations of fixations by rater sex
(RSEX), facial attractiveness level (ATRACT), dental attractiveness level (OCCLSN),
and interest area (CN=chin, ER=ear, EY=eye, MO=mouth, NO=nose, OR=other). ATT,
attractive; AVG, average attractive; UNATT, unattractive .............................................. 64
Table 6. Significant differences between levels of dental attractiveness for fixation
duration for male viewers. Significant differences (p < 0.05) are represented by
discrepancies in letters between each dental attractiveness level (IOTN) for each of the
facial attractiveness and interest area combinations. Across a row, levels which differ
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significantly do not share the same alphabetical letter. *Indicates the row where
significant differences exist .............................................................................................. 70
Table 7. Significant differences between levels of dental attractiveness for fixation
duration for female viewers. Significant differences (p < 0.05) are represented by
discrepancies in letters between each dental attractiveness level (IOTN) for each of the
facial attractiveness and interest area combinations. Across a row, levels which differ
significantly do not share the same alphabetical letter. *Indicates the row where
significant differences exist .............................................................................................. 70
Table 8. Significant differences between levels of dental attractiveness for fixation
density for male viewers. Significant differences (p < 0.05) are represented by
discrepancies in letters between each dental attractiveness level (IOTN) for each of the
facial attractiveness and interest area combinations, thus there are no significant
differences for the male viewers. ...................................................................................... 71
Table 9. Significant differences between levels of dental attractiveness for fixation
density for female viewers. Significant differences (p < 0.05), represented by
discrepancies in letters between each dental attractiveness level (IOTN) for each of the
facial attractiveness and interest area combinations. Across a row, levels which differ
significantly do not share the same alphabetical letter. *Indicates the row where
significant differences exist .............................................................................................. 71

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List of Figures

Figure 1. Example sheet of dental attractiveness images given to raters for comparison
against a standard AC-IOTN level .................................................................................... 72
Figure 2. Examples of composite images ........................................................................ 73
Figure 3. Composite image with demarcation of interest areas. Locations of fixations are
represented by the teal dots ............................................................................................... 74
Figure 4. Example of a participant seated at the table-top eye-tracker for the eye-tracking
session ............................................................................................................................... 74
Figure 5. Mean total duration of fixations for male viewers received by dental
attractiveness level (AC-IOTN level) ............................................................................... 75
Figure 6. Mean total duration of fixations for female viewers received by dental
attractiveness level (AC-IOTN level) ............................................................................... 75
Figure 7. Mean maximum density of fixations for male viewers received by dental
attractiveness level (AC-IOTN level) ............................................................................... 76
Figure 8. Mean maximum density of fixations for female viewers received by dental
attractiveness level (AC-IOTN level) ............................................................................... 76
Figure 9. The continuum of data from this study and Richards et al.19 Mean fixation
duration for female viewers (A) and male viewers (B) for the eye and mouth at each
facial and dental attractiveness level. Same facial attractiveness levels have the same
dash type ........................................................................................................................... 77
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