Date of Award

2021

Document Type

Thesis

Degree Name

Master of Science in Dentistry

Department

Orthodontics

College

College of Dental Medicine

First Advisor

Timothy J. Tremont

Second Advisor

Loring Ross

Third Advisor

Kinon Lecholop

Fourth Advisor

Pinar Emecen-Huja

Fifth Advisor

Ildeu Andrade

Abstract

Introduction: This study investigated an optimal anteroposterior (AP) position of maxillary incisors displayed in a smiling profile in Caucasian males relative to Glabella Vertical (GV). The study also assessed any difference in preferred AP incisor position between orthodontists and laypersons, among orthodontists in various years of practice, among laypersons in various age groups, and between genders of orthodontists and laypersons. Methods: Existing smiling profile photographs of 40 Caucasian males, ages 15 to 60, were retrospectively collected from the Medical University of South Carolina (MUSC) Department of Orthodontics database. Photographs were numerically randomized and uploaded into a Research Electronic Data Capture (REDCAP) survey. Seventy-one orthodontists and forty-six laypersons age 18 and older responded to the survey having assessed the AP incisor position in each profile photograph as: 1) too far forward, 2) too far back, or 3) just about right, which were considered Group F, Group B, Group 0, respectively. Orthodontists were divided into five groups based on years in practice. Laypersons were divided into three groups based on age. Results: An optimal group (Group 0) was constructed based on incisor AP position rated "just about right "from 70% of all judges. Group O yielded a mean maxillary incisor to GV of -1.5mm. Mean maxillary incisor to GV measurement for orthodontists was -1.1 mm, while the measurement for laypersons was -2.4mm. The "too far back" group (Group B) was similarly developed with the same 70% threshold. Mean maxillary incisor to GV was -5.8mm for orthodontists and -6.lmm for laypersons. There was insufficient agreement (below 70%) for the "too far forward" group (Group F) to conduct a similar analysis. Results indicate the mean GV for 'just about right," "too far forward," and "too far back" groups are statistically different for both orthodontists (p<0.05) and laypersons (p<0.05). There were no differences in ratings by orthodontists based on years in practice, by laypersons based on age groups, or between genders of orthodontists and laypersons. Conclusions: Among orthodontists and laypersons combined, the optimal AP maxillary incisor position in Caucasian males was found to be 1.5mm behind GV. Orthodontists rated the optimal AP maxillary incisor position as 1.1mm behind GV, while laypersons rated the optimal AP maxillary incisor position as 2.4mm behind GV. While statistically significant, the difference was only 1.3mm. There were no differences in AP ratings among orthodontists based on years in practice, among laypersons based on age group, or between genders of orthodontists and laypersons. GV may be a useful landmark for assessing the AP position of the maxillary incisor in Caucasian males.

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