Date of Graduation

2015

Document Type

Thesis

Degree Type

MS

College

School of Dentistry

Department

Orthodontics

Committee Chair

Tim Tremont

Committee Co-Chair

Richard Jurevic

Committee Member

Chris Martin

Committee Member

Peter Ngan

Abstract

In part I, a sample of pre-treatment lateral cephalograms collected consecutively was analyzed to look for correlation between soft tissue and hard tissue chin measurements. In part II a survey was constructed to investigate the effects of changes in chin prominence on perceived facial profile attractiveness. Materials & Methods: (Part I) 105 cephalograms of patients in the permanent dentition, 12 years old or greater, were analyzed with a series of hard tissue and soft tissue measurements. The sample was also grouped based on skeletal class and category. (Part II) A facial profile photograph was obtained from one female subject. The chin prominence was morphed in 1mm increments forward and backward to create 14 new images (15 total). A second group was created by cropping these 15 images to only include the chin and lower lip. Orthodontists and non-orthodontists were recruited for a survey and asked to rate the attractiveness of both series of images. Results: (Part I) Chin soft tissue thickness, Pog-Pog', showed weak correlation with N-Me (R=0.24), Sn'-Me (R=0.21), Pog'-GALL (-0.42), Pog-GALL (-0.29), and TVL-Pog' (-0.40). There was no significant difference in average chin soft tissue thickness when the sample was grouped by skeletal class or category. (Part II) For the survey, when comparing orthodontist vs. non-orthodontists, there was no significant difference in the ratings of chin profile alone or the whole face profile. When comparing men versus women, there was no significant difference in rating the whole face, but there was significant difference in the ratings of the chin alone. There was also no significant difference when comparing ratings of the chin alone to the corresponding whole face images. Conclusions: 1) There is only weak correlation between chin soft tissue thickness and skeletal measurements. 2) Chin soft tissue thickness is highly variable. 3) There is no difference in soft tissue chin thickness based on skeletal class or category. 4) Perceived attractiveness of the profile is sensitive to millimeter changes in chin prominence. 5) Orthodontists and non-orthodontists agree on attractiveness. 6) Male and females agree on profile attractiveness but differ on chin attractiveness.

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