Date of Award

Spring 1992

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Dentistry

First Advisor

Ferguson, Donald J.

Second Advisor

Chu, Marissa

Third Advisor

Kittleson, Russell T.

Abstract

The results of mandibular advancement surgery have traditionally been measured on lateral cephalograms. Photogrammetry, or the gathering of data off standardized facial photographs, has in the last few decades been introduced as a reliable way to measure facial dimensions, but use of photographs has been restricted to the the gathering of population norms. This study combined both cephalometric and photogrammetric techniques in the evaluation of mandibular advancement surgery. The sample consisted of 19 patients; two men and seventeen women, ages ranging from 15.2 years to 44.5 years, with a mean age of 29.4 years. The purpose of the study was to examine areas that changed significantly from pre-treatment to posttreatment on both lateral cephalograms and photographs. It was furthermore an aim of the study to compare cephalometric changes with photogrammetric changes. Finally, it was the study's aim to correlate hard tissue changes, as seen cephalometrically, with soft tissue changes, as seen photogrammetrically. The cephalometric analysis used thirty-nine hard and soft tissue angles and distances. The photogrammetric analysis consisted of fifty-one soft tissue angles and distances. Paired t·tests were used to compare pre· and posttreatment values for the cephalometric and photogrammetric analyses. T-tests were used to compare cephalometric change with diagnostically similar photogrammetric change. Correlation tests were performed to see if hard tissue changes as documented on the lateral cephalogram are predictive of soft tissue changes as seen on the photographs. Results showed that twenty-one of thirty-nine cephalometric variables demonstrated statistically significant changes as a result of therapy. Eleven of forty-one photogrammetric variables changed significantly pre- to posttreatment. The profile photograph accurately reflected the changes that took place cephalometrically when diagnostic similar measurements were compared. Five of six variables assessed from the lateral photograph demonstrated the same changes that were shown cephalometrically. None of the correlations of the cephalometric and photogrammetric pairs had a magnitude greater than 0.57, and therefore prediction of photogrammetric change from cephalometric change was not feasible when assessing an individual patient. Two important changes are reflected photogrammetrically which can not be observed cephalometrically; upper lip vermillion border thins out and cheeks become relatively more prominent.

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