A study on postoperative facial predictions of patients with mandibular prognathism

Abstract

This study was made in order to obtain the post-operative profile image in cases of surgical correction of mandibular prognathic patients for reference.
The equations for predicting X, Y measurements of post-operative soft tissue points were derived by means of stepwise multiple regression on the basis of pre-and post-operative lateral cephalometric data of 100 mandibular prognathic patients (35 males and 65 females) operated on by Obwegeser-Dal Pont method.
The profile lines were drawn by computer graphics, by passing them through the predicted post-operative soft tissue data points on the basis obtained regression equations. Then an attempt was made to prepare predicted post-operative montage photographs taken with a Minolta MONTAGE UNIT 401 P, by superimposing facial standardized photos of patients, which were taken pre-operatively as reference material on the profile lines.
The results obtained are as follows:
1. F values of all equations were significant (p<0.01), and high multiple correlation coefficients were obtained.
2. Hermite Curve was considered to be appropriate for the profile lines drawn by computer graphics, passing through the predicted post-operative soft tissue data points.
3. The author succeeded in preparing post-operative montage photographs very similar to the lateral photos taken 6 months post-operatively. It seems that the clinical application of such montage photos to surgical correction cases will provide useful information for treatment planning.