A cephalometric study on changes of facial morphology in the frontal view following mandible setback surgery(bssro) in patients with skeletal class iii dentofacial deformities

Jang, Hyon Seok; Rim, Jae Suk; Kwon, Jong Jin; Lee, Bu Kyu; Son, Hyoung Min

Abstract

PURPOSE: The purpose of this study was to analyze the lower third facial changes in frontal view after mandibular setback surgery.
MATERIALS AND METHODS
In this study, fifteen subjects(6 males and 9 females) with class III dental and skeletal malocclusions who were treated with BSSRO(Bilateral Sagittal Split Ramus Ostetomy) were used. Frontal cephalometric radiographs were taken preoperatively and more than 6 months postoperatively, and hard tissue(H2-H1) and soft tissue changes (S2-S1) were measured on vertical and horizontal reference lines. In 15 cases, changes which developed more than 6 months after surgery were studied.
RESULTS
The results were as follows. 1. In the facial height, hard tissue decreased(2.46+/-2.76mm) with statistical significance(P<0.01), and soft tissue also decreased(1.64+/-3.66mm). As a result, the facial height generally becomes shorter after sagittal split ramus osteotomy. 2. In the mandibular width, hard tissue decreased(2.08+/-3.59mm) with statistical sgnificance(P<0.05), but soft tissue increased(2.14+/-5.73mm) without statistically significant difference(P>0.05) postoperatively. 3. In the facial index, hard tissue decreased(0.23+/-2.21%), but soft tissue increased(2.41+/-3.46%) with statistical significance.
CONCLUSION
One of the main purpose of orthognathic surgery is to achieve facial esthetics and harmony. In order to fullfill this purpose, it is important to carry out a precise presurgical treatment planning by estimating the changes of frontal profile after surgery.