A comparative study on the degree of relapse following one jaw surgery and two jaw surgery in skeletal Class III patients

Kim, Jeong Rog; Son, Woo Sung

Abstract

The purpose of this study was to investigate the degree of relapse following orthognathic surgery and the relationship between preoperative state and the methods of orthognathic surgery in skeletal Class III patients. Thirty-one patients were selected(17 men, and 14 women) for this study, who had received orthognathic surgery(20 one jaw surgery, and 11 two jaw surgery). The mean age was 22.5 years. Their lateral cephalograms, that were taken preoperatively, immediate postoperatively and follow-up over one year, were traced and analysed. The results were as follows: 1. In two jaw surgery, mandibular length, lower facial height and lower lip length were 4.24mm, 4.64mm and 4.13mm longer than in one jaw surgery, respectively. But in two jaw surgery, overjet was 3.13mm shorter than in one jaw surgery. 2. In one jaw surgery, mandible was moved back 8.95+/-4.45mm at B point. In two jaw surgery, maxilla was moved forward 5.l5+/-3.46mm and mandible was moved back 7.24+/-9.llmm at B point. 3. Between postoperation and follow-up over one year, A point, A' point, Pn and Sn were moved backward 1.02+/-2.14mm, 1.73+/-1.63mm, 1.05+/-1.48mm and 1.55+/-1.37mm in two jaw surgery, respectively. 4. Between postoperation and follow-up over one year, in one jaw surgery, B point was moved forward 2.58+/-4.22mm and B' point was moved forward 1.95+/-4.39mm. In two jaw surgery, B point was moved forward 0.65+/-2.88mm and B' point was moved forward 0.19+/-3.32mm. In one jaw surgery, relapse rate was 28% at B point and 24% at B' point, whereas in two jaw surgery, relapse rate was 8% at B point and 3% at B' point.