RESUMO
Orthognathic surgery for Class III malocclusion requires an elaborate preoperative planning using cephalometries or Mock surgery models which enable the surgeon to anticipate postoperative skeletal changes of maxilla and mandible as well as dentition. After surgery, patient's satisfaction is greatly influenced by appearance of soft tissue change. Therefore, it is imperative to predict a relatively accurate soft tissue change prior to surgery. A 5 year retrospective study was designed to evaluate the soft tissue change after sagittal split osteotomy of ramus(SSRO) for class III malocclusion. Analyses of preoperative and postoperative anthropometric measurements were performed. Patients who were treated only by SSRO for class III malocclusion and could follow up for 6 months were studied. Among them, the patients who had history of cleft palate and lip or hemifacial microsomia were excluded. Soft tissue changes were estimated by using the frontal and lateral photographs. Skeletal changes were observed by measuring amount of set back and angular changes of mandible to the reference line by using cephalometries. Relapses were also measured 6 months after the operation. We could observe skeletal changes were more profound than soft tissue changes concerning amount of set back, but soft tissue changes were also profound in angle. Relapse was more profound in skeleton than soft tissue but the amount was not significant. In spite of the variables which may affect proper assessment of the soft tissue change after skeletal relocation, this study can serve as a guide for exact prediction of the postoperative change of soft tissue and skeleton.