하악전돌증 환자에 있어서 악교정수술 전후의 하악각 변화에 관한 임상적 연구

A CLINICAL STUDY OF CHANGES IN GONIAL ANGLE BETWEEN PRE- AND POST-ORTHOGNATHIC SURGERY IN MANDIBULAR PROGNATHIC PATIENTS

The main goal of the surgical treatment of maxillofacial deformity is improved esthetic appearance and masticatory function. Recently, the purpose of orthognathic surgery has been focused on esthetic improvement of the patients. The purpose of this study was to investigate the changes in gonial angle to orthognathic surgery. For this study 30 patients were randomly selected. All patients with mandibular prognathism were operated upon with bilateral sagittal split ramus osteotomy and mandibular setback. The patients were cephalmetric lateral radiographs for 1 hear. Lateral cephalmetric radiographs taken preoperatively, over 6-months and 1 year follow up were traced and analysed. The following conclusions were reached. : 1. During following up period for 1 year, the change of gonial angle after orthognathic surgery was decreased, except 3 cases. The mean gonial angle change was decreased from 128.6°(±4.83) to 123.4°(±5.52) in female(p<0.05). 2. During follow up period for 1 year, the mean gonial angle was decreased after orthognathic surgery from 129.7°(±6.47) to 123.3°(±7.52), in all male patients(p<0.05). 3. The mean gonial angle changes after orthognathic surgery was about 5.2°in female and 5.4°in male. There was less statistical significance between male and female. 4. The ratio of mandibular setback amount from 6mm to 15mm was 83.3%, and from 1mm to 5mm was 10%.