Evaluation of skeletal stability after BSSRO in skeletal class III with anterior open bite

Rim, Jae Suk; Kwon, Jong Jin; Jang, Hyon Seok; Son, Hyoung Min; Nam, Young Won; Choi, Chul Min

Abstract

The purpose of this study is to assess the postoperative stability and the tendency of relapse after both sagittal split ramus osteotomy in skeletal class III with anterior open bite. This retrospective study was based on the examination of 15 patients, 6 males and 9 females, with a mean age 23.1 years. The patients were divided into two groups based on the amount of preoperative overbite(group I:<1mm, group II:> OR = 1mm). Serial lateral cephalometric radiographs were taken within 2 weeks preoperatively, within 1 week postoperatively and at a follow up period that ranged from 7 to 24 months postoperatively. All cephalometric radiographs were traced and digitized using the Quick ceph image Pro for analysis. And then, horizontal and vertical changes of reference points(B point, Pogonion, L1) were assessed by the linear measurements in millimeters on both axes. The results were as follows: 1. Mean horizontal relapses were 0.67+/-0.93mm (11%) at B point (P<0.05) and 0.81+/-1.01mm (13.2 %) at Pogonion (P< .01). 2. Mean vertical relapses were 0.63+/-1.62mm (33.3%) at B point and 0.53+/-1.95mm (31.4%) at Pogonion (P>0.05). 3. The mean angular change of occlusal plane to SN was 0.24+/-1.19 (P>0.05) and that of mandibular plane to SN was 1.03+/-1.85 (P<0.05). 4. There was correlation between the extent of preoperative overbite and the postsurgical relapse at B point and Pogonion. 5. There was no correlation between the amount of surgically produced horizontal movement and the postoperative horizontal relapse at B point.