BSSRO后退矫正下颌发育过度对颞下颌关节的影响

The changes of temporomandibular joint disc position and configuration in orthodontics surgery treatment:a magnetic resonance imaging investigation

目的:采用MRI影像学方法,研究成人骨性Ⅲ类错畸形(简称Ⅲ类畸形)正畸正颌联合治疗后颞下颌关节(TMJ)的盘突关系的空间位置变化。方法:24例下颌发育过度的Ⅲ类畸形患者,采用正畸治疗及双侧下颌支矢状劈开后退术(BSSRO),分别在术前和术后6个月进行MRI检测、头颅定位侧位片以及关节症状记录,比较矫正前后关节症状、关节盘长度以及移位量的变化。采用SPSS11.0软件包进行配对t检验。结果:矫正前有关节弹响的患者3例6侧髁突中,矫正后弹响消失1侧;矫正前关节区有疼痛1例,手术后3个月疼痛消失,术后半年疼痛症状重新出现;治疗前未发现有关节症状者20例,矫正后也未发生。48个关节盘长度测量,矫正前关节盘长度最大12.928mm,最小3.040mm,均数为8.288mm;矫正后关节盘长度最大11.589mm,最小3.699mm,均数为8.097mm。2组均数自身比较,无显著性差异(P>0.05)。关节盘移位测量结果:矫正前关节盘位置最大前移6.090mm,均数为1.383mm;矫正后关节盘位置最大前移11.931mm,均数为2.193mm。2组均数自身比较,无显著性差异(P>0.05)。结论:骨性Ⅲ错畸形可以被正畸正颌联合治疗良好地矫正,达到面形美观和最大牙尖咬合位的效果。正畸正颌联合治疗、下颌骨BSSRO未引起关节盘明显移位和关节盘长度明显改变,但是也未发现正颌正畸联合治疗对TMJ症状有明显的改善作用。

PURPOSE： This study was aimed to evaluate the effects of orthodontics-orthognathic surgery for skeletal Class Ⅲ malocclusion on temporomandibular joint （TMJ） disc position and configuration with magnetic resonance imaging. METHODS： Twenty-four patients with Class Ⅲ dentofacial deformity were studied. The patients treated with preoperative orthodontics, bilateral sagittal split ramus osteotomy （SSRO）, post-operative orthodontics were studied clinically, radiographically and with magnetic resonance imaging （MRI） in two different phases in order to locate the position of the temporomandibular joint （TMJ） disc in relation to the glenoid fossa. The data was analyzed by SPSS11.0 software package for paired t test. RESULTS： Abnormal joint sound disappeared in one of three patients with joint sound before surgery, one patient with pre-operative pain in the joint had no pain after surgery. There were no TMJ symptoms in 20 of 24 patients preoperatively and postoperatively. 48 sagittal magnetic resonance imagings showed the mean disc length was 8.288mm preoperatively, 8.097mm postoperatively, no statistically significant difference was found between the two phases of the study. The mean displacement of the TMJ disc measured was 1.383mm preoperatively and 2.193mm postoperatively with no statistically significant difference （P〉0.05）. CONCLUSION： Skeletal Class Ⅲ malocclusion can be corrected successfully through orthodontic and orthognathic treatment for facial appearance and occlusion. Clinical and magnetic resonance imaging analysis find no significant changes on position of TMJ disc and length of disc after orthognathic surgery. Degenerative joint change is not improved by operation.