Chung Il-Hyuk, Yoo Chung-Kyu, Lee Eun-Kyung, Ihm Jong-An, Park Chang-Joo, Lim Ji-Sun, Hwang Kyung-Gyun
Department of Dentistry/Oral and Maxillofacial Surgery, Seoul National University Boramae Hospital, Seoul, Korea.
J Oral Maxillofac Surg. 2008 Mar;66(3):446-52. doi: 10.1016/j.joms.2007.06.643.
This comparative study was performed to analyze mandibular stability after bilateral sagittal split ramus osteotomies for a mandibular setback with a monocortical plate fixation or bicortical screw fixation.
A total of 60 patients with a skeletal Class III malocclusion who underwent sagittal split osteotomies and mandibular setback were included in the present study. Among the patients, 30 were osteosynthesized monocortically with a titanium plate, while the other 30 were osteosynthesized bicortically with positioning screws. This retrospective study used cephalometric radiographs taken preoperatively (T0), and at 1 week (T1), 3 months (T2), and 1 year (T3) postoperatively. The linear and angular changes of the cephalometric landmarks of the chin region were measured at each time period, and the changes of each cephalometric landmark were determined for 4 different time intervals: T0 to T1 (Delta T1), T1 to T2 (Delta T2), T2 to T3 (Delta T3), and T0 to T3 (Delta T4). Postoperative changes in mandibular shape were analyzed using a paired t test to determine the stability of fixation methods.
The surgical changes (Delta T1) could be characterized as posterior movements of the mandibular body and posterosuperior movements of the chin landmark. The results of the cephalometric analysis at 3 and 12 months postsurgery (Delta T2 and Delta T3) could be characterized as anterosuperior movements of the mandible. In both treatment groups, surgical changes were relatively well maintained. Likewise, analysis of the horizontal and vertical movements of the chin landmarks indicated a similar tendency in both groups. There were no statistically significant differences between the measurements of postoperative changes at each time period after surgery.
The findings of our study suggest that there were no significant differences in postoperative changes in mandibular shape in both the monocortical and bicortical fixation groups after sagittal split ramus osteotomy. We concluded that monocortical osteosynthesis using a miniplate could be used to obtain stable postoperative changes after mandibular setback.
本对比研究旨在分析采用单皮质板固定或双皮质螺钉固定进行双侧矢状劈开下颌支截骨术后退下颌后下颌的稳定性。
本研究纳入了60例接受矢状劈开截骨术和下颌后退术的骨性III类错牙合患者。其中，30例采用钛板进行单皮质骨固定，另外30例采用定位螺钉进行双皮质骨固定。这项回顾性研究使用了术前（T0）、术后1周（T1）、3个月（T2）和1年（T3）拍摄的头影测量X线片。在每个时间段测量颏部区域头影测量标志点的线性和角度变化，并确定4个不同时间间隔内每个头影测量标志点的变化：T0至T1（ΔT1）、T1至T2（ΔT2）、T2至T3（ΔT3）以及T0至T3（ΔT4）。使用配对t检验分析术后下颌形态的变化，以确定固定方法的稳定性。
手术变化（ΔT1）的特征为下颌体向后移动以及颏部标志点向后上移动。术后3个月和12个月的头影测量分析结果（ΔT2和ΔT3）的特征为下颌向前上移动。在两个治疗组中，手术变化相对保持良好。同样，颏部标志点水平和垂直移动的分析表明两组有相似趋势。术后各时间段的术后变化测量之间无统计学显著差异。
我们的研究结果表明，矢状劈开下颌支截骨术后，单皮质和双皮质固定组下颌形态的术后变化无显著差异。我们得出结论，使用微型钢板进行单皮质骨固定可用于在下颌后退术后获得稳定的术后变化。
