Kim Hyung-Mo, Baek Seung-Hak, Kim Tae-Yun, Choi Jin-Young
From the *Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital, †Departments of Orthodontics, and ‡Oral and Maxillofacial Surgery, School of Dentistry, Dental Research Institute, Seoul National University, Seoul, South Korea.
J Craniofac Surg. 2014 Nov;25(6):2002-7. doi: 10.1097/SCS.0b013e3182a246f1.
This study was performed to evaluate the efficacy of computer-aided design/computer-aided manufacturing (CAM/CAD)-made condyle positioning jig in orthognathic surgery. The sample consisted of 40 mandibular condyles of 20 patients with class III malocclusion who underwent bilateral sagittal split ramus osteotomy with semirigid fixation (6 men and 14 women; mean age, 25 y; mean amount of mandibular setback, 5.8 mm). Exclusion criteria were patients who needed surgical correction of the frontal ramal inclination and had signs and symptoms of the temporomandibular disorder before surgery. Three-dimensional computed tomograms were taken 1 month before the surgery (T1) and 1 day after the surgery (T2). The condylar position was evaluated at the T1 and T2 stages on the axial, frontal, and sagittal aspects in the three-dimensional coordinates. The linear change of the posterior border of the proximal segment of the ramus between T1 and T2 was also evaluated in 30 condyles (15 patients), with the exception of 10 condyles of 5 patients who received mandibular angle reduction surgery. There was no significant difference in the condylar position in the frontal and sagittal aspects (P > 0.05). Although there was a significant difference in the condylar position in the axial aspect (P < 0.01), the amount of difference was less than 1 mm and 1 degree; it can be considered clinically nonsignificant. In the linear change of the posterior border of the proximal segment of the ramus, the mean change was 1.4 mm and 60% of the samples showed a minimal change of less than 1 mm. The results of this study suggest that CAD/CAM-made condyle positioning jig is easy to install and reliable to use in orthognathic surgery.
本研究旨在评估计算机辅助设计/计算机辅助制造（CAM/CAD）制作的髁突定位夹具在正颌外科手术中的疗效。样本包括20例III类错牙合患者的40个下颌髁突，这些患者接受了双侧矢状劈开下颌升支截骨术并采用半刚性固定（6名男性和14名女性；平均年龄25岁；平均下颌后缩量5.8 mm）。排除标准为术前需要手术矫正升支前缘倾斜度以及有颞下颌关节紊乱体征和症状的患者。在手术前1个月（T1）和手术后1天（T2）进行三维计算机断层扫描。在三维坐标中，于T1和T2阶段在轴向、额状面和矢状面评估髁突位置。除了5例接受下颌角缩小手术的患者的10个髁突外，还在30个髁突（15例患者）中评估了T1和T2之间升支近心段后缘的线性变化。在额状面和矢状面的髁突位置上没有显著差异（P>0.05）。虽然在轴向的髁突位置有显著差异（P<0.01），但差异量小于1 mm和1度；可认为在临床上无显著意义。在升支近心段后缘的线性变化中，平均变化为1.4 mm，60%的样本显示最小变化小于1 mm。本研究结果表明，CAD/CAM制作的髁突定位夹具在正颌外科手术中易于安装且使用可靠。
