Department of Orthodontics and Pediatric Dentistry, University of Michigan, Ann Arbor, MI, USA.
Department of Orthodontics and Pediatric Dentistry, University of Michigan, Ann Arbor, MI, USA.
Int J Oral Maxillofac Surg. 2019 Jun;48(6):739-745. doi: 10.1016/j.ijom.2019.01.004. Epub 2019 Feb 1.
The aim of this study was to quantify three-dimensional condylar displacements as a result of two-jaw surgery for open bite correction in patients with skeletal class II and class III malocclusion. Pre-surgical (T1) and post-surgical (T2) cone beam computed tomography scans were taken for 16 patients with skeletal class II (mean age 22.3±9.47years) and 14 patients with skeletal class III (mean age 25.6±6.27years). T2 scans were registered to T1 scans at the cranial base. Translational and rotational condylar changes were calculated by x,y,z coordinates of corresponding landmarks. The directions and amounts of condylar displacement were assessed by intra- and inter-class Mann-Whitney U-test or t-test. Class II patients presented significantly greater amounts of lateral (P=0.002) and inferior (P=0.038) translation than class III patients. The magnitudes of condylar translational displacements were small for both groups. Skeletal class III patients had predominantly medial (P=0.024) and superior (P=0.047) condylar translation. Skeletal class II patients presented greater condylar counterclockwise pitch (P=0.007) than class III patients. Two-jaw surgery for the correction of open bite led to different directions and amounts of condylar rotational displacement in patients with skeletal class II compared to class III malocclusion, with greater rotational than translational displacements.
本研究旨在定量分析骨性 II 类和 III 类错[牙合]患者双颌手术治疗开[牙合]后髁突的三维位移。对 16 例骨性 II 类（平均年龄 22.3±9.47 岁）和 14 例骨性 III 类（平均年龄 25.6±6.27 岁）患者进行术前（T1）和术后（T2）锥形束 CT 扫描。T2 扫描以颅底为基准与 T1 扫描配准。通过相应标志点的 x、y、z 坐标计算髁突的平移和旋转变化。采用组内和组间 Mann-Whitney U 检验或 t 检验评估髁突位移的方向和程度。与 III 类错[牙合]患者相比，II 类错[牙合]患者的髁突侧向（P=0.002）和下方（P=0.038）平移量显著更大。两组患者髁突平移位移的幅度均较小。III 类错[牙合]患者的髁突主要表现为内侧（P=0.024）和上方（P=0.047）平移。与 III 类错[牙合]患者相比，II 类错[牙合]患者的髁突逆时针旋转（P=0.007）更为明显。双颌手术治疗开[牙合]导致骨性 II 类错[牙合]患者与骨性 III 类错[牙合]患者的髁突旋转位移方向和程度不同，旋转位移大于平移位移。
