Abstract:

Objective The location features of adult skeletal class Ⅲ malocclusion mandibular deviation patients with mandibular condyle using Mimics software for 3D measurement. Methods    Fifty patients with skeletal class Ⅲ malocclusion and mandibular deviation（deviation group：28 patients，nondeviation group：22 patients）received spiral computed tomography，DICOM data were collected. Maxillary and mandibular three-dimensional reconstruction was performed using Mimics 17.0. The upper and lower jaws were separated and the condylar morphology was revealed completely. To make sure measurements and analyze statistically. Results    There was no statistical difference in nondeviation group. In deviation group，the angle of coronal and horizontal plane in deviated condyle with coronal plane in skull was larger than the other side；the angle of horizontal plane in condyle with FH plane was smaller than the other side. The distance of sigmoid notch to FH plane and coronal plane was smaller than the other side. The distance of sigmoid notch to midsagittal plane is larger than the other side. The other measurements had no satistical difference. Conclusion    Mandibular condyle position of adults with skeletal class Ⅲ malocclusion and mandibular deviation is asymmetric. The lateral condyle is more laterally and inferiorly positioned on the contralateral side than on the deviated side. The sigmoid notch is more laterally，superiorly，and posteriorly positioned on the deviated side. There is no obvious change in the TMJ space.

Key words: skeletal class Ⅲ malocclusion, mandibular asymmetry, condyle, CT

摘要：

目的    利用Mimics软件对成人骨性Ⅲ类错牙合伴下颌偏斜患者下颌骨髁突的位置特征进行三维测量。方法    对50例骨性Ⅲ类错牙合畸形患者（18～34岁）的颅面部进行螺旋CT扫描（偏斜组28例，非偏斜组22例）， 采集DICOM数据，利用Mimics17.0软件对骨组织进行三维重建并建立三维坐标系，分离上下颌骨，显露完整的髁突形态，确定标志点及测量相关参考平面，对结果进行统计学分析。结果    非偏斜组两侧测量值差异无统计学意义。偏斜组中，偏斜侧髁突的冠状面和水平面与颅骨冠状面交角均大于对侧，髁突水平面与眼耳平面交角小于对侧，髁突矢状面与眼耳平面交角大于对侧，乙状切迹到眼耳平面和冠状面距离均小于对侧，到正中矢状面距离大于对侧。其余结果差异无统计学意义。结论    骨性Ⅲ类错牙合伴下颌偏斜患者的髁突位置不对称。偏斜侧髁突位置相对关节窝向后、内旋转，乙状切迹向后、上、外旋转。偏斜对侧髁突位置相对关节窝向前、外旋转，乙状切迹向前、下、内旋转。左右侧关节间隙无明显差异。

关键词: 骨性Ⅲ类错牙合, 下颌偏斜, 髁突, CT