Abstract:

Objective    To classify the patients with facial asymmetry deformities by cluster analysis. Methods    Totally 44 patients with facial asymmetry deformity were selected from July 2008 to July 2013 in School and Hospital of Stomatology， China Medical University， the measuring data of three-dimensional craniofacial CT scan were used for statistical analysis， and patients with asymmetry deformities were divided into several categories by cluster analysis. Results    The 44 patients were divided into three categories according to the measurement value of jaws and teeth by clustering analysis. The first category included 16 patients， whose deformities showed that maxilla was in symmetry but the mandibular body translated horizontally；the second category included 17 patients，whose deformities showed that the bilateral ramus were asymmetrical and the maxilla didn’t rotate accordingly； the third category included 11 patients， whose maxilla and mandible showed overall rotational movement. This category deformity showed serious asymmetry and was familiar with hemifacial atrophy. Conclusion    Facial asymmetry can be divided into 3 categories based on the symmetry of body of the mandible and mandibular ramus and whether the maxilla has rotation. It is important for diagnosis and classification of facial asymmetry， preoperative designing and communication among doctors.

Key words: orthognathic surgery, digital technique, asymmetry deformity, three dimensional reconstruction, classification

摘要：

目的    尝试采用聚类分析方法对颜面部不对称畸形患者进行分类。方法    对2008年7月至2013年7月到中国医科大学口腔医学院口腔颌面外科就诊的44例颜面部不对称畸形患者的头颅三维CT数据测量值进行统计学研究，通过聚类分析方法将这些患者进行分类。结果    44例患者根据颌骨及牙齿的测量指标值聚类分析，可分成三大类。第一类16例，占36.4%，为上颌骨基本对称，下颌骨体部水平方向平移，双侧下颌升支与正中矢状面成角对称；第二类25例，占38.6%，为下颌骨双侧升支及下颌骨体部发育不对称，上颌骨未随之发生明显的旋转；第三类11例，占25%，为上下颌骨均整体旋转移动。结论    可以依据下颌骨体部、下颌骨升支是否对称，上颌骨是否随之发生明显的旋转把颜面部不对称畸形分成三类，便于颜面部不对称畸形的分类诊断、手术设计，有利于对此类疾病的进一步研究和学者间的交流。

关键词: 正颌手术, 数字化技术, 不对称畸形, 三维重建, 分类