Abstract: Objective: To investigate classification and characteristics of skeletal mandibular prognathism. Methods: Cephalometric tracing and measurement were performed on 51 individuals diagnosed with skeletal mandibular prognathism. 25 measurements were adjusted with age and gender, and processed by principle component analysis. Components with variance contribution more than 5% were used in the following cluster analysis. Morphological characteristics of each cluster were described. Results: After principle component analysis, 5 components were extracted, which explained a cumulative variance of 76.30%. 51 cases were classified into 3 groups: Cluster Ⅰ represented a sagitttal type of mandibular overdevelopment, while Cluster Ⅲ was a vertical type. Cluster Ⅱ exhibited a relatively mild mandibular deformity and obvious maxillary deficiency. All of the three type individuals showed hypodevelopment of maxilla. Conclusion: Morphology of skeletal mandibular prognathism manifested a heterogeneous pattern. Cephalometric classification of such patients may assist in diagnosis and treatment design of combined orthodontic and orthognathic treatment in clinical practice.

Key words: skeletal mandibular prognathism, combined orthodontic and orthognathic treatment, cephalometric tracing, cluster analysis

摘要： 目的：研究骨性下颌前突患者骨骼和畸形分型和不同类型患者的特征。方法：对51例骨性下颌前突患者进行头影测量分析，统计25项测量指标经年龄、性别校正后进行主成分分析，并使用核模聚类法进行聚类分析，描述各型患者骨形态特点。结果：25项测量数据经主成分分析提取前5个主成分，累计方差解释度为76.30%。51例骨性下颌前突患者可分为3个类型：第Ⅰ型表现为矢状型下颌发育过度，第Ⅲ型主要反映垂直型下颌发育过度，第Ⅱ型下颌发育过度严重程度较Ⅰ型和Ⅲ型轻微,上颌骨发育不足明显；各型患者均存在上颌发育不足。结论：骨性下颌前突患者骨骼形态具有异质性，对该类患者亚型的分类有助于临床正畸-正颌联合治疗的诊断和治疗设计。

关键词: 骨性下颌前突, 正畸-正颌联合治疗, 头影测量, 聚类分析

CLC Number: 

• R856.78