This study was aimed at determining the three-dimensional differences in the mandible morphology between skeletal class I and II patients, at exploring the pathogenic mechanisms and morphological characteristics of skeletal class II, and at providing clinical references. The subjects were assigned to two groups according to the size of ANB angle: skeletal class I () and skeletal class II (). After cone-beam computed tomography (CBCT) scanning, 31 landmarks and 25 measurement items were determined by In Vivo Dental 5.1 software (Anatomage, CA) for statistical analysis. The results were as follows: Co-Go, Go-Me, and CdM-CdD in skeletal class II cases were smaller than those in skeletal class I, and GoR-Me-GoL, GoR-Me-CoL, and, Ig-Men were larger than those in skeletal class I cases. In conclusion, there were significant differences in the three-dimensional morphology of the mandible between skeletal class I and class II patients. The vertical growth of the ramus, the horizontal growth of the mandibular body, and the condyle in skeletal class II patients were smaller than those in skeletal class I cases. In skeletal class II, the growth of the anterior part of the mandible in the vertical direction was larger than that in skeletal class I, and the shape of the mandible was more extended.

中文翻译：

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CBCT定点测量法分析Ⅰ类与Ⅱ类骨骼下颌骨三维形态差异

本研究旨在确定I类和II类骨骼患者下颌骨形态的三维差异，探讨骨骼II类患者的发病机制和形态特征，为临床提供参考。根据ANB角的大小将受试者分为两组：骨骼I类（)和骨骼类 II (）。在锥形束计算机断层扫描（CBCT）扫描后，通过 In Vivo Dental 5.1 软件（Anatomage，CA）确定 31 个标志和 25 个测量项目进行统计分析。结果如下：骨骼II类病例的Co-Go、Go-Me和CdM-CdD小于骨骼I类病例，GoR-Me-GoL、GoR-Me-CoL和Ig-Men大于骨骼 I 类病例。综上所述，I类和II类骨骼患者下颌骨三维形态存在显着差异。骨骼Ⅱ类患者的支的垂直生长、下颌体的水平生长和髁突均小于骨骼Ⅰ类患者。在骨骼类 II 中，