Abstract:

Objective: To examine the effects of orthognathic surgery on the condylar morphology in patients with skeletal class Ⅲ malocclusion and mandibular deviation, as well as the variations in condylar morphology and alterations in individuals with varying degrees of deviation. Methods: According to the value of menton deviation (MD), 20 patients with skeletal class Ⅲ malocclusion and mandibular deviation were selected, and then divided into group A (mild deviation group: 4 mm≤MD<10 mm) and group B (severe deviation group: MD≥10 mm), 10 cases in each group. Condyles were three-dimensionally reconstructed in Proplan CMF using the craniofacial spiral CT data from the T1 (before surgery) and T2 (six months after surgery) periods. Condylar morphological index (MI) was derived after reading the condylar volume and surface area. Results: Condyles in group A had a decrease in volume and surface area in T2 (P<0.05) on both the deviated side (DS) and the non-deviated side (NDS). For condylar volume, surface area, and MI during the T1 and T2 periods in each group: The NDS was larger than the DS, and the bilateral difference was statistically significant as group A is smaller than group B; the values of each index in group A were higher than those in group B, and there was a statistical difference in the DS (P<0.05). There was a statistical difference in the magnitude of changes in volume and surface area between the two groups on the DS (P<0.05), and the degree of condylar change between T2 and T1 is different. Conclusion: Condylar volume and surface area were reduced after orthognathic surgery, and statistically significant differences in condylar volume and surface area reduction were more pronounced in the mildly deviated group at 6 months postoperatively on the DS. Condylar volume, surface area, and MI were less than those on the NDS, and the DS indexes were higher in individuals with mild deviation than in individuals with severe deviation. The morphological changes of condyles after surgery were related to the degree of deviation.

Key words: skeletal class Ⅲ malocclusion, mandibular deviation, orthognathic surgery, condylar morphology, three-dimensional reconstruction

摘要：

目的：探讨正颌手术对骨性Ⅲ类错𬌗畸形下颌偏斜患者髁突形态的影响，以及不同偏斜程度患者髁突形态和变化的差异。方法：选取20例骨性Ⅲ类错𬌗畸形伴下颌偏斜患者，根据颏下点偏离值（menton deviation，MD）分为A组（轻度偏斜组：4 mm≤MD<10 mm）和B组(重度偏斜组：MD≥10 mm），每组各10例。将患者术前（T1）、术后6个月(T2)颅面部CT数据导入Proplan CMF软件，三维重建获得髁突模型，读取髁突体积、表面积，计算髁突形态学指数（morphometric index，MI）。结果：T2时A组偏斜侧(the deviated side，DS)与非偏斜侧(the non-deviated side，NDS)髁突体积与表面积均减小（P<0.05）；2组T1、T2时NDS髁突体积、表面积、MI均大于DS，双侧差异的统计学意义，B组更显著；A组各指标数值大于B组，2组DS各指标的差异有统计学意义(P<0.05）；T2较T1时髁突变化幅度不同，2组DS体积、表面积变化幅度差异有统计学意义（P<0.05）。结论：正颌手术会导致术后髁突体积与表面积减小，且术后6个月时轻度偏斜组髁突体积与表面积减小的统计学差异更加显著。患者DS髁突体积、表面积及MI小于NDS，轻度偏斜者DS髁突体积、表面积及MI大于重度偏斜者，术后髁突形态变化与偏斜程度相关。

关键词: 骨性Ⅲ类错牙合畸形, 下颌偏斜, 正颌手术, 髁突形态, 三维重建

CLC Number: 

• R782