下颌后缩患者的下颌形态测量研究

目的:将几何形态测量法引入正畸学,对下颌后缩患者的下颌形态进行全面的定量研究。方法:对30例下颌后缩患者的头颅定侧位片进行对照研究,分别采用常规头影测量分析、最小平方和重叠法、欧氏距离矩阵分析法、薄板分析法来评价下颌形态。结果:下颌后缩组的髁突宽度、长度以及升支高度明显较小,说明髁突和升支发育受到抑制。牙槽突在垂直向和水平向上都有明显增加,说明此处有代偿性生长。结论:几何形态测量法可以定量的对形变加以描述,输出结果也更为直观。并且排除了下颌旋转及位置变化对结果所产生的影响,使结果更为可信。

Morphometric Study of the Mandible in subjects with Mandibular Retrusion

Objective: The purpose of this study was to quantitatively evaluate the mandibular morphology of patients with mandibular retrusion.Methods: Lateral cephalographs of 30 adolescents with mandibular retrusion were compared to those of 36 counterparts with normal occlusion.All cephalographs were scanned and 14 homologous mandibular landmarks were digitized.The resulting configurations were analyzed using cephalometric analysis,Procrustes superimposition,Euclidean distance matrix analysis,and Thin-plate spline analysis.Results: In this study,the condylar process was found to shorten in the experiment group in comparison to the control group. Ramus height and condylar width reduced in the mandibular retrusion group,which was a result of condylar growth inhibition during adolescence.Conversely,the length and the vertical height in the symphysis were significantly greater in the experiment group.Conclusion: The geometric morphometry,as a new practical method of dealing with cephalometric measurements,enabled us to quantitatively measure size and shape separately,to provide visual comparisons in a global view,and to exclude translation or rotation.The method offered a great advantage over traditional cephalometrics.