Establishment of Systems based on Biomechanical Analysis for Cleft Palate Treatment

在腭裂患者中，众所周知，他们的牙颌面骨骼和咀嚼系统显示出严重的畸形和功能障碍。这些形态和功能特点造成了正畸治疗的复杂性和难度。为了进一步了解治疗的有效性和建立相当大的程序，我们需要对我们的治疗进行生物力学分析。此外，评价上颌骨的骨矿化具有重要的临床意义。正畸移动牙齿和/或牙弓扩张取决于牙槽骨内的骨矿化水平。在本研究中，我们提出了一些将形态测量、功能评价和力学分析相结合的方法。开发了新的计算软件程序。采用CT扫描和管型测量所获得的个体数字化数据进行分析。根据CT数据建立患者特有的有限元模型。用X射线衰减值(即GT数)评价材料的力学性能(杨氏模量)，用坐标变换法调整材料的结构性能。通过我们的新系统，我们确定了在扩弓和下颌盖治疗下的骨密度分布和生物力学行为。结果表明，正常受试者双侧高切应力区域呈对称性分布。然而，在腭裂患者中，发现骨密度分布和扩张引起的移位依赖于密度值。这些计算机辅助程序可以用来得出个别受试者的临床有用信息。

In cleft palate patients, it is well recognized that their dento-maxillo facial skeletons and masticatory systems demonstrate severe deformity and malfunctions. Complexity and difficulty of orthodontic treatment was caused on these morphological and functional characteristics. For further understanding of treatment effectiveness and establishment of considerable procedure, we need a biomechanical analysis of our treatment. Iii addition, evaluating bone mineralization of the maxilla has important clinical implications. Moving teeth orthodontically and/or expansion of dental arch depended upon the level of bone mineralization within the alveolar bone. In this study, we proposed some methods which integrate morphological measurement, functional evaluation and mechanical analysis. New computational software programs were developed. Individual digital data derived from CT scanning and measurement of cast model were used for analysis. Patient specific Finite Element Model was constructed from CT data. Mechanical properties (i.e., Young's modulus) were evaluated using x-ray attenuation value (i.e., GT number), structural properties were adjusted by coordinate transformation method. Bone density distribution and biomechanical behavior under palatal expansion and chin cap therapy were determined by our new system. The results showed that the normal subjects had a bilaterally symmetrical distribution of regions with high shear stress. However in cleft palate patient, altered bone density distribution and displacement by expansion depend on density value were found. These computer-assisted programs can be used to derive clinically useful information in individual subjects.