Establishment of Systems based on Biomechanical Analysis for Cleft Palate Treatment

在腭裂患者中，众所周知，他们的牙颌面部骨骼和咀嚼系统表现出严重的畸形和功能障碍。这些形态和功能特征导致了正畸治疗的复杂性和难度。为了进一步了解治疗效果和建立相当的程序，我们需要对我们的治疗进行生物力学分析。此外，评估上颌骨骨矿化具有重要的临床意义。正畸牙齿的移动和/或牙弓的扩张取决于牙槽骨内骨矿化的水平。在这项研究中，我们提出了一些结合形态测量、功能评价和力学分析的方法。开发了新的计算软件程序。从CT扫描和铸造模型测量中获得的个人数字数据用于分析。根据CT数据建立患者特定的有限元模型。采用x射线衰减值（即GT数）评价力学性能（即杨氏模量），采用坐标变换法调整结构性能。在腭扩张和颏帽治疗下测定骨密度分布和生物力学行为。结果表明：正常受试者具有双侧对称的高剪应力区域分布。而腭裂患者骨密度分布的改变和扩张引起的移位取决于骨密度值。这些计算机辅助程序可用于获得个体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.