Establishment of Systems based on Biomechanical Analysis for Cleft Palate Treatment

腭裂患者的牙颌面骨骼和咀嚼系统存在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困难性。为了进一步了解治疗的有效性和建立相当的程序，我们需要对我们的治疗进行生物力学分析。此外，评估上颌骨的骨矿化具有重要的临床意义。牙齿移动和/或牙弓扩张取决于牙槽骨内的骨矿化水平。在本研究中，我们提出了一些方法，结合形态测量，功能评估和力学分析。开发了新的计算软件程序。采用CT扫描和铸型测量获得的个体化数字数据进行分析。根据CT数据构建患者特定有限元模型。机械性能（即，杨氏模量）使用X射线衰减值（即，GT数），通过坐标变换法调整结构性质。应用该系统测定了扩腭和颏帽治疗时的骨密度分布和生物力学行为。结果表明，正常人的高切应力区呈双侧对称分布。但在腭裂患者中，骨密度分布和骨膨胀位移随骨密度值的变化而变化，这些计算机辅助程序可用于获得个体的临床有用信息。

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.