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目的利用简便有效的方法建立离体上颌第一前磨牙三维有限元模型,为生物力学研究提供数学模型基础。方法使用Micro-CT对离体、完整的左侧上颌第一前磨牙进行牙体扫描,将获得的CT影像转化格式,通过Mimics10.0软件采集釉质、本质及髓腔的点数据,导入Imageware 12.0软件中进行点云处理和曲线反求,通过Ansys 11.0软件完成曲面拟合形成牙体组织的三维实体模型并进行布尔运算,整合釉质、牙本质及髓腔系统;建立牙周膜以及牙槽骨的实体模型,分别进行网格划分,同时对模型进行力学加载。结果建立了包含髓腔、牙周膜、牙槽骨的上颌第一前磨牙的精细三维有限元模型,网格划分后的牙体三维有限元模型:釉质具有26 685个单元,牙本质具有114 082个单元,牙髓腔具有11 843个单元,牙周膜具有22 004个单元,牙槽骨具有66 767个单元,共有241 381个10节点四面体单元。模型具有非常高的精确度,真实反映了釉牙骨质界的形态。从应力分布来看釉质上应力主要集中在面中央窝和釉质与本质交界的边缘;同样牙本质的应力集中部分也在釉牙本质界处。结论通过Micro-CT技术与逆向工程软件相结合的方法建立了左侧上颌第一前磨牙的三维有限元模型,该模型具有良好的几何相似性和力学相似性。
Objective To establish a three-dimensional finite element model of anterior maxillary first premolars by using a simple and effective method to provide a mathematical model foundation for biomechanical research. Methods The left and right maxillary first premolar teeth were scanned by Micro-CT. The acquired CT images were converted to the enamel, essence and marrow cavity by Mimics 10.0 software and imported into Imageware 12.0 Software for point cloud processing and reverse curve, Ansys 11.0 software to complete the surface fitting to form three-dimensional solid model of tooth tissue and the Boolean operation, the integration of enamel, dentin and pulp cavity system; the establishment of periodontal ligament and alveolar bone Of the solid model, respectively, meshing, while the model for mechanical loading. Results Fine three-dimensional finite element model of the maxillary first premolar containing the medullary cavity, periodontal ligament and alveolar bone was established. The three-dimensional finite element model of the tooth body after meshing: the enamel has 26 685 units and the dentin has 114 082 units, with 11 843 units in the pulp chamber, 22 004 units in the periodontal ligament, 66 767 units in the alveolar bone, and 241 381 10-node tetrahedron units in total. Model has a very high accuracy, a true reflection of the glaze cementum morphology. From the stress distribution point of view, the stress on the enamel is mainly concentrated on the edge of the central fossa and the boundary between the enamel and the essence of the enamel; the stress concentration of the same dentin is also located in the enamel dentin boundary. Conclusion The three-dimensional finite element model of left maxillary first premolar is established by the combination of Micro-CT and reverse engineering software. The model has good geometric similarity and mechanical similarity.