Micro-CT技术结合逆向工程软件建立上颌第一前磨牙的三维有限元模型

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。

Micro-CT technology combined with reverse-engineering software in establishing a three-dimensional finite element model of maxillary first premolar

To establish the three-dimensional finite element model of maxillary first premolar by using simple and effective method,which providing mathematic model for biomechanic research.Methods: Micro-CT was used to scan the extracted, intact maxillary first premolar .Collecting the point data images of enamel, dentin, and pulp by Mimics 10.0 software, which were imported into Imageware12.0 software to deal with point cloud data and inverse algorithm of curve. After surface fitting, the tooth solid model was accomplished by Ansys 11.0 software. Then, enamel, dentin, and pulp were integrated through Boolean operation in Ansys 11.0,while the solid model of periodontium and alveolar bone were constructed, and the 3D meshes were created respectively. At the same time,the model was undered loading.Result: This study established a fine three-dimensional finite element model of maxillary first premolar including pulp, periodontium and alveolar bone. After 3D meshing, the enamel had 26, 685 tetrahedral elements, the dentin had 114,082 tetrahedral elements, the pulp had 11,843 tetrahedral elements, the periodontium had 22,004 tetrahedral elements,the alveolar bone had 66,767 tetrahedral elements. In total, the model had 241,381 10-node-tetrahedral elements. The accuracy of the model was very high. It is real reflected the figure of the tooth and the curvilinear shape of enamelo-cemental junction. Conclusions: By using and combining the Micro-CT technology and reverse-engineering software, this study established a three-dimensional finite element model of maxillary first premolar. This model has favourable geometric and mechanical comparability, which imitating the stress distribution of loading.