基于三维有限元技术构建的小型猪下颌骨模型及其生物力学特点

On the basis of three-dimensional finite element technique to construct a mandible model of the miniature pig and study its biomechanics.

目的构建小型猪下颌骨有限元模型,探索在加载负荷时下颌骨的应变及应力变化特点,为分析后续研发的下颌骨外固定架的生物力学性能奠定基础。方法选择1只体重为20kg的健康巴马小型猪行头颅CT扫描,将扫描的DICOM数据导入Mimics 17.0软件行三维图像重建,生成STL格式的曲面文件,再将STL文件导入逆向工程软件GeomagicStudio中进行数据预处理,生成IGES格式的通用曲面几何文件,将IGES格式的文件导入ICEM软件中进行网格划分,输出UNS网格文件,最后将其导入到Workbench软件中,设置材料属性及定义边界条件,完成数据后处理。应用该模型模拟咬合力,依次在左侧下颌第一磨牙上加载9.8～392N垂直向下的载荷,分析下颌骨的应变及应力变化,测试模型的稳定性。结果应用医学数字图像软件及三维有限元分析软件成功建立了小型猪下颌骨有限元模型。行载荷分析时模型运行稳定,生成数据合理,模型中的下颌骨未出现连续性中断。结论建立的小型猪下颌骨三维有限元模型可模拟下颌骨的应变及应力变化,为小型猪下颌骨外固定架的设计提供仿真力学分析基础。

Objective The finite element model of the mandible of the miniature pig was constructed to explore the strain and stress changes of the mandible during loading, which laid the foundation for the analysis of the biomechanical properties of the subsequently developed mandibular external fixation holder. Methods We randomly selected a healthy Bama miniature pig, weighing 20kg, and made a CT scan to its head for obtaining the DICOM data. The DICOM data were imported into the software Mimics17.0 for 3D image reconstruction, and output the STL format. Then we imported the STL format into Geomagic Studio software to make data preprocessing, and got general curved surface file in IGES format. Then we imported the IGES format into ICEM software to carry on the grid, output the UNS grid file, then we imported it into the Workbench software for setting material attributes and definition of boundary conditions, and data post-processing. Applying this model, we simulated the occlusal force and loaded 9.8-392 N vertically downward on the left mandibular first molar, then calculating the strain and stress changes of the mandible and testing the stability of the model. Results Using medical digital image and three-dimensional finite element analysis software, we had successfully established an ideal mandibular model of miniature pig. When loading on the mandible, the results showed that there was no continuous interruption and the data generated were reasonable. Conclusions The three-dimensional finite element model of the mandible of the miniature pig can effectively simulate the strain and stress changes of the mandible, and provide a simulation mechanical analysis for the reasonable design of the external fixationholder.