下颌支矢状骨劈开术数字模型的建立及不同固定方式的稳定性分析

The establishment of digital model about sagittal split ramus osteotomy and stability analysis of 3 different fixation methods

目的:建立下颌支矢状骨劈开术数字模型,探讨3种不同固定方式的应力及位移改变。方法:CT扫描数据导入三维重建软件Mimics以及Geomagic中,建立下颌骨三维实体模型,并进行矢状劈开、坚固内固定,ANSYS进行网格划分,建立三维有限元模型。边界约束后,进行双侧下颌第一磨牙咬合力(132 N)加载。结果:建立了双侧下颌支矢状骨劈开术3种不同固定方式三维有限元模型,获得术前下颌骨及矢状骨劈开后咬合力加载的应力及位移生物力学特点。结论:下颌支矢状骨劈开术倒L形固定应力分布最均匀,劈开处位移最小,与其他2种方式相比,其固定稳定性最佳。

PURPOSE： To establish the digital model about sagittal split ramus osteotomy and discuss the stress and displacement of 3 different fixation methods. METHODS： Three-dimensional reconstruction software Mimics and Geomagic were used to establish the three-dimensional entity model of mandible, and simulated sagittal split ramus osteotomy and fixation. Three-dimensional finite element model was established by mesh generation through ANSYS. After boundary constraint the occlusal load of 132N on the bilateral lower first molars was applied. RESULTS： Threedimensional finite element models of sagittal split ramus osteotomy and 3 different fixation methods were established, and the biomechanical character of stress and displacement after occlusal load preoperatively and after splitting mandibles were found. CONCLUSIONS： As the stress distribution tends to uniformity and the displacement at split area is the least one, the fixation by bicortical screws in inverted-L position after sagittal spht ramus osteotomy is the stablest of the 3 fixation methods. Supported by Natural Science Foundation of Guangdong Province （S2011010003872） and Science and Technology Projects of Guangzhou City （7421165457455）.