上颌骨全切术后缺损定制化修复体的三维有限元应力分析

The individual reconstruction of maxillary operative defect analysed by three-dimensional finite element stress analysis

目的:建立定制化的单侧上颌骨缺损修复体的三维有限元模型,对其表面应力进行三维有限元分析,筛选获得良好的固位方式。方法:采用螺旋CT扫描、数字影像传输,应用Mimics、Geomagic Studio和Ansys软件,建立定制化的单侧上颌骨缺损修复体的有限元模型,对不同的固位方式下,修复体的表面应力进行分析。结果:获得了单侧上颌骨缺损修复体的三维有限元模型,不同的固位方式下修复体表面的最大应力集中区均位于对侧牙槽突区延伸板靠近缺损侧下方的钉孔处,应力值的大小在50.491-113.334Mpa。与鼻根区延伸板固位螺钉的有无及对侧牙槽突区固位螺钉的排布密切相关。结论:建立了单侧上颌骨缺损修复体的有限元模型,修复体的固位方式采用鼻根区1枚螺钉,对侧牙槽突区采用呈△排列的3枚螺钉(近缺损侧1枚、远缺损侧2枚)固位较好。

Objective：To build a individual three - dimensional finite element model of the common unilateral maxillary defect, and the three -dimensional finite element stress analysis was carried out for the facial stress, then gain an ideal retention mode. Methods： The individual three - dimensional finite element model of the common uni- lateral maxillary defect and maxillofacial prosthesis were constructed by means of spiral CT scanning, digital image transfer, Mimics, Geomagic Studio and Ansys software. The facial stress of the prosthesis was analysed for the differrent retention mode. Results ： The individual three - dimensional finite element model of the common unilateral maxillary defect and maxillofacial prosthesis were established. For the different retention mode, all the biggest stress of the prosthesis was on the opposite side alveolar process district extend plate near to the inferior countersink of defect side, the magnitude of the stress value was 50.491 - 113. 334 Mpa. The stress was closely correlated with the availability of retaining screw of the nasal root district extend plate and the assignment of retaining screw of opposite side alveolar process district. Conclusion：The individual three - dimensional finite element model of the common unilateral maxillary defect and maxillofacial prosthesis was constructed. To employ one bolt in the nasal root district and three bolts （disposed as triangle） in the opposite side alveolar process district（one near to defect side, others are far to defect side） ,this kind of retention mode of prosthetic replacement is better.