假体重建板固位设计的生物力学评价

Biomechanical evaluation of reconstruction plate for fixation of mandibular prosthesis

目的:对传统重建板固位方式进行生物力学评价,探索下颌骨假体的合理固位方式。方法:选择1例华东地区正常成年男性,建立基于CT图像数据文件的下颌骨三维有限元模型,计算机模拟半侧下颌骨缺损,设计重建板固位方式的下颌骨假体修复,分析4种工况下固位结构的应力分布特征。采用SAS6.12软件进行t检验及方差分析。结果:4种工况条件下,重建板固位结构应力基本呈等强度分布(F=2.87,P>0.05);4枚固位钛钉周围骨组织所承受的最大应力值无统计学差异(F=0.8,P>0.05),但显著低于正常松质骨的最佳应力值(t=-44.9773,P=0.0001)。结论:重建板固位方式应力分布基本合理,但不利于周围骨组织的改建。

PURPOSE： Biomechanical analysis was performed on reconstruction plate to explore the reasonable fixation method of mandibular prosthesis. METHODS： Three dimensional finite element model of the mandible was established based on CT images of a normal occlusion adult from east China released as DICOM file by ANSYS software. The mandibular prosthesis with fixation of reconstruction plate was designed by applying CAD software for repair of hemimandibular defect in the computer. The stress distribution on the fixation structures under the four loading conditions was investigated. The data were analysed statistically with SAS6.12 software package. Student＇s t test was used for comparing the differences. RESULTS： Reconstruction plate and screws basically presented with equal stress distribution under four loading conditions （F=2.87,P=0.0704）. The stress distribution on bony tissue surrounding screws had also no significant difference （F=0.8,P=0.5943）, but significantly less than optimal stress of normal cancellous bone （t=-44.9773, P=0.0001）. CONCLUSION： Reconstruction plate for fixation of mandibular prosthesis basically underwent reasonable stress distribution, but had no benefit for remodeling of adjacent bone. Supported by Shanghai Leading Academic Discipline Project （Grant No.Y0203） and Research Fund of Science and Technology Committee of Shanghai Municipality （Grant No.054119535）