基于有限元法的引导骨再生用个性化钛网受力分析

Force analysis of personalized titanium mesh for guided bone regeneration based on finite element method

目的基于有限元分析的方法,观察不同厚度、不同孔隙率、不同杆径单胞结构填充的钛网在垂直外力作用时的应力和位移分布,为颌骨缺损时引导骨再生的个性化钛网设计提供生物力学依据。方法分别以31-32缺失和33-37缺失的两位患者的下颌骨作为小尺寸钛网(S型)和大尺寸钛网(L型)的研究载体,分别重建颌骨模型,设计不同厚度、孔隙率及杆径的钛网,构建三维有限元模型,通过有限元方法分析钛网承力情况下的应力和位移分布。结果随着钛网厚度的增加,钛网的应力和位移呈现下降趋势;随着钛网孔隙率的增加,钛网的应力和位移呈现上升趋势;随着钛网杆径的增加,钛网的应力和位移呈现不同趋势,其中S型钛网呈现下降趋势,而L型钛网无明显变化。结论钛网厚度在0.4 mm及以上时,所有钛网的应力值均在安全等效应力范围内,考虑到钛网过厚会对黏膜产生刺激,0.4 mm厚度钛网更适合临床需要;S型的孔隙率在55%及以下,L型孔隙率在55%~68%时,应力值在安全等效应力范围内,提高钛网孔隙率可以提供更充足的血液通道给黏膜,降低黏膜缺血萎缩与开裂的风险,L型钛网应尽量选择68%孔隙率,S型钛网选择55%孔隙率;S型钛网杆径在0.7 mm及以上,L型钛网杆径在0.5 mm及以上时,S型和L型钛网均可满足强度要求,综合孔隙率等因素,考虑杆径越大对黏膜刺激增大,因此0.7 mm杆径的钛网更适合临床需要。

Objective Based on finite element analysis,the stress and displacement distributions of the titanium mesh were analyzed under different thicknesses,different porosities and different rod diameter of the fillings of the convention unit cell structure in response to vertical external forces.The results of the analysis can provide a biomechanical basis for the design of personalized titanium mesh when used to guide bone regeneration in the treatment of jawbone defects.Methods The mandible of a patient with 31-32 defects was used as a study carrier for small-sized titanium mesh(S-type),and the mandible of a patient with 33-37 defects was used for large-sized titanium mesh(L-type).A 3D model reconstruction of the jaws was performed for their CBCT images,respectively.Based on this,titanium mesh with different thicknesses,porosities,and rod diameters was designed,and 3D finite element models were established.The stress and displacement distribution of the titanium mesh under stress conditions was analyzed by FEM analysis.Results With an increase in titanium mesh thickness,the stresses and displacements of titanium mesh show a decreasing trend;with an increase in the porosity of titanium mesh,the stresses and displacement of titanium mesh show an increasing trend;with an increase in the diameter of the titanium mesh rod,the stress and displacement of S-type titanium mesh showed a decreasing trend,while the stress and displacement of L-type titanium mesh showed no obvious trend.Conclusion The stress values of all titanium meshes are within the safe equivalent stress range with sufficient strength for thicknesses of 0.4 mm and above,considering that too thick titanium mesh will stimulate the mucosa,0.4mm thickness titanium mesh is more suitable for clinical needs;stress values were within the safe equivalent force range for S-type with 55%porosity and below,and L-type with 55%~68%porosity,with sufficient strength,increasing the porosity of titanium mesh can provide more adequate blood channels to the mucosa,reducing the risk of mucosal ischemia atrophy and cracking,L-type titanium mesh should try to choose 68%porosity,S-type titanium mesh should choose 55%porosity;S-type titanium mesh rod diameter at 0.7 mm and above,L-type titanium mesh rod diameter at 0.5 mm and above,can meet the strength requirements,comprehensive porosity and other comprehensive factors,considering that the larger the rod diameter,the mucosal stimulation increases,so the 0.7 mm rod diameter titanium mesh is more suitable for clinical needs.