不同设计桩核的后牙残根核桩冠修复体的三维有限元应力分析

目的采用三维有限元法比较不同长度和数目桩核、不同材料桩核对后牙残根桩核冠修复体牙本质应力大小及其分布的影响，探讨后牙残根桩核冠修复时合理的桩核设计及选材。方法采用CT扫描、Mimics软件及Abaqus软件建立上颌第一磨牙桩核冠的三维有限元模型。根据桩长度和数目的不同、桩核材料的不同，将上颌第一磨牙桩核冠的三维有限元模型分为相应的实验组。在模型咬合面上选取3个载荷点，分别施加80 N的载荷，计算各实验组中牙本质上的Von mises应力、最大主应力、剪切应力的应力峰值及分布方式。结果在桩长度和数目不同时，随着桩长度和数目的增加，牙本质上各项应力峰值呈现不规律变化。在不同桩核材料时，随着桩核材料弹性模量的增加，牙本质上的Von mises应力、最大主应力、剪切应力峰值均减小。结论在本实验研究条件下，不同桩长度和数目、不同桩核材料对后牙残根桩核冠修复体牙本质上的应力峰值和应力分布均有影响。

The three-dimension finite element analysis of stress in posterior residual root restored with different designed post-core crown

Objective To analyze the stress magnitude and distribution of remaining dentin in posterior residual root restored with post-core crown by three-dimension finite element methods. The variables were number, length and material of post. Methods The models of residual root of maxillary first molar restored with post-core crown were created by CT scanning, Mimics software and Abaqus software. Different number, length and material of posts were used in the modeling. The post was cemented with zinc-phosphate cement. A load of 240 N was applied to the occlusal surface in vertical direction and tensile, shear, and Von mises stresses were calculated. Results The maximum stresses on remaining dentin changed irregularly as the number and length of post. The maximum stresses on remaining dentin decreased slightly as elastic modulus of the material of post increase. Conclusion The number, length, material of post have influence on magnitude and distribution of stress.