桩核黏接剂厚度对上中切牙应力影响的三维有限元分析

Finite element analysis of stress distribution in post and core restored maxillary central incisor with different thickness of cement

目的：应用三维有限元法分析桩核黏接剂层厚度对上中切牙应力的影响。方法：建立上颌中切牙桩核冠修复体三维有限元模型，与牙长轴呈45°舌侧静态加载，力值大小为118N，分析当黏接剂层厚度分别为0．03mm、0．05mm、0．07mm、0．10mm时牙本质的最大主应力、最小主应力和Von Mises应力分布规律和峰值。结果：不同厚度组模型牙本质内3种应力分布规律及峰值基本类似。各组最大主应力的高应力区均位于舌侧根颈部，最小主应力的高应力区均位于根尖部，Von Mises应力的高应力区在根尖部以及根上1／3唇、舌面。结论：桩核黏接剂厚度在0．03～0．10mm范围内时对牙本质的应力状况影响较小。

Aim：To study the stress statement of the post and core restored maxillary central incisor with different thickness of the cement. Methods：Four three dimension finite element（3D-FEM） models of a post and core restored maxillary central incisor were built. Each of the models received a 45° oblique lingual load at a constant intensity of 118 N. The four levels of cement thickness were 0.03 mm, 0.05 mm, 0.07 mm, and 0.10 mm. The stress of the dentin was investigated with different thickness of the cement. Results ： There was no significant difference in the three types of stress distribution and the peak stress with different thickness. The maximum stress was recorder mainly on the lingual aspects of root cervical region. The minimum stress was found mainly around the root apical. The significant concentration of Von Mises stress was occurred on both the lingual and facial aspects of the superior thirds of the root. Conclusion ： When the thickness of cement varies from 0.03 mm to 0.10 mm, it has less effects on the stress distribution.