不同材料桩核冠系统修复上中切牙后的三维有限元分析

目的:研究铸造玻璃陶瓷、铸造金属烤瓷桩核冠系统修复上中切牙后应力分布的规律，为临床工作提供理论参考依据。方法:用三维有限元法对不同材质的桩核冠在相同载荷下各组成部分的应力分布差异以及变形进行生物力学分析。结果:铸造玻璃陶瓷桩核冠与铸造金属烤瓷桩核冠在相同载荷作用下。前者对上中切牙牙本质产生的应力及整体变形稍大，后者的桩核部分应力稍大，两者的牙骨质、牙周膜和牙槽骨应力相差很小；外冠的材质对牙体应力分布的影响非常小，而桩核的材质对牙体应力的分布有影响；外冠是否存在对计算结果影响很大。结论:铸造玻璃陶瓷桩核冠与铸造金属烤瓷桩核冠在相同载荷作用下．对上中切牙的影响非常接近；尽量采用弹性模量较大的材料来制作桩核；用三维有限元法对桩核冠进行的应力分析时不能省略外冠。

Three dimensional finite element stress analysis on the post-crown restored upper mesio-incisal teeth with different materials

Objective To study the stress distribution discipline of the upper mesio-incisal teeth restored by two kinds of materials, casting glass-ceramics and casting metal post-core-crown system to theoretical reference for clinic work. Methods The stress distribution of the different post-core-crown was studied and analyzed by three dimensional finite element under the same loads. Results Under the same composition of forces, the stress for dentin and whole distortion of the casting glass-ceramics was slightly bigger, and the stress for post-core of the later was a little bigger. As to cementum, periodontal membrane and alveolar bone, there was no obvious difference between these two kinds of materials. The crown material's influence on the stress distribution was very little, but the material of post-core was more influential. It was very important for calculation whether or not the crown existed. Conclusions Under the same loads, the influences on the mesio-incisal teeth were approximately similar between casting glass-ceramics and casting metal post core-crown system. We propose using the material with big elastic modulus for making post-core. It is necessary to put the crown on during analyzing the post-core-crown system by three dimensional finite element.