不同桩核材料对牙根应力状况的影响

Three-dimensional finite element stress analysis of dental root restored with different post material

目的探讨不同桩核材料对牙根应力状况的影响,为临床桩核材料的选择提供实验依据。方法建立下颌第二前磨牙桩核冠的三维有限元模型,据此分析铸造镍铬合金、铸造金合金、铸造钛合金及氧化锆、聚乙烯纤雏树脂、玻璃纤维树脂、碳纤维树脂等7种桩核材料修复前后的牙本质应力分布状况。结果桩核冠修复前,牙根应力峰值出现在牙根颈部的外表面；修复后,随着核桩弹性模量的增高,根颈部外表面的应力峰值降低,而桩及其与牙本质交界面的应力值显著上升。结论为防止桩-牙本质交界面应力显著上升致根折,临床上对于细弱壁薄的牙根,宜选用接近牙本质的低弹性模量的桩核材料。

Objective To observe the stress distribution in the dentin with post - core restored with different materials and to provide a theoretical guidance for clinical application. Methods Three- dimensional finite element model of mandible second premolar restored with post - core and all - ceramic crown was built. By comparing seven types of post materials（cast Ni- Cr alloy,cast titanium alloy, cast gold alloy , zirconium- oxide, polythene fiber reinforced composite, glass fiber reinforced composite, carbon fiber reinforced composite under static loading）, the stress distribution was analyzed. Results Before restoration, the stress was recorder mainly in the superior third of the root surface. After restoration, especially with high Yang＇s modulus materials, the stress increased markedly in the interface of post and dentin. Conclusion For fragile roots, low Yang＇s modulus materials may be suitable for post restoration in order to decrease the danger of root fracture.