动态载荷下不同骨质对天然牙-种植体联合修复应力分布的影响

目的 利用有限元方法探索下颌后牙区天然牙-种植体联合修复在不同骨质内的应力分布情况，以评定出适宜行联合修复所需的骨质类型。方法 采用三维有限元分析法，分别对骨质为Ⅰ、Ⅱ、Ⅲ、Ⅳ类颌骨类型中的天然牙-种植体联合修复体施加动态载荷，并对各界面所承受的Von Mises应力进行分析。结果 皮质骨所受最大Von Mises应力值从Ⅰ类骨到Ⅳ类骨逐渐增大，最大等效应力分别为89.229、91.860、125.840、158.420 MPa。松质骨所受最大Von Mises应力值从Ⅰ类骨到Ⅳ类骨均逐渐减小，最大等效应力分别为58.584、43.645、21.688、18.249 MPa。在同一类模型中，松质骨和皮质骨的最大Von Mises应力值均为舌颊向加载>颊舌向加载>垂直向加载。结论 骨质的类型对修复体周围骨的应力分布有重要的影响，Ⅰ、Ⅱ类骨较Ⅲ、Ⅳ类骨更适合行种植体-天然牙联合修复。

Evaluation of the stress distribution in tooth implant-supported fixed partial prostheses on different bone types under dynamic loads

Objective This study aims to evaluate the influence of different bone types on the stress distribution in tooth implant-supported fixed partial prostheses by using finite element (FE) analysis. Methods Four FE models of mandibular arch containing one implant splinted to the mandibular second premolar were built according to bone types Ⅰ, Ⅱ, Ⅲ, and Ⅳ. Dynamic loads of 250 N were applied to the buccal and lingual cusps of the prostheses in different directions to simulate the masticatory cycle. The maximum Von Mises stresses were calculated using the FE analysis software. Results The maximum Von Mises stresses of the cortical bones were 89.229, 91.860, 125.840, and 158.420 MPa, increasing from type Ⅰ to type Ⅳ, respectively. The maximum Von Mises stresses of the trabecular bone were 58.584, 43.645, 21.688, and 18.249 MPa, decreasing from type Ⅰ to type Ⅳ, respectively. During the process of dynamic loading, the maximum Von Mises stresses of the cortical and trabecular bones followed the order buccal to tongue loading>tongue to buccal loading>vertical loading. Conclusion The results showed that bone type significantly influenced the stress distribution in bones, and that for tooth implant-supported fixed partial prostheses, bone types Ⅰ and Ⅱ were a better choice than bone types Ⅲ and Ⅳ. More caution should be exercised when restoring missing teeth using tooth implant-supported fixed partial prostheses in softer bone regions.