Patra A K, DePaolo J M, D'Souza K S, DeTolla D, Meenaghan M A
Department of Mechanical and Aerospace Engineering, School of Engineering and Applied Sciences, State University of New York at Buffalo, USA.
Implant Dent. 1998;7(4):355-68. doi: 10.1097/00008505-199807040-00015.
This article describes the simulation of the mechanical behavior of two types of endosseous-threaded dental implants and the development of design guidelines for such implants. Two- and three-dimensional representations, static and dynamic cyclic loads, different material models, axial loads, and loads directed at the occlusal angle are all used. A novel model of trabecular bone is used to incorporate fatigue effects. Directional material behavior, progressive bone loss, and partial osseointegration are also modeled. Bone support using muscle attachment is modeled using spring constraints as opposed to fixed constraints used in previous studies. The tapered thread design from Brånemark Inc. exhibited higher stress levels in bone than those observed in the parallel profile thread from BUD Medical Devices, Inc. The BUD implant distributes stresses more evenly. Studies examining 25%, 75%, and 100% osseointegration showed cortical bone carried most of the load with resulting overload leading to crestal bone loss. Plots of stress showed that with increasing crestal bone loss, the majority of the load was transferred directly to the weaker trabecular bone tissue. Finally, it was shown that with proper implant redesign, loads can be transferred more evenly to the implant. This also improves fatigue life of the bone.
本文描述了两种骨内螺纹牙种植体力学行为的模拟以及此类种植体设计指南的制定。使用了二维和三维表示、静态和动态循环载荷、不同的材料模型、轴向载荷以及指向咬合角的载荷。采用了一种新型的小梁骨模型来纳入疲劳效应。还对方向性材料行为、渐进性骨丢失和部分骨结合进行了建模。与先前研究中使用的固定约束不同，使用弹簧约束对利用肌肉附着的骨支撑进行建模。来自Brånemark公司的锥形螺纹设计在骨中显示出比BUD医疗器械公司的平行轮廓螺纹更高的应力水平。BUD种植体的应力分布更均匀。对25%、75%和100%骨结合的研究表明，皮质骨承担了大部分载荷，由此产生的过载导致牙槽嵴骨丢失。应力图显示，随着牙槽嵴骨丢失的增加，大部分载荷直接转移到较弱的小梁骨组织。最后表明，通过适当的种植体重设计，载荷可以更均匀地转移到种植体上。这也提高了骨的疲劳寿命。
