Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
Clin Implant Dent Relat Res. 2010 Jun 1;12(2):105-13. doi: 10.1111/j.1708-8208.2008.00142.x. Epub 2009 Feb 13.
Understanding how clinical variables affect stress distribution facilitates optimal prosthesis design and fabrication and may lead to a decrease in mechanical failures as well as improve implant longevity.
In this study, the many clinical variations present in implant-supported prosthesis were analyzed by 3-D finite element method.
A geometrical model representing the anterior segment of a human mandible treated with 5 implants supporting a framework was created to perform the tests. The variables introduced in the computer model were cantilever length, elastic modulus of cancellous bone, abutment length, implant length, and framework alloy (AgPd or CoCr). The computer was programmed with physical properties of the materials as derived from the literature, and a 100N vertical load was used to simulate the occlusal force. Images with the fringes of stress were obtained and the maximum stress at each site was plotted in graphs for comparison.
Stresses clustered at the elements closest to the loading point. Stress increase was found to be proportional to the increase in cantilever length and inversely proportional to the increase in the elastic modulus of cancellous bone. Increasing the abutment length resulted in a decrease of stress on implants and framework. Stress decrease could not be demonstrated with implants longer than 13 mm. A stiffer framework may allow better stress distribution.
The relative physical properties of the many materials involved in an implant-supported prosthesis system affect the way stresses are distributed.
了解临床变量如何影响应力分布有助于优化义齿设计和制作，并可能减少机械故障，提高植入物的使用寿命。
本研究通过三维有限元法分析了种植体支持义齿的许多临床变化。
创建了一个代表接受 5 个种植体支撑的框架治疗的人类下颌前牙段的几何模型来进行测试。计算机模型中引入的变量包括悬臂长度、松质骨弹性模量、基台长度、种植体长度和支架合金（AgPd 或 CoCr）。计算机根据文献中得出的材料物理特性进行编程，并使用 100N 的垂直载荷模拟咀嚼力。获得具有应力条纹的图像，并将每个部位的最大应力绘制在图表中进行比较。
应力集中在最接近加载点的元素上。发现应力增加与悬臂长度的增加成正比，与松质骨弹性模量的增加成反比。增加基台长度会导致种植体和支架上的应力降低。植入体长度超过 13mm 时，无法证明应力降低。更硬的支架可以更好地分配应力。
植入体支持义齿系统中涉及的许多材料的相对物理特性会影响应力的分布方式。
