Kunavisarut Chatchai, Lang Lisa A, Stoner Brian R, Felton David A
Department of Prosthodontics, School of Dentistry, University of North Carolina, Chapel Hill, NC, USA.
J Prosthodont. 2002 Mar;11(1):30-40. doi: 10.1111/j.1532-849x.2002.00030.x.
The purpose of this study is to use finite element analysis to investigate the effect of misfit prostheses, cantilever prostheses, and various occlusal forces on the stress distribution in the prostheses, implant components, and surrounding bone.
Two 3-dimensional finite element models were constructed: (1) a 2-implant-supported, 2-unit fixed partial denture and (2) a 2-implant-supported, 2-unit fixed partial denture with a distal cantilever. Variations of the standard finite element models were made by placing a 111-microm gap between the gold cylinder on either the mesial or distal implant. The effects of load of 100 N were tested on all models. Subsequently, loads of 50 N, 200 N, and 300 N were evaluated on the cantilever model.
When the gap was positioned near to the applied force, the stress in both models increased significantly in the implant components and surrounding bone. The stress increase in each component ranged from 8% to 64% in the non-cantilever models and 43% to 85% in the cantilever models. The greatest stress was found in the distal gold screw. The effect of the gap was clearly shown by the pattern of stress distribution in both models. Additionally, the presence of a cantilever and excessive occlusal force amplified the effect of prosthesis misfit.
Prosthesis misfit influenced the pattern and magnitude of stress distribution in the prosthesis, implant components, and surrounding bone, and the presence of the cantilever or greater occlusal force amplified the effect of misfit.
本研究旨在运用有限元分析，探究不匹配假体、悬臂式假体以及不同咬合力对假体、种植体部件和周围骨组织应力分布的影响。
构建了两个三维有限元模型：（1）一个由两颗种植体支持的两单位固定局部义齿；（2）一个由两颗种植体支持且带有远中悬臂的两单位固定局部义齿。通过在近中或远中种植体的金圆柱体之间设置111微米的间隙，对标准有限元模型进行了改变。对所有模型测试了100牛的载荷效果。随后，对悬臂模型评估了50牛、200牛和300牛的载荷。
当间隙靠近加载力时，两个模型中种植体部件和周围骨组织的应力均显著增加。在非悬臂模型中，各部件的应力增加范围为8%至64%，在悬臂模型中为43%至85%。最大应力出现在远中金螺钉处。间隙的影响在两个模型的应力分布模式中清晰可见。此外，悬臂的存在和过大的咬合力放大了假体不匹配的影响。
假体不匹配影响了假体、种植体部件和周围骨组织中应力分布的模式和大小，悬臂的存在或更大的咬合力放大了不匹配的影响。
