3D Finite Element Stress Analysis of an Implant Supported Overdenture Under Bruxism and Lingualized Loading Conditions

Bruxism is a nonfunctional motor activity that is characterized by grinding and clenching of the teeth. It has been postulated that bruxism causes excessive occlusal load on the dental implant and its superstructures leading to biological and biomechanical complications. While many researchers suggest that grinding/clenching causes early implant complications and accelerated bone loss, others indicate that the long term effects are still unclear. The goal of this study is to analyze the effect of bruxism loading condition on the stress distribution of an implant supported overdenture (ISO) using finite element analysis (FEA) and compare the results with one of the most functionally efficient occlusion schemes in the clinical dentistry — lingualized occlusion. A high fidelity solid model of a mandibular denture encompassing lingual and buccal cusps, mesial and distal fossae supported by four implants and a connecting titanium prosthetic bar, resting on alveolar bone were modeled in SolidWorks 2013 following proper clinical guidelines and imported to ANSYS 15.0 for stress analysis. The results of the study demonstrate that the stress distribution in the implant prostheses and surrounding bone is significantly affected due to bruxism as compared to the lingualized loading. While the location of the maximum stress concentration was the same (neck of the posterior implants) for both loading conditions, there was an increase of approximately 115% von-Mises stress for bruxism loading condition as compared to the lingualized occlusion. The maximum principal stress in the cortical bone surpassed the ultimate tensile strength limit of the jaw bone implying possibility of bone resorption in the peri-implant area.