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An Overload Failure of a Dental Prosthesis: A 3D Finite Element Nonlinear Contact Analysis


 Dental implants are extensively used to treat fully and partially edentulous patients. However, the success rates of clinical cases involving partially edentulous patients is lower than the fully edentulous cases.1 In one partially edentulous case that we have been examining, a prosthesis was supported by two screw-shaped, 3.75mm diameter Branemark implants as shown in Figure 1. The implants were separated by 7mm and were located in the molar region of the mandible. After the insertion of the implants and a healing period of 6 months, the prosthesis was put into function. After 3 months of loading, there was significant bone loss near the mesial implant which eventually lead to its mechanical failure. We have previously made a biomechanical analysis of this failed implant case using analytical2 and 3D finite element (FE) analysis.3 In the previous 3D FE study, the interface between the implant and the bone was assumed to be fully bonded. In this current investigation, the assumption of bonding vs no bonding is further investigated using 3D contact analysis. Surface to surface contact is a phenomenon that occurs between two contacting surfaces which are close to each other and might be in contact or separated depending on the interfacial stresses between the two surfaces. In this study the contact analysis is used to capture the bonding and non bonding between the bone and the implant interface.