Prostheses supported by implants directly transmit the occlusion loads to the adjacent peri-implant bone, and this can result in complicated patterns of stress distribution affecting long-term implant stability. The biomechanics of stress transfer to the dental implants during complete denture loading and the effects on long-term stability of the implants through the use of a finite element analysis technique. A 3D finite element model of an edentulous mandible provided with an implant-supported complete denture of 30 dental implants was developed. Vertical and oblique conditions of static loading were used to simulate functional masticatory forces. Stress distribution and peri-implant bone strain criteria of von Mises stress and maximum principal strain. Oblique loading induced a general increase in the values of peak stress and strain, with the highest degrees of concentration in crestal cortical bone around the posterior implants. Although the high number of implants led to an improvement in global load distribution, the localized stress magnification under applied oblique loads was observed. Cortical bone was invariably subjected to more stress than cancellous (41%), as in all cases it was associated with increased disposition to biomechanical overload. A simple rise in the number of implants is not the solution to biomechanical risk, and indicates that optimized loading direction and distribution of implants are necessary; also, it notes the design of the prostheses as one of the major determinants of long-term clinical outcomes.
