Distribution of load in an oral prosthesis system: an in vitro study

Although the long-term success of osseointegrated endosseous implants for the support of fixed dental prostheses has been reported, the increasingly routine and widespread use of implant-supported prostheses has led to problems associated with their structural integrity. To assess the service life of the components of the prosthetic system, a knowledge of the loads transmitted through the system is needed. This paper reports in vitro findings for forces and bending moments transmitted through the abutments from a fixed dental prosthesis to its supporting implants. The results have been compared to previous theoretical analyses that generally overestimate the maximum tensile forces. The effect of the length of distal cantilevers and of missing gold screws as the result of loosening or fracture is also considered. It is proposed that bending moments may play a larger role in failures than previously believed.