Document Type : Original Articles

Abstract

Introduction: Mean bar failure in overdenture-supported implant has been reported to be 3.97 percent; even this low failure rate is unacceptable for patients because of its cost compared with complete denture. The aim of this study was to assess stress distribution in different points of the bar of overdenture-supported implants by finite elements analysis.  Materials and methods: In this descriptive study, stress distribution on the bar of mandibular overdenture was evaluated by the finite elements analysis (FEA). Implants in two canine areas were connected to each other by one bar at the distance of 2 mm from the lining tissue of the edentulous ridge. Then the vertical force applied to the left first molar increased gradually from 0.5 to 50 N and stress distributions were recorded at different points of the bar.Results: By increasing the force up to 6.06 N, stress was uniformly distributed over the bar, but with greater force stress was focused on the border of the middle third and the force application third. This pattern of stress distribution continued parallel with an increase in the force. Conclusion: Failure is higher at the border area between the middle third of the bar and the third near the applied force due to maximum stress; therefore, reinforcement of the bar at this area is suggested Key words: Attachment, Dental stress distribution, Finite element analysis, Overdenture, Supporting bar.