Comparison of stress induced in mandible around an implant-supported overdenture with locator attachment and telescopic crowns - a finite element analysis.

INTRODUCTION: One of the principle factors for the success of implant supported/retained overdentures (IOs) is the manner in which the stresses are transferred to the surrounding bone. Hence, the aim of the present study is to compare the stress induced in the mandible around IOs, using two different attachment systems, locator and telescopic. METHODS: 3D finite element models were prepared using Pro/ENGINEER or PTC Creo to simulate 4 clinical situations: IOs using two different attachment systems, locator and telescopic, with and without splinting. A vertical compressive load of 35N was directed toward the central fossa in the molar region of each overdenture. Non-linear static contact analysis was carried out to determine the stress distribution in various components of IOs. Then, the models were analyzed by a finite element program ABAQUS, and displayed using Von Mises stress patterns. RESULTS: The contact stress values developed on the implant and attachment components were lower with locator attachment, in both splinted and non-splinted models. On the other hand, the stress distribution to the cortical bone was more with non-splinted/splinted locator attachments (3.73/4.12 Mega Pascals) when compared to the non-splinted/splinted telescopic attachments (2.66/3.7 Mega Pascals). The stresses in all the components of overdenture were greater with the splinted model compared to non-splinted, in both the attachment systems. CONCLUSION: The locator attachment might demonstrate superior clinical performance, as the stresses on implant and attachment components were less compared to telescopic. Non-splinted model showed better results in both the attachment types.