Effect of platform switching on peri-implant bone: A 3D finite element analysis

Statement of problem. A consensus regarding the effects of platform switching on peri-implant marginal bone levels is lacking. Finite element studies have reported contradictory results. Purpose. The purpose of this finite element analysis study was to evaluate stress distribution in platform-switched (PS) and platform-matched (PM) implants and their surrounding bone. Material and methods. An implant (4.5x11 mm) was modeled and screwed into a human mandibular bone block using a computer-aided design (CAD) software program. Two separate models were generated: (1) PM, 4.5-mm implant with 4.5-mm-wide abutment and (2) PS, 4.5-mm implant with 3.5-mm-wide abutment. Implant components were modeled with linear isotropic properties and bones with anisotropic properties. Vertical (200 to 800 N) and oblique (50 to 150 N) forces were applied to each model to simulate occlusal loads. Linear elastic analysis was performed using ANSYS Workbench 16. von Mises equivalent stresses in the implant assemblies and peri-implant bone were calculated and compared with independent samples t test (alpha=.05). Results. von Mises equivalent stress values under simulated axial and nonaxial occlusal loads were lower for PM than for PS implant assemblies. However, the differences were not statistically significant. Stress within the peri-implant bone was significantly higher for the PM group than for the PS group (P<.001). Conclusions. Platform switching decreased stress within peri-implant bone and may help limit marginal bone resorption.