Stress distribution in the transitional peri-implant bone in a single implant-supported prosthesis with platform-switching under different angulated loads.

A 3D finite element analysis was conducted to evaluate and compare the stress distribution in the peri-implant bone (transitional cortical and trabecular bone) of one single implant-supported crown with platform switching and another without platform switching, under a vertical and an oblique load. Two models were created, simulating an osseointegrated implant (4 × 13 mm, platform 4.1 mm) embedded in the jaw bone. One model simulated a 4.1-mm diameter abutment connection (conventional model) and the other a 3.8-mm diameter abutment connection (platform-switching model). A crown with a Co-Cr alloy framework and feldspathic porcelain veneering was applied over the titanium abutment. Static, vertical and oblique loads (0°, 15°, 30°, 45°) with a maximum value of 150 N were applied to the crown. For any inclination of the applied load, the stress values in the transitional cortical bone were lower in the platform-switching model than in the conventional model. However, the stress in the transitional trabecular bone was higher in the platform-switching model than in the conventional model. Stress values increased when the load was more oblique at the transitional cortical bone in both models and was slightly reduced at the transitional trabecular bone of the conventional model. The platform-switching technique reduces the stress at the transitional cortical bone. In both models, this stress gradually increases as the load becomes more inclined. The transitional trabecular bone shows lower stress values than the transitional cortical bone. The location of stress is similar in both models.