RESUMO
PURPOSE: To verify the effectiveness of a countertorque device in dental implants in redistributing stress to the bone-implant interface during tightening of the abutment screw. MATERIALS AND METHODS: Two prismatic photoelastic samples containing implants were made, one with a 3.75-mm-diameter implant and the other with a 5.0-mm-diameter implant (both implants had an external-hexagon interface) and the respective abutments were attached (CeraOne). The samples were placed in a support and submitted to torques of 10, 20, 32, and 45 Ncm with an electronic torque meter. The torque application was repeated 10 times on each sample (n = 10) with and without a countertorque device. Photoelastic patterns were detected; thus, a photographic register of each test was selected. The fringe patterns were analyzed at discrete points near the implants' external arch. RESULTS: In both implants analyzed, a stress gradient reduction was observed through the implant with the countertorque device. CONCLUSIONS: The countertorque device used in this study proved to be effective in reducing the stresses generated in the peri-implant bone tissue during torque application.
