Estimation Requiring Torque of Prosthetic Screw by Finite Element Analysis and Experiment

Abstract

The purpose of the study was to find the influence of screw tightening torque to the prosthetic screw and screw-retained abutment-implant complex in long-term using. In this study, a method of FEM simulation is presented to estimate a suitable tightening torque of prosthetic. Torsion test has been carried out to find the ultimate torque secondly. The results of experimental are compared with simulation ones and shows a good agreement. A FEM modelling of occlusal loading with considering tightening torque is performed to investigate the influence of tightening torque under external loading subsequently. And the safety factor of 107 cycles is calculated based on the present modelling to judge the reliability in long-term using. The result shows that tightening torque not only affect the stress of prosthetic screw significantly but also the stress of screw-retained abutment. According to the study, a tightening torque less than 18N⋅cm is recommended to use ensure the functionality of implant system.