Finite Element Analysis of the Effect of Tightening Torque on the Connection Stability of a Two-Piece Zirconia Implant System

Purpose. Loosening and fracture of abutment screws are one the most common complications in implant-retained fixed prostheses. Thus, applying proper tightening torque to screw is important for preventing loosening effect ensuring stability implant fixture-abutment connection. Therefore, this study, we aimed investigate on connection a two-piece zirconia system using finite element analysis (FEA). Materials Methods. The structures used study were designed CATIA program. with torques 25 (TT-25), 35 (TT-35), 45 (TT-45) N·cm assumed fix fixture. Vertical (200 N) oblique (100 loads applied model generated FEA simulation, stress levels distributions investigated. Results. TT-45 group exhibited highest von Mises fixture, followed by TT-35 TT-25 groups. minimal principal stresses also group, In all three groups, area concentration was located at point contact bottom head. Furthermore, showed safety factor value. value similar safe minimum standard, while lower Conclusion. When N cm system, it maximum close 660 MPa (75% yield strength Ti-6Al-4V alloy), which optimal preload recommended screws.