The Effect of Cantilever Planning on Stress Distribution in Implant-Supported Prostheses.

Abstract

This finite element analysis (FEA) study investigates the effects of different cantilever designs on stress distribution in implant-supported partial fixed dental prostheses. Three models were analyzed in the posterior mandible: Model A with a distal cantilever, Model B with a mesial cantilever, and Model C with no cantilevers. Each model included a four-unit monolithic zirconia prosthesis supported by two implants. Under a 200 N oblique load, stress distribution was analyzed in the cortical and trabecular bone, implant components, cement layer, and prosthesis. Fatigue performance was assessed using material-specific S-N curves and fatigue equations. The results demonstrated that models with cantilever extensions exhibited increased stress accumulation, particularly in components adjacent to the cantilever. The highest von Mises stress values were observed in Model A, especially on the distal abutment (721.2 MPa), distal implant (313.7 MPa), and prosthetic structure (409.9 MPa).In contrast, Model B showed a more balanced stress distribution and lower stress levels than Model A. The findings suggest that cantilevers' presence and positioning significantly impact implant supported prostheses' biomechanical behavior. With its shorter lever arm and more favorable force distribution, the mesial cantilever was a safer and more effective design option than the distal cantilever, reducing the risk of mechanical complications. These results emphasize the importance of careful design and engineering calculations when planning implant-supported prostheses to ensure long-term stability and minimize the likelihood of failure. This study highlights the biomechanical implications of cantilever positioning in implant prostheses.