The Influence of Design on Stress Concentration Reduction in Dental Implant Systems Using the Finite Element Method

Dental implant fracture is closely connected to the stress buildup surrounding the implant system during static loading. In areas where the cross-section of the implant rapidly changes or where the geometry of the implant system has discontinuities, stress concentrations arise. Therefore, the implant's design is crucial in preventing early failure of the implant system, including fracture, screw loosening, and increased leakage, in addition to reducing stresses at the implant-abutment interface. In the current work, three-dimensional (3D) models of mechanically connected Ti6-Al-4V implant systems in various dimensions were constructed. Finite element analysis (FEA) was used to conduct a stress study of the created implants under actual acting force static loading conditions in accordance with ISO 14801. In the created models, design elements including implant screw type, thickness, and taper angle of abutment were modified in order to increase the longevity of the implants. The results show that the equivalent stress level was dramatically reduced from 596.22 MPa to 212.72 MPa in the implant model, which exhibits a more homogeneous stress pattern under static loading conditions. By increasing the implant wall thickness from 0.15 mm to 0.40 mm in the region adjacent to the abutment, the stress levels, especially at the internal screw, were significantly reduced. Also, the design modification in Model B, establishing contact between the abutment and the upper part of the conical surface of the implant, resulted in a decrease in stress in the internal screw. Thus, enhanced homogeneity in stress distribution not only improves the harmony between the implant and surrounding tissues, thus increasing patient comfort and reducing the risk of complications, but also holds promise for the development of new implants capable of withstanding the forces encountered in the oral environment due to the relatively smoother stress transmission observed in this model.