Investigation of stress distribution in natural tooth-implant supported fixed prostheses of abutments made of different materials with different implant-abutment connection types finite element analysis method

This study aimed to investigate the stresses generated in natural teeth, dental implants, connecting screws, abutments, prosthetic materials, and bone under forces applied to different implant-abutment connection types and abutment materials with different elastic moduli in fixed prosthetic restorations supported by natural teeth and dental implants, using finite element stress analysis. Three-dimensional computer models were created to simulate a three-unit fixed prosthesis supported by a natural tooth number 44 and a dental implant in region 46, along with the surrounding bone. Titanium (Ti), zirconia (Zr), and hybrid (H) abutments were used as abutment materials in these 3D models. Additionally, external hexagonal (EH), internal hexagonal (IH), and Morse taper (MT) connection types were employed. In our study, while the periodontal ligament was modeled nonlinearly, the natural tooth, dental implant, connecting screw, abutment, prosthetic material, and bone were modeled linearly. Vertical and oblique forces of 100 N and 200 N, respectively, were applied to each premolar tooth and molar tooth, resulting in a total force of 400 N. The Von Mises stresses generated by these forces in the cortical and trabecular bone, natural tooth, dental implant, connecting screw, abutment, and prosthetic material were analyzed. The results showed that stresses generated by both vertical and oblique forces were higher in the cortical bone than in the trabecular bone in all models. Furthermore, stresses were found to be more concentrated in the cortical bone around the dental implant compared to the natural tooth. Lower stress values were observed in the cortical bone in models with Morse taper connections under both vertical and oblique forces. Stresses in the natural tooth, connecting screw, and implant were higher in models with Morse taper connections, particularly concentrating in the neck region of the implant. Models using zirconia abutments, a more rigid material compared to titanium, exhibited higher stress values under applied forces. In conclusion, this study demonstrated that both the direction of the applied force and the type of implant-abutment connection and abutment material affect the stress values generated in natural tooth-supported dental implant prostheses.