The effect of different materials and multi-unit angles in stress distribution on implant-supported fixed bridges: A finite element method study

Aim: In implant-supported restorations, various abutment angulations can be used. These angles are determined based on factors such as the structure of the jawbone, the position of the implants, and the design of the restoration. The aim of this study is to evaluate the effect of multiunit abutment angles on stress patterns of the implant and the peri-implant tissue. Methodology: In this finite element analysis study, three different three-dimensional models of maxillary 3-unit fixed implant-supported prostheses were examined. A jawbone was created with jaw components in SOLIDWORKS. Subsequently implant models obtained from an implant company(Bilimplant®) were placed in the area of the maxillary premolar, and the other implant were placed in the area of the maxillary first molar. Multiunit abutments were used at three different angles (0°, 15°, 30°). Two different restorative materials (Co-Cr feldspathic and zirconia feldspathic) were designed in EXOCAD software for the fixed implant-supported restoration. 150 newtons at a 30-degree angled oblique force was applied to the implants. Subsequently, stress distribution was evaluated with finite element analysis and performed using the ABAQUS software and analyzed with Von mises stress distribution. Results: With the increase in the multiunit angle in implant-supported prostheses, it has been observed that the stress values applied to the implant components and cortical bone increase, while the stress applied to the prosthesis decreases. The highest stress values on implant components and cortical bone were detected in the zirconia framework models. Conclusion: This study evaluates the impact of multiunit abutment angles on implant-supported restorations and examines the stress patterns of implants and peri-implant tissues. The study shows that increasing the multiunit angle in implant-supported prosthesis increases stress values on implant components and cortical bone while decreasing stress applied to the prosthesis.