Finite element analysis of bone resorption risk and stress distribution in anterior restorations supported by hybrid abutments produced using CAD-CAM systems

The purpose of this study was to evaluate the stress distribution caused by different CAD-CAM abutments in immediate and delayed loading procedures in the maxillary central tooth area. Six different hybrid abutment models [titanium (control), zirconia, lithium disilicate, polymer-infiltrated hybrid ceramics, polyetheretherketone, and polymethyl methacrylate] were created. The von Mises stress values of the implant, Ti-base, implant screw, abutment, and crown, as well as the maximum and minimum principal stress values formed in the cortical and trabecular bone and the bone resorption risk index were evaluated. The highest stress values were observed in the implant, Ti-base, bone, and crown in the polymethyl methacrylate abutment, while the lowest values were observed in the zirconia abutment. The von Mises stress values in the immediate loading group were found to be lower than those in the delayed loading group. The bone resorption risk has been found to be higher in immediate loading.