Investigation of stress distribution in dental-implant supported fixed dentures manufactured with different infrastructure materials by finite element analysis method

The aim of this study is to investigate the effect of different prosthetic materials with different modulus of elasticity used in tooth-implant supported fixed prosthetic restorations on stress distribution and magnitude of teeth, dental implants, connection screws, abutments, prosthetic material and bone using final element stress analysis method. Three 3D models containing three-unit fixed prosthesis supported by natural tooth 34 and dental implant placed in region 36, and bone section surrounding this prosthesis were created virtually in the computer environment. Cobalt-chromium (Co-Cr), zirconia (Zr) and polyether ether ketone (PEEK) were used as prosthetic materials in these three-dimensional models. In this study, while the periodontal ligament was modeled non-linearly, natural tooth, dental implant, connection screw, abutment, prosthetic material and bone were modeled linearly. A total force of 400 N was applied to the models in vertical and oblique directions; each 100 N on the premolar teeth and 200 N on the molar tooth. Maximum-minimum principal stresses created by these forces in cortical and trabecular bone and Von Mises stresses created in natural teeth, dental implants, connection screws, abutments and prosthetic materials were investigated by finite element stress analysis method. In our findings, the Von Mises stresses on the natural tooth, prosthetic restoration and connection screw as a result of vertical and oblique force applications and the minimum principal stresses on the peri-implant cortical bone were found to be higher in the model using PEEK material than in the other models. As a result of vertical force application, while the minimum principal stresses have a similar distribution of all regions in the peri-implant cortical bone of the models in which Co-Cr and Zr materials were used, the stresses were concentrated in the distal part of the peri-implant cortical bone in the model in which the PEEK material was used. In all models, stresses created by the oblique forces on the cortical bone were measured higher than the vertical forces. As a result of this study, it has been observed that the use of Zr and Cr-Co, which are more rigid materials compared to PEEK material, positively affect the distribution and magnitude of stresses in natural tooth-dental implant supported fixed prostheses. The use of prosthetic materials with a high modulus of elasticity in natural tooth-dental implant supported fixed prostheses may be more advantageous in terms of biomechanics.