HOW IMPORTANT ARE THE IMPLANT INCLINATION AND THE INFRASTRUCTURE MATERIAL USED IN IMPLANT SUPPORTED FIXED PROSTHESES?

Objectives: The aim of this study is to evaluate the stress , which is caused by the fixed prosthesis under oblique forces around dental implants and bone by using different infrastructure materials and different inclusions, by 3-dimensional finite element analysis method. Materials and Methods: The 3D finite element models of the mandible, dental implants and prostheses were prepared. The anterior and posterior implants were designed 10 mm in length and 4.3 mm in diameter. The anterior implant was placed parallel to each model. Posterior implant designed to make inclinations those mesial 17, distal 17, buccal 17, lingual 17. Implant supported fixed restorations were divided into 3 main groups according to the infrastructure materials. These materials were; chromium-cobalt, zirconia, polyetheretherketone (PEEK). In each model, a total of 500 N oblique force was applied from the buccal tubercle crests to the buccolingual direction at an angle of 30 degrees to the long axis of the tooth. Maximum principal stress and minimum principal stress values in the bone models were taken. In addition, maximum von Mises stress values were obtained from implants and substructure materials. Results: When the stress findings in the mandible during oblique loading were evaluated, it was found that the stresses on the cortical bone were higher than the stresses on the trabecular bone. It was observed that the highest stress values occurred in the implants. Conclusions: It is thought that chromium-cobalt and zirconia-based ceramic bridge restorations are more positive in terms of stress distribution than PEEK-based ceramic bridge restorations.