An investigation of three dimensional finite elements analysis of bone resorption at the neck area of two different implant systems which switch platform feature on different bone density

In Oral and Maxillofacial surgery, there has been an increasing number of study related to dental implants for 1970s. Several biomechanical factors have been identified for short and long term success of dental implant which has become common. Although the success rate of these implant are related to the amount and quality of jaw bone, the design, surface structure of dental implant and surgical procedure; at long term success the effect of biomechanical factors are indisputable. Because of this we are planning to do research about the neck design which is the most important of biomechanical factor of dental implants and done a lot of study and commented. The most important factor which reason the failure of implant, is the resorption of bone at the neck area. In recent years; the implant which has switch platform has been introduced to the market by company for decreasing bone resorption. In this study; we aim to implement two different implant systems; which have switch platform feature; to distinct bone structure and investigate bone resorption at the neck area of implant under angled forces and compare with each other. Our in vitro study total 4 different diameters implant; which have 2 different lengths; will be selected. The models will be obtained by implementing these 4 different size dental implant in maxilla and mandible. These models will be implemented by vertical and oblique forces and the study groups will be created. As a result of the applied forces; the Von Misses stress at the implant and the tensile stress which occurs at cortical and cancellous bone will be analyzed by Finite Elements Method (FEM). In this study, as well as the osseointegration of implants with the bone, what the extent the resorption at the neck area of the implants which have switch platform will be investigated. The aim of this study is to predict what type of implant will be implanted in the clinical environment and to predict when bone loss will occur. It is also aimed to determine which type of neck design can be preferred, which implant size and length are most suitable for bone structure, and how to reduce the failure of implant applications by making them correct. In our study, we used 2 different implant models with platform switching design. Of these, Tapered Internal Plus Implant (TIPI; Biohorizons®, USA); 3.8 mm, 4.6 mm in diameter and 10.5 mm in length, and the second model was Dual Fit Implant (DF; Alpha-BioTec®, Israel); 4.75 mm, 4.2 mm in diameter and 2 in length of 10 mm. Maxillary and mandibular bone models were designed for placement of implants. Using the Next Engine 3D laser scanner and Rhinoceros 4.0 software program, endosteal implants, abutments (straight and 25⁰ angled) and prosthetic top structures were transformed into a 3D solid model in a computer environment. In the prosthetic superstructure, a total of 32 models were obtained and 70 analyzes were performed by applying force to the vertices and oblique (30⁰ angle) from specific points. As a result of our research, we determined Von Misses stress values on the bone around the implant and on the surface of the implants and displayed their color scales. The resulting data are explained by creating tables. As a result; we found that forces from vertical and oblique directions lead to stresses on the bone and implant surface in the neck region of implants placed in vertical and oblique positions. Von Misses stress values in the cortical bone around the implant's cortical module (neck part) showed a significant increase in the forces applied to the oblique direction when the oblique and vertical loads applied to the bone models were compared. In our study, the forces applied to both implant models and implant placement positions resulted in minimal stress distribution, implant and force being applied in the same direction. However, in the groups obtained with angled orientation of force and angled insertion position of the implant, the maximum Von Misses stress value changed the bone resorption around the implant neck to increase the resorption. We consider that stress analysis studies on implants that are widely used clinically will guide the clinician in terms of implant surface, neck properties, platform options and application protocols and raise awareness and success in implantology. Keydwords: Finite Elements Stress Analysis, Dental Implant, Platform Switching, Bone Density, Stress Distribution.