Evaluation of the use of HİGH performance polymers as abutment material by finite element analysis

The aim of this study is to examine the stress distribution created by the Polyetheretherketone (PEEK) and Polyetherketoneketone (PEKK) as abutment material in the peripheral bone, in the implant and in the abutment screw. In addition, it is aimed to examine the stress changes that will occur in the peripheral bone around the implant, the implant and the abutment screw by using 5 mol.% yttiria partially stabilized zirconia (5Y-PSZ) as the monolithic superstructure material. Dental implants have been in use for a long time in order to restore teeth lost for various reasons, both functionally and aesthetically. The abutment and superstructure material used for the restoration of the lost tooth are of great importance in terms of both aesthetics and function. Instead of the gold standard titanium abutments, which have been used frequently for years, PEEK and PEKK abutments have been an alternative option, which does not contain metal, does not have the risk of corrosion, promises more aesthetic results and have shock absorption feature. In addition, the fact that they have an elastic modulus closer to dental tissues compared to zirconia suggests that they will be more advantageous material alternatives in terms of transmitted stress. Therefore, in this study, stress changes in the implant, peri-implant bone and abutment screw were investigated by using PEEK and PEKK materials as abutment materials. In this study, a maxillary model without maxillary right upper incisor was planned. A total of 4 different abutment materials, titanium, zirconia, PEEK and PEKK, and a single crown made of monolithic zirconia were designed on the titanium implant. In total, 4 different study groups were planned.178N force was applied from palatinal region and 2mm below the incisal edge at an angle of 45 degrees with the long axis of the implant, simulating normal chewing force. Finite Element Analysis (FEA) method is a numerical method that mathematically models and analyzes complex structures by breaking them into small elements. By using FEA, it has been possible to evaluate areas such as bone surfaces and implants surfaces that are very difficult to evaluate in vivo or in vitro. In this study, the three-dimensional FEA method was used to evaluate the stress that will occur in the peri-implant bone, implant and abutment screw. The stress values occurring in the monolithic zirconia crown in the study are similar and clinically acceptable values in all models. In addition, the lowest von Mises values observed in implant, abutment and screw are in the model with zirconia abutment. Abutments produced from PEEK and PEKK caused similar stress values in implant, screw, superstructure, cortical and cancellous bone. In addition, the highest stress value was found in the cortical bone in the model with PEEK abutment. It is thought that the use of PEEK and PEKK material in the selection of abutment material will affect the stress that will occur in the peri-implant bone, implant and abutment screw, and thus the success of the implant treatment. For this reason, it is expected to shed light on clinical applications in choosing which abutment and superstructure material to use according to the results of the study.