Atrofik Total Dişsiz Maksillanın Dental İmplant Destekli Protetik Rehabilitasyonunda Uygulanan Subperiosteal İmplantlatın Ve Zigomatik İmplantların Konvansiyonel İntraosseoz Dental İmplantlar İle 3-Boyutlu Sonlu Elemanlar Stres Analizi Kullanarak Karşılaştırılması

Abstract

There are various treatment methods for the fixed prosthetic restoration of the totally edentulous atrophic maxilla. Applying conventional implant treatment together with bone augmentation is the most commonly used technique among these treatment methods. The use of autogenous bone graft in bone augmentation procedures is seen as the gold standard. Considering the size of the area to be grafted, the iliac bone is an ideal extraoral donor site. Reconstruction of the jaw bones with iliac bone graft is an invasive surgical procedure that should be performed under general anesthesia. After the operation, the patient needs to be hospitalized in the hospital. Long prosthetic rehabilitation time, high bone resorption in the healing period of the iliac bone graft, pain in the area where the graft is taken after the operation, nerve damage and gait disturbances are some disadvantages of the operation. In order to reduce all these disadvantages, the use of zygoma implants and subperiosteal implants in atrophic maxillas are presented as alternative methods in the literature. However, the response of zygoma and subperiosteal implants to occlusal forces is not fully known. In fact, the response of dental implants to occlusal forces affects long-term clinical results. The aim of our study is to examine the stress values of the iliac graft, zygomatic implant, titanium subperiosteal implant and polyether ether ketone (PEEK) subperiosteal implant under occlusal forces using the finite element stress analysis method to select the most accurate surgical technique for patients with total edentulous atrophic maxilla. In our study, a total edentulous maxilla model with advanced atrophy was created by using tomographic records in the computer environment. On this model, four different treatment plans were applied. The first maxilla model is the bone augmentation that is made with iliac bone graft and six dental implants are placed at the level of number 2,4 and 6 teeth. The second maxilla model, on the other hand, the bone augmentation which is made with ramus bone graft and two zygomatic implants are placed at the level of the number 6 tooth and four dental implants are placed at the level of the number 2 and 4 teeth. The maxilla with titanium subperiosteal implant is the 3rd model and the PEEK subperiosteal implant is the 4th model with the maxilla. In our study, Brånemark System (Nobel Biocare AB, Goteborg, Sweden) dental implants with a diameter of 3,75 mm and a length of 10 mm, and Brånemark System zygomatic implants with a diameter of 4,1 mm and a length of 35 mm (Nobel Biocare AB, Goteborg, Sweden) were used. In the created model, zygomatic implants were placed with the intrasinus technique. A force of 150 N was applied vertically and 50 N was applied obliquely at an angle of 30 degrees from the level of teeth 2, 4 and 6. The tensile and compressive stresses accumulated in the cortical and trabecular bone as a result of the applied forces and Von Mises stress values accumulated in the implant, abutment and metal infrastructure were investigated by finite element stress analysis. According to the results of our study, the highest compression stress on the bone was observed in the model with the subperiosteal implant produced with PEEK, while the highest tensile stress was observed in the maxilla model with the iliac graft. The stresses on the metal substructure were found mostly in the model with titanium subperiosteal implant. While the most stress under vertical forces was observed in the implants in the iliac graft-applied model, the highest stress under oblique forces occurred in the zygomatic implant-applied group. With these results, when the stress values occurring in bone, implants, abutment and metal infrastructure under functional forces in the four scenarios created for the fixed prosthetic rehabilitation of the atrophic total edentulous maxilla are considered, it is seen that it is not an ideal option as a treatment option. Therefore, each patient should be evaluated individually and the most ideal treatment option should be decided for the patient.