İliak Kemik Grefti ile Rekonstrükte Edilmiş İleri Derecede Atrofik Mandibula Modelleri Üzerindeki Stres Dağılımının Sonlu Elemanlar Analizi ile Değerlendirilmesi

Abstract

Dental implant therapy have become an often used alternative to replace missing teeth. Biomechanical factors have an important influence on the long and short term success of the dental implant. Factors such as implant macro-geometry, implant material properties, crown-height space, quality and quantity of surrounding bone affect the stres distrubiton around peri-implant bone. Increased crown-height space compromise prosthetic rehabilitation of severely atrophic alveolar ridges. Different treatment approaches are available to overcome this problem. Although the placement of endosseous implants following augmentation procedures is a traumatic way of treatment, it has been used widely. The alternative approach is short implants, which have become popular in recent years. The aim of this study is to analyze and compare stres intensity, distribution and localization on the implants and abutments and peri-implant cortical and cancellous bone when loaded in vertical and oblique directions on severely atrophic mandible models treated with alternative treatment protocols (augmentation procedures or short implants). Three different bone models were generated: Standart mandible, severely atrophic mandible with bone augmentation procedure and severely atrophic mandible model. Standard and short cylindrical endosseous implants were virtually placed to mandibular 1st molar region and 150 N vertical and 50 N oblique forces were applied. Stress values and distributions on the implants, abutments and periimplant cortical and cancellous bone were analysed using finite element analysis method. 10 mm implant length were placed in the standard mandible model, 6 mm implant length were placed in the atrophic model. The reconstructed mandible model consisted of 6 mm mandibular bone and 4 mm iliac bone was generated to be able placed 10 mm implant length. In the standard model, the implant length was accepted as 10 mm and the crown height space was accepted as 8 mm. Maxillary occlusal plane was constricted to standardise total implant and crown height. The crown length of the models were 8 mm for reconstructed model, 12 mm for atrophic model. Stress values and distributions of each model was also evaluated for three different crown heights (8, 10 and 12 mm). This study was carried out through three-dimensional finite element analysis with static linear analysis. According to the results of the study, stres values in the cortical bone and cancellous surrounding implants placed in the reconstructed mandible model and the atrophic mandible model were similar. The highest stres values on the abutments were measured in the atrophic mandible model. Stress values on the implants were similar implants placed in the reconstructed mandible model and the atrophic mandible model. It was also observed that oblique forces generated higher stres values than vertical forces.