Análise de sistemas de implantes dentários em mandíbulas edêntulas com aplicação de carregamento imediato

Abstract

The present study aimed at obtaining comparative elements among the guided systems of fixed complete denture with 4 osseointegrated implants with immediate loading, considering the importance of understanding the implant project as a process where biomaterials and biomechanics are assessed. The three-dimensional finite element method was used to analyze the stress concentrations in the whole implant-supported system, associated to the variation of the material of the prosthetic bar among the nickel-chromium, cobalt-chromium and Ti-6Al-4V alloys. Metallographic tests of the Ni-Cr and Co-Cr alloys, were made with the objective of identifying the micro-structure and consequently evaluate its influence in the mechanical behavior of the system. Two systems were analyzed, one with cantilever and another without it, but with tilted implants, submitted to a vertical load of 756N on the superior face of the prosthetic implant-supported bar. Parallel to this study the prosthetic groups (screw-abutment-implants) straight and tilted were also separately verified, submitted to a vertical load of 100N on the top of the abutment. The data found were compared and assessed according to values obtained in the literature. The results demonstrated that the use of tilted implants avoiding the use of cantilever reduced considerably the stress levels in the prosthetic bar and in the abutments. However, in the implant-bone area an increase of approximately 1.5 times in stress levels was observed, compared to the straight implant under cantilever. The study of the alloys apponted the Co-Cr alloy as a material comparable to the other ones, regarding the mechanical behavior