Analise biomecanica do efeito da esplintagem e da conexao protetica em implantes extra-curtos

Abstract

The aim of this study was to evaluate the stress distribution on extra-short implants in cases of mandibular bone atrophy, with the use of different implant-abutment connections (Morse Taper - MT and External Hexagon – EH), associated with two crown designs (single-unit or splinted). A three-dimensional segment of the mandible was constructed, based on a computed tomography image. Four configurations of two extra-short implants in the mandibular first and second molar region were modeled, with variations in the implant-abutment connections and crown designs. The models were loaded with normal masticatory force. The values of maximum (σmax), minimum (σmin) principal, shear stress (τ) and maximum strain (εmax) were analyzed for the bone tissue and the values of equivalent von Mises stress (σvM) for the structures of the implants, prosthetic screws and abutments. The MT connections showed the highest peaks of stress when compared to EH connections for implants, prosthetic abutments, prosthetic screws and bone tissue. Splinted crowns, irrespective of the implantabutment connection, showed lower peaks of stress when compared with the groups with single-unit crowns, both for implants and for abutments, prosthetic screws and bone tissue. The EH showed better biological behavior when compared with MT, irrespective of crown designs. Splinted crowns in the posterior region of the atrophied mandible appeared to allow better distribution of stresses to the prosthesis/implant system and bone tissue. The implant-abutment connection had an influence on the biomechanical behavior of the prosthesis/implant system, with better results being observed with the association of the EH connection with splinted crown.