Efeito da espessura de facetas oclusais confeccionadas em CAD/CAM e do substrato dentário sobre a resistência à fratura

Abstract

The aim of the study was to evaluate, in vitro, the fracture resistance of occlusal veneers, made by CAD/CAM, with Vita Enamic material in thicknesses of 0.6 mm and 0.3 mm bonded to enamel or dentin. Fifty human molars were randomly divided into five groups (n=10): G1 – sound teeth (control); G2 – 0.3 mm thick veneers bonded to enamel; G3 – 0.6 mm thick venners bonded to enamel; G4 – 0.3 mm thick veneers bonded to dentin; G5 – 0.6 mm thick veneers bonded to dentin. The venners were adhesively luted to enamel or dentin and stored in distilled water for 24 h. After storage, the fracture resistance test was performed in a universal testing machine with crosshead speed of 1 mm/minute. The fractures were classified as reparable and irreparable. Accoding to two-way analysis of variance (ANOVA), thickness fator (p=0.005) and substrate fator (p=0.004) were significant. The 0.3 mm thick veneers (2658 N) obtained greater fracture resistance, being significantly superior to the 0.6 mm thick veneers (2070 N). The veneers cemented to enamel (2648 N) had higher fracture resistance, being significantly superior to the veneers cemented to dentin (2049 N). The fractures were predominantly repairable. It was concluded that the Vita Enamic veneers with thickness of 0.3 mm provided greater fracture resistance, as well as the cementation performed in enamel.