AVALIAÇÃO DO EFEITO DO PROTOCOLO ADESIVO NA RESISTÊNCIA DE UNIÃO DE CIMENTOS RESINOSOS EM COMPÓSITOS CAD/CAM

Abstract

The objective of the present study was to evaluate the effect of different adhesive protocols on the bond strength of different CAD / CAM composites by means of the micro-shear test (μSBS). For this experiment, three types of CAD / CAM composites were used: 1) [Lava ™ Ultimate CAD / CAM Restorative (3M ESPE) - LU], 2) [Brava block CAD / CAM (FGM) Vita Enamic (Vita Zanhfabrik) - VE]. Forty-five rectangular sections (10 × 10 × 6 mm) of CAD / CAM composites were used for the evaluation of micro-shear, these blocks were distributed according to the following variables: CAD / CAM composites (1 LU, 2-BR, 3 - VE) vs. (1) Prime & Bond Elect (PBE) + Enforce, 2- Scotch Bond Universal (SBU) + Rely X Ultimate, 3- Ambar Universal + All Cem, 4- Silane without MDP + Enforce, 5- Silane without MDP + Rely X Ultimate, 6- Silane without MDP + All Cem, 7- Silane with MDP + Enforce, 8- Silane with MDP + Rely X Ultimate, 9- Silane with MDP + All Cem], resulting in 27 experimental groups . The adhesive system was applied and Tygon matrices were filled with resin cement and photoactivated. The specimens were stored in water (37 ° C for 24h) and submitted to the μSBS test, their results were submitted to the 2-factor ANOVA test followed by the Bonferroni test, α = 5%). Fifteen additional rectangular sections were evaluated in Scanning Electron Microscopy (SEM / EDS) for analysis of morphology and composition after surface treatment as recommended by each manufacturer. For the three cements used, higher values of μSBS were observed on the VE surface, followed by LU and BR respectively. The significant difference between the cementation systems was observed only in the composite VE, which presented higher values of μSBS, except for the silane groups with MDP + All Cem, silane without MDP + Rely X Ultimate and SBU + Rely X Ultimate. A higher percentage of adhesive / mixed failure was found for all groups, except for the VE / AU and VE / silane groups with MDP / All Cem, VE / silane without MDP and VE / SBU / Rely X Ultimate and VE / AU and VE / silane with MDP / Enforce, in which a higher percentage of cohesive failure was found in CAD / CAM composites. All the composites presented irregularities after the surface treatment in the SEM analysis, but greater irregularity was observed on the surface of the VE, followed by the LU and the BR respectively. The EDS analysis confirmed the composition of each CAD / CAM composite and after the surface treatment, the percentage of silica and zirconia was reduced only for LU. It can be concluded that the effectiveness of the cementation protocol is related to the type of CAD / CAM composite and its different compositions and that regardless of the cementation protocol, the VE presented the best values of micro-shear strength compared to other CAD / CAM composites evaluated.