Influência do protocolo adesivo na resistência de união de reparos em resina composta

Abstract

This study evaluated the influence of the adhesive protocol employing silane and universal adhesive with and without aging on the bond strength of composite resin repairs. A universal adhesive (AU) and different types of silane bonding agents, pre-hydrolyzed (PH) and immediate hydrolysis (HI) associated with conventional adhesive, were tested on composite resin repairs. The specimens were prepared with composite resin incorporated into polystyrene resin and aged for one month in distilled water at 37°C. Half of the silane agents and the universal adhesive were subjected to aging process (48°C/1 month), while the other half was used without aging. The composite resin specimens were sandblasted with aluminum oxide for surface treatment and cleaned with phosphoric acid. Then, the different silane systems (PH or HI) associated with conventional adhesive were applied according to the groups. For AU, a layer of silane was not applied beforehand. Four cylinders with composite resin were fabricated in each specimen and they were subjected to microshear bond strength (μSBS) testing and analysis of failure pattern. The data were subjected to two-way analysis of variance followed by Tukey and Kruskal-Wallis tests (α = 0.05). No significant differences were observed in the bond strength of the different products without aging. With aging, AU showed higher bond strength values, PH showed a significant reduction in adhesive strength, and HI did not show a significant difference. More cohesive failures were observed in the composite resin of the substrate. It was concluded that pre-hydrolyzed silane exhibits more hydrolytic instability than immediate hydrolysis silane and the universal adhesive.