Does extended air‐drying time improve bond strength of universal adhesives to enamel?

Abstract

AbstractObjectiveTo investigate the effect of extended air‐drying time on the microshear bond strength (MSBS) of universal adhesives to enamel.Materials and MethodsThe distal and mesial specimens from third molars were wet‐ground and randomly assigned to three groups according to adhesives tested (n = 60): Clearfil Bond Universal, Gluma Bond Universal, and G‐Premio Bond. The adhesives were applied in etch‐and‐rinse or self‐etch modes, followed by air‐drying for 5, 15, or 25 s. Composite buildups were constructed and subjected to the MSBS test after 24‐h or thermocycling. MSBS results were evaluated using a four‐way ANOVA. The thickness of the adhesive layer and the degree of solvent evaporation were further evaluated.ResultsAt 24‐h, MSBS of G‐Premio Bond significantly improved with the 25 s air‐drying in both of the etching modes when compared to the 5 s air‐drying. After thermocycling, the extended air‐drying did not produce a significant difference on the MSBS, regardless of the application strategy. Extended air‐drying (25 s) evaporated almost all of the volatile part of Gluma Bond Universal and G‐Premio Bond.ConclusionsExtended air‐drying times increased solvent evaporation but did not contribute to the bonding effectiveness of the adhesives, regardless of the etching mode.Clinical SignificanceAir‐drying applications for more than 5 s had no significant effect on enamel bonding performance of universal adhesives.