Abstract
The purpose of this study was to evaluate the influence of phosphoric acid etching on the enamel and dentinbond strength of single-step and two-step self-etch adhesive systems. The adhesive systems employed wereScotchbond Universal Adhesive, Peak Universal Bond and Clearfil Mega Bond. Bovine teeth were used assubstitute human teeth. The adhesive was applied with and without prior phosphoric acid etching and resin pasteswere inserted into the mold on the tooth surface. After storage in 37ºC distilled water for 24 h, shear bondstrengths were measured at a crosshead speed of 1.0 mm/min. The bonding interface was observed by scanningelectron microscopy (SEM). Though the enamel bond strength was affected by prior phosphoric acid etching,significantly higher enamel bond strengths were obtained with phosphoric acid etching. On the other hand, dentinbond strength decreased with prior phosphoric acid etching. In the SEM observations, tight adaptations wereexhibited in both enamel and dentin specimens. From the results of this in vitro study, additional etching withphosphoric acid to improve bonding effectiveness should be limited to enamel. The effect of using prior phosphoricacid etching with the self-etch adhesive system should be carefully considered in clinical situations.