Bonding efficacy of 1-step self-etch adhesives: effect of additional enamel etching and hydrophobic layer application.

Purpose: The purpose of this study was to analyze the effect of additional enamel etching and hydrophobic layer application on microleakage of 1-step self-etch adhesives.

Methods: Class V cavities were made on the buccal surfaces of 80 extracted human premolars. The teeth were divided into 2 test groups according to the 1-step self-etch adhesive used: Clearfil S(3) Bond and Xeno III. Each test group was subdivided into 4 groups (n=10) according to application mode of the adhesive: (1) Group 1=adhesive applied following manufacturer's directions; (2) Group 2=enamel etching prior to adhesive application; (3) Group 3=same as Group 1, plus application of an additional coat of hydrophobic resin layer; (4) Group 4=same as Group 2, plus application of an additional coat of hydrophobic resin layer. The adhesives were light cured, and the cavities were filled with resin composite. Specimens were thermocycled and analyzed for leakage using Kruskal-Wallis and Mann-Whitney U test at a significance level of P=.05.

Results: Enamel etching significantly reduced leakage in both the adhesives. Hydrophobic resin layer application significantly reduced leakage in Xeno III.

Conclusions: An additional acid etching step and hydrophobic resin layer application can improve the bonding of 1-step self-etched adhesives to enamel and dentin, respectively.