Purpose: In an intra-individual comparison, a 6-month randomized, controlled prospective study evaluated the clinical performance of a self-etching and an etch-and-rinse adhesive in noncarious cervical lesions applied as recommended and after doubling the number of adhesive coats. Materials and Methods: Twenty-nine patients with at least two pairs of similar sized noncarious cervical lesions participated. One hundred sixteen restorations were placed and divided into the following groups: OS2: phosphoric acid + One Step Plus applied according to manufacturers recommendation (2 coats of adhesive); OS4: phosphoric acid + One Step Plus (4 coats of adhesive); TY2: Tyrian SPE + One Step Plus applied according to manufacturers recommendation (2 coats of adhesive); TY4: Tyrian SPE + One Step Plus (4 coats of adhesive). The restorations were evaluated at baseline and after 6 months according to the modified USPHS criteria. Statistical analysis was performed with Friedman repeated measures ANOVA by rank and the Wilcoxon sign-ranked test for pairwise significance (α = 0.05). Results: One hundred eight restorations were evaluated at 6 months. The retention rate of the group TY2 was statistically significantly lower than the other groups. Marginal discoloration occurred in all groups, being significantly worst in the group TY2. Conclusion: Tyrian SPE + One Step Plus applied according to manufacturers recommendations did not meet the ADA provisional acceptance criteria for enamel-dentin bonded restorative materials. The use of four coats of the One Step Plus in the self-etching approach can improve its clinical performance.
Keywords: clinical trial, resin composite, adhesives systems, etch-and-rinse adhesive, self-etching adhesive, adhesive application