Effect of six-month water storage on microtensile bond strength of etch and rinse and self-etch adhesive systems to dentin

ABSTRACT

Despite the durable enamel bonding, durability of dentin bonding is under question. However, some self-etch adhesives have been reported to perform as good as etch and rinse adhesive and can resist more against degradative mechanisms. To evaluate the dentin bond strength durability using etch and rinse and self-etch approaches over 1 day and 6 months water storage. This was an experimental study conducted at Shahed Dental School [Tehran, Iran] in 2010. A total of 32 extracted human third molar were sectioned to expose the superficial dentin and randomly distributed into four groups as three-step etch and rinse adhesive [SBMP], two-step etch and rinse adhesive [SB], two-step self-etch adhesive [CSEB], and one-step self-etch adhesive [ABSE]. A resin composite crown was incrementally built up. Microtensile specimens were fabricated and stored in distilled water containing 0.5% chloramine T and the tensile tested after 1 day and 6 months. The failure patterns of debonded specimens were recorded using stereomicroscopy. Oneway ANOVA and Tamhan statistical tests were applied. The SB group attain ed the highest bond strength, in 1 day [27.42 +/- 3.67 Mpa] and 6 months [27.28 +/- 3.25 Mpa]. The short-term bond strength of SBMP and CSEB groups were similar [P>0.05]. A significant decrease in bond strength was observed for both ABSE and SBMP groups [P<0.05]. No reduction in bond strength of SB and CSEB groups was found after 6 months. The ABSE group attained the lowest bond strength compared to other groups [1 day 11.77 +/- 2.81 Mpa, 6 months 9.33 +/- 1.71Mpa]. The failure pattern of SBMP and ABSE groups was adhesive which increased over 6 months. The most frequent pattern of SB and CSEB groups was adhesive which was stable over time. Based on findings of the present study, the resistance of resin-dentin bonds to degradation is material-dependent. The mild two-step self-etch adhesive [CSEB] demonstrates similar short-term performance with SBMP, and remains stable against degradative mechanisms