Effect of repeated use on dentin bond strength of two adhesive systems: All-in-one and one-bottle

Abstract

To compare the effects of repeated use of two one-bottle adhesives with that of two all- in- one adhesives (with acetone solvent) on bond strength to dentin. A flat dentin surface was prepared on 120 bovine incisors using 600- grit abrasive pape. The teeth were randomly assigned into 12 equal groups. The four adhesive systems [Prime and Bond NT (P&B NT), One-Step Plus (OS), iBond (iB), and G-Bond (GB)] were used at baseline, after the lid of the container had been opened 30 times, and after it had been opened 60 times. Before each use of the adhesives, the lids of the containers were left open for 1 min. The resin composites were applied on the dentin in a cylindrical split mold. After thermocycling, shear bond strength test was performed with a universal testing machine at 1 mm/min. We used Kruskal-Wallis and Dunn tests for statistical analysis. There was no statistically significant difference among bond strength (MPa) of the groups of P&B NT (31.9 +/- 4.6, 31.8 +/- 6.5, 26.1 +/- 6.7) and OS (33.2 +/- 5.1, 30.9 +/- 7, 29.3 +/- 5.9), respectively (P > 0.05). The mean of the bond strength of iB and GB after 60 times (15.3 +/- 4.1 and 12.2 +/- 3.9, respectively) was significantly lower than that of iB and GB at baseline (23.5 +/- 4.8 and 22.2 +/- 4.5, respectively) (P < 0.05). Repeated use (60 times) of the all-in-one adhesive led to a decline in the dentin bond strength. To avoid this problem it would be advisable to have containers with smaller amounts of adhesive or perhaps those with only a singe dose.