Effect of 3-year water storage on the performance of one-step self-etch adhesives applied actively on dentine

Objectives

To evaluate the effect of the application method on the immediate and 3-year resin-dentine bond strength (μTBS) and nanoleakage (NL) for 3 one-step self-etch adhesives (Adper Prompt L-Pop; Clearfil S³ Bond and Xeno III).

Methods

The occlusal enamel of 42 human molars were removed to expose a flat dentine surface. The adhesives were applied under inactive or active application. After light-curing (600 mW/cm² for 10 s), composite buildups were constructed incrementally and sectioned to obtain bonded sticks (0.8 mm²) to be tested in tension immediately or after 3 years of water storage of water storage. For NL, 2 bonded sticks from each tooth at each time were coated with nail varnish, placed in silver nitrate and polished down with SiC paper. The μTBS data was submitted to a two-way repetead mesures ANOVA and Tukey's test for each adhesive (α = 0.05).

Results

The active application showed higher immediate and 3-year μTBS than the inactive application (p < 0.05). An increase in the silver nitrate deposition was seen for all conditions after 3 years; however this was more pronounced for all materials under inactive application (p < 0.05).

Conclusions

The active application improves the immediate bonding performance of the adhesive systems. Reductions of the bond strength were observed for all materials after 3 years, however reduced degradation rate was observed when the materials are applied actively in dentine.