Effect of moisture and drying time on the bond strength of the one-step self-etching adhesive system

OBJECTIVES To investigate the effect of dentin moisture degree and air-drying time on dentin-bond strength of two different one-step self-etching adhesive systems. MATERIALS AND METHODS Twenty-four human third molars were used for microtensile bond strength testing of G-Bond and Clearfil S(3) Bond. The dentin surface was either blot-dried or air-dried before applying these adhesive agents. After application of the adhesive agent, three different air drying times were evaluated: 1, 5, and 10 sec. Composite resin was build up to 4 mm thickness and light cured for 40 sec with 2 separate layers. Then the tooth was sectioned and trimmed to measure the microtensile bond strength using a universal testing machine. The measured bond strengths were analyzed with three-way ANOVA and regression analysis was done (p = 0.05). RESULTS All three factors, materials, dentin wetness and air drying time, showed significant effect on the microtensile bond strength. Clearfil S(3) Bond, dry dentin surface and 10 sec air drying time showed higher bond strength. CONCLUSIONS Within the limitation of this experiment, air drying time after the application of the one-step self-etching adhesive agent was the most significant factor affecting the bond strength, followed by the material difference and dentin moisture before applying the adhesive agent.