Effect of refrigeration on bond strength of self-etching adhesive systems

The purpose of this study was to investigate the tensile bond strength to dentin of three self-etching adhesive systems at refrigerated and room temperatures. Seventy-eight bovine incisors were embedded in self-cured acrylic resin, abraded on a water-cooled lathe and polished with 400- and 600-grit sandpapers to obtain standard dentin surfaces. The specimens were randomly assigned to 6 groups (n=13). Clearfil SE Bond, AdheSE and One-Up Bond F adhesive systems at refrigerated (4 degrees C) and room temperatures (23 degrees C) were applied to dentin according to the manufacturers' instructions. A truncated composite resin (Herculite XRV) cone was bonded to dentin surface. The specimens were stored in distilled water at 37 degrees C for 24 h and submitted to tensile bond strength testing at a crosshead speed of 0.5 mm/min. Means in MPa were analyzed statistically by Student's t-test at 5% significance level. No statistically significant differences (p>0.05) were found between the adhesive systems applied at refrigerated and room temperatures. In conclusion, no adverse effects on tensile bond strength were observed when self-etching adhesive systems were used after being taken directly from the refrigerated storage.