Bonding agent underneath sealant: bond strength to laser irradiated enamel

Objectives: This study evaluated in vitro the shear bond strength (SBS) of a resin-based pit-and-fissure sealant [Fluroshield (F), Dentsply/Caulk] associated with either an etch-and-rinse [Adper Single Bond 2 (SB), 3M/ESPE] or a self-etching adhesive system [Adper SE Plus (SE), 3M/ESPE] to Er:YAG laser irradiated enamel. Methods: Thirty three sound third molars crowns were embedded in acrylic resin and enamel surfaces were flattened. The enamel sites were irradiated with a 2.94-ìm wavelength Er:YAG laser (300-mJ, 2-Hz, non-contact mode/17mm, 20s). The specimens were randomly assigned to 3 groups, according to the bonding technique: I- 37% phosphoric acid etching + SB + F; II- SE + F; III- F was applied to acid-etched enamel without an intermediate bonding agent layer. In both groups, a 3-mm diameter enamel bonding site was demarcated and sealant cylinders were bonded. After 24 hours in distilled water, shear bond strength was tested at a crosshead speed of 0.5 mm/minute. Data were analyzed by one-way ANOVA and Tukey's test. The debonded specimens were examined with a stereomicroscope to assess the failure modes. Results: Mean SBS in MPa were: I=6.39 (+/-1.44); II=9.50 (+/-2.79); III=5.26 (+/-1.82). No statistically significant difference (P>.05) was observed between groups I and III, SE/F presented significantly higher SBS than that of the others groups. Conclusion: The application of the self-etching bonding agent (Adper SE Plus) underneath the resin pit-and-fissure sealant placement resulted in significantly higher bond strength to Er:YAG laser irradiated enamel.