Bond strength of two resin cements on dentin using different cementation strategies

PURPOSE: This study evaluated the microtensile bond strength of two resin cements to dentin either with their corresponding self-etching adhesives or employing the three-step "etch-and-rinse" technique. The null hypothesis was that the "etch-and-rinse" adhesive system would generate higher bond strengths than the self-etching adhesives. MATERIALS AND METHODS: Thirty-two human molars were randomly divided into four groups (N = 32, n = 8/per group): G1) ED Primer self-etching adhesive + Panavia F; G2) All-Bond 2 "etch-and-rinse" adhesive + Panavia F; G3) Multilink primer A/B self-etching adhesive + Multilink resin cement; G4) All-Bond 2 + Multilink. After cementation of composite resin blocks (5 x 5 x 4 mm), the specimens were stored in water (37 degrees C, 24 hours), and sectioned to obtain beams (+/-1 mm(2) of adhesive area) to be submitted to microtensile test. The data were analyzed using 2-way analysis of variance and Tukey's test (alpha = 0.05). RESULTS: Although the cement type did not significantly affect the results (p = 0.35), a significant effect of the adhesive system (p = 0.0001) was found on the bond strength results. Interaction terms were not significant (p = 0.88751). The "etch-and-rinse" adhesive provided significantly higher bond strength values (MPa) with both resin cements (G2: 34.4 +/- 10.6; G4: 33.0 +/- 8.9) compared to the self-etching adhesive systems (G1: 19.8 +/- 6.6; G3: 17.8 +/- 7.2) (p < 0.0001). Pretest failures were more frequent in the groups where self-etching systems were used. CONCLUSION: Although the cement type did not affect the results, there was a significant effect of changing the bonding strategy. The use of the three-step "etch-and-rinse" adhesive resulted in significantly higher bond strength for both resin cements on dentin. CLINICAL SIGNIFICANCE: Dual polymerized resin cements tested could deliver higher bond strength to dentin in combination with "etch-and-rinse" adhesive systems as opposed to their use in combination with self-etching adhesives