Effect of an ethanol cross-linker on universal adhesive.

OBJECTIVE: To evaluate the effects of N,N'-dicyclohexylcarbodiimide (DCC), an ethanol-based dentin cross-linker, on the immediate and long-term microtensile bond strength (muTBS) and nanoleakage expression of a universal adhesive employed in self-etch mode (SE) or etch-and-rinse mode (ER). The effect of DCC on the dentinal MMP activity was also investigated by means of in-situ zymography. METHODS: Eighty freshly extracted human molars were sectioned to expose mid-coronal dentin surfaces. The teeth were assigned to one of the following groups, according to the dentin surface priming/adhesive approach: (G1): DCC pre-treatment and Scotchbond Universal (SBU) in ER mode; (G2): SBU in ER mode; (G3): DCC pretreatment and SBU in SE mode; (G4): SBU in SE mode. muTBS test was performed immediately (T(0)) or after 1-year aging (T(12)) in artificial saliva. Ten additional teeth per group were prepared for nanoleakage evaluation (N = 5) and for in-situ zymography (N = 5). RESULTS: Three-factor analysis of variance revealed significant difference for the variables DCC pretreatment, application mode and aging (p < 0.05) for both microtensile bond strength testing and in-situ zymography. Nanoleakage analysis revealed reduced marginal infiltration of DCC experimental groups both at T(0) and T(12). SIGNIFICANCE: The use of an ethanol-based primer containing DCC appears to be promising in preserving the stability of the adhesive interface of a universal adhesive, especially in the SE mode.