Effect of airborne-particle abrasion on dentin with experimental niobophosphate bioactive glass on the microtensile bond strength of resin cements.

PURPOSE: The objective of this study was to evaluate the microtensile bond strength (muTBS) of two resin cements bonded to dentin pre-treated with experimental niobophosphate bioactive glass (NBG). METHODS: The experimental bioactive glass was prepared by mixing different amounts of NbO5; (NH4)2HP4; CaO; Na2CO3. The particle size distribution and composition of the bioactive glass powder were determined. Twenty flat dentin surfaces from sound extracted human molars were polished with 600-grit SiC paper and air-abraded using experimental bioactive glass niobium powder. The bonding procedures were accomplished by the application of two resin cements: self-etching Panavia F or self-adhesive RelyX U-100. The resin-bonded specimens were cut and the muTBS test was performed after 24h. The failure mode was determined with a stereomicroscope at 40x magnification. The results were statistically analyzed by two-way ANOVA and Tukey tests (alpha=0.05). RESULTS: The two-way ANOVA did not detect interactions between factors, but only a difference between the self-etching and self-adhesive cement (p=0.001). The self-etching resin cement Panavia F obtained a higher muTBS than the self-adhesive cement Relyx U-100. The predominant failure mode of the cements was adhesive/mixed between the resin cement and dentin. CONCLUSION: A new bioactive glass containing niobium did not interfere with the immediate bonding performance of self-etching and self-adhesive cements.