The effect of zoledronate-containing primer on dentin bonding of a universal adhesive

Abstract

Objectives. To evaluate the bonding ability and nanoleakage of an universal adhesive applied to dentin after zoledronate-containing primer (zol-primer) before and after mechanical load cycling. Materials and Methods. Flat superficial dentin surfaces were exposed on human molars and ascribed to one of the following adhesion procedures (n=6): 1-Adper Single Bond Universal (SBU) applied in etch-and-rinse mode, 2- SBU applied as etch-and-rinse after the application of zol-primer, 3- SBU applied in self-etch strategy, and 4- SBU applied as self-etch after the use of zol-primer. Half of bonded teeth were processed for microtensile bond strength test after 24h and further were cut and surveyed after 200,000 mechanical cycles. Silver-impregnated specimens were assayed for interface nanoleakage by SEM. Data were analyzed by two-way ANOVA and Tukey’s test (p<0.05). Results. At immediate evaluation, the four presented similar bond strengths, whilst both groups bonded with etch-and-rinse technique had significant bond strength reduction after mechanical load (p<0.05), with higher drop for zol-primer group. No negative effects were found for self-etch strategy (p>0.05) in microtensile test. Lower nanoleakage was observed for etch-and-rinse specimens treated with zol-primer. However, noteworthy reduction of adhesive layer thickness was observed with the combination of zol-primer and self-etch strategy. Conclusion. It can be concluded that zol-primer should not be used along with an universal adhesive in etch-and-rinse mode, but its application before self-etch application provides minor alterations.