Effects of the application protocol and bonding strategy of the universal adhesive on dentin previously impregnated with bioceramic sealer

Purpose

To evaluate the effects of the application of universal adhesive with manual brush (MB) or rotary brush (RB), in the etch-and-rinse (ER) or self-etching (SE) strategy, on the bond strength, adhesive layer thickness, and adhesive failure pattern to dentin impregnated with bioceramic sealer, at 24 h and 1 year.

Materials and methods

Eighty-eight bovine incisor crowns were impregnated with bioceramic sealer was kept for 15 min and cleaned with cotton soaked in distilled water. They were then divided into four groups (n = 22): ER-MB, ER-RB, SE-MB, SE-RB. Subsequently, the specimens were restored with Filtek Z-250 resin. The adhesive layer thickness was individually analyzed using laser confocal microscope. Bond strength was assessed through microtensile testing, and the failure pattern was examined using a stereomicroscope. Data were analyzed by one-way ANOVA/Tukey's tests (α = 0.05).

Results

The adhesive layer thickness provided by ER-MB and SE-MB was greater than that provided by ER-RB and SE-RB (P < 0.05). ER-MB showed the lowest bond strength at 24 h (P < 0.05). At 1 year, SE-MB and SE-RB exhibited the highest bond strength values (P < 0.05). ER-MB demonstrated a higher incidence of adhesive failure at 24 h. At 1 year, SE-RB and SE-MB showed a higher incidence of mixed failure.

Conclusion

The use of Scotchbond Universal® adhesive in the etch-and-rinse strategy applied with a MB negatively affects bond strength at 24 h, worsening after 1 year of control, regardless of the application protocol.