Self-etch Approach of Universal Adhesives as an Alternative to Minimize Bond Degradation on Sound Dentin vs Caries-affected Dentin over Time

Purpose: To investigate the influence of the etching strategy of universal adhesives on bond degradation to sound and artificially-induced caries-affected dentin. Materials and Methods: The universal adhesives (Scotchbond Universal Adhesive; All-Bond Universal; Prime&Bond Elect) and adhesives used as controls (Adper Single Bond 2 and Clearfil SE Bond) were applied to sound and artificially-induced caries-affected bovine dentin. Microtensile bond strength was evaluated immediately (24 h) and after one year of water storage (1 year). Representative specimens were also prepared to assess nanoleakage. Bond strength data (MPa) were analyzed using three-way ANOVA and post-hoc Tukey's test (alpha = 0.05), considering each substrate separately. Results: Bonding degradation was observed for all universal adhesives on caries-affected dentin, irrespective of the etching strategy. On sound dentin, bonding degradation was observed when adhesives were used on the etch-and-rinse strategy. Conclusion: The universal adhesives were not capable of maintaining bond stability over time on caries-affected dentin. The self-etch strategy seems better able to maintain the durability of adhesive interfaces created on sound dentin.