Photochemical crosslinking of caries-affected dentin combined with total- or self-etch systems

Purpose: To evaluate the effects of collagen crosslinking with riboflavin 0.1% and ultraviolet-A (UVA) 5.4 J on bond strength of total-etch or self-etch adhesives on caries-affected dentin. Methods: Sixty human caries-affected molars were randomly divided into three groups: control (C), riboflavin (R), and riboflavin + 3 minutes of UVA (R+UVA). After each treatment, either total-etch or self-etch adhesives were applied following the manufacturer's instructions, and composite stubs were built up on the treated surfaces. They were de-bonded in tension to measure bond strength. Twelve extra molars were used for scanning electron microscope (SEM) analysis. Results: We observed that R+UVA-treated group yielded significantly higher bond strengths for carious dentin when the total-etch adhesive was applied. For the self-etch adhesive, no statistical differences were observed between the three pretreated groups. Conclusion: Our results, for the first time, are suggesting that etching with phosphoric acid potentialized the benefits of R+UVA crosslinking on carious dentin. R+UVA dentinal collagen crosslinking improves bond strength for caries-affected dentin when using a total-etch adhesive, but did not affect it when using a self-etch adhesive.