The role of etching protocols on bond strength of universal adhesives applied to caries affected dentin: a systematic review and meta-analysis.

Objectives: This systematic review aimed to detect whether acid etching pretreatment would enhance the bond strength of universal adhesives (UAs) to caries-affected dentin before and after aging.

Methodology: Two independent researchers reviewed materials published until August 2024 in five databases (Web of Science, PubMed, SciELO, Scopus, Science Direct, and Cochrane Library). The eligibility criteria contained in vitro studies that assessed the bond strength of UAs to caries-affected dentin using etch-and-rinse and self-etch modes, with or without aging. Statistical meta-analysis was performed using inverse variance method by the Review Manager program (p < 0.05).

Results: In total, 26 studies were included in the quantitative analysis. Studies have mostly focused on mild UAs. The application of acid etching did not impact the bond strength of ultra-mild and mild UAs (p > 0.05). Aging considerably reduced the bond strength of mild UAs in etch-and-rinse or self-etch modes (p < 0.05). Bond strength to caries-affected dentin was considerably lower than that to sound dentin in both etching modes (p < 0.05).

Conclusions: Pretreatment with phosphoric acid did not affect the bond strength of mild and ultra-mild UAs to caries-affected dentin. The aging process led to a decrease in the bond strength of mild UAs to caries-affected dentin, irrespective of the application strategy.