Impact of active vs. passive application of dental adhesives on bond strength to dentin and enamel: A systematic review and meta-analysis of in vitro studies.

The application method of adhesive systems affects both immediate and long-term bond strength. This systematic review analyzed in vitro studies comparing active versus passive application of adhesives on enamel and dentin, regardless of classification. A comprehensive search was conducted in PubMed/Medline, Embase, Scopus, Web of Science, Lilacs, and Grey Literature. Included studies assessed bond strength with active or passive application. Meta-analyses were stratified by substrate (enamel and dentin) and application mode (etch-and-rinse or self-etching), using a random-effects model and I² index for heterogeneity. The RobDEMAT tool assessed the risk of bias. Out of 3022 articles, 23 met the inclusion criteria. Meta-analysis showed that passive application of universal adhesives in etch-and-rinse mode resulted in higher bond strength to enamel. However, active application of etch-and-rinse or universal adhesives in etch-and-rinse mode improved bond strength on dentin. For self-etching or universal adhesives in self-etching mode, active application enhanced bond strength on both enamel and dentin. Few studies assessed longevity, but those that did reported positive outcomes for active application. One self-curing universal adhesive showed significantly different results. In conclusion, active application improves bond strength to dentin in two-step etch-and-rinse mode and to unconditioned enamel and dentin in self-etching mode.