Effect of warm-air stream for solvent evaporation on bond strength of adhesive systems: A systematic review and meta-analysis of in vitro studies

Abstract Purpose To determine whether warm-air stream for solvent evaporation improves immediate and long-term bond strength of adhesive systems through a systematic review and meta-analysis. Materials and methods PubMed, ISI Web of Science, Cochrane Library, SciELO, Scopus, and BVS, as well as Open Grey, were searched for relevant studies. Only in vitro studies reporting the effect of the use of warm-air stream to evaporate solvents of adhesive systems on the bond strength to enamel or dentin, were included. A global analysis compared the standardized mean difference between bond strength values using warm-air stream against a control group in which room-temperature air-stream was used. Bond strength from etch-and-rinse and self-etch adhesives was analyzed separately using the random-effects model at a significance level of α = 0.05. For each adhesive type, subgroup analyses were performed considering the type of solvent with which the adhesives were formulated. Results A total of 10 in vitro studies were included in the meta-analysis. For etch-and-rinse or self-etch adhesives, the use of warm-air stream for adhesive solvent evaporation improved the bond strength to dentin of water- or alcohol-based adhesive systems (p ≤ 0.03). On the contrary, this effect could not be observed for acetone-based adhesive systems (p ≥ 0.13). The overall effect demonstrated bond strength was enhanced with the use of warm-air stream (p ≤ 0.03). Conclusion The in vitro evidence suggests that bond strength of self-etch or etch-and-rinse adhesives could be improved by using warm-air stream for solvent evaporation.