The Effect of Deproteinizing Agents on Bond Strength of Resin-based Materials to Enamel: A Systematic Review and Meta-Analysis of In Vitro Studies.

PURPOSE: To systematically review the literature to evaluate whether the bond strength of resin-based materials to enamel is affected by deproteinizing agents. MATERIALS AND METHODS: This systematic review and meta-analysis was conducted according to the PRISMA statement. PubMed, ISI Web of Science, Cochrane Library, SciELO, Scopus, LILACS, IBECS, and BVS databases were screened up to December 2020. Eligibility criteria included in vitro studies that reported the effect of a deproteinizing agent applied before or after acid etching on the immediate or long-term bond strength of resin-based materials to enamel. The meta-analysis was carried out using Review Manager (version 5.3.5). A global comparison was performed with the standardized mean difference based on random-effect models at a significance level of alpha = 0.05. RESULTS: A total of 23 studies were included in the meta-analysis. In all the studies, only the immediate bond strength was evaluated. The bond strength of the materials was improved by the application of NaOCl or papain prior to enamel etching with phosphoric acid (p </= 0.006). None of the deproteinizing agents had a significant effect when applied after etching with phosphoric acid (p >/= 0.27). CONCLUSIONS: Based on in vitro studies, deproteinization with sodium hypochlorite or papain-based agents increases the immediate bond strength of resin-based materials to enamel only when used prior to phosphoric-acid etching.