Adhesive systems for restoring primary teeth: a systematic review and meta-analysis of in vitro studies

Aim. To systematically review the literature for in vitro studies that evaluated the immediate or after ageing bond strength of etch-and-rinse and self-etch adhesive systems to enamel and dentin of primary teeth. Design. The search was conducted in PubMed/MEDLINE, Cochrane, SciELO, Lilacs, and Scopus databases with no publication year or language limits, following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement. From 459 potentially eligible studies, 39 were selected for full-text analysis, and 5 were identified in reference lists, with 36 considered in the meta-analysis. Two reviewers independently selected the studies, extracted the data, and assessed the risk of bias. Pooling bond strength data was calculated using random effects analysis method, comparing two categories of adhesives (etch-and-rinse versus self-etch systems) when applied in different types and conditions of substrate (alpha = 0.05). Results. No statistical significant difference in bond strength between both categories was observed in caries-affected dentin at immediate evaluation and in sound dentin after ageing. Etch-and-rinse adhesives, however, performed better in sound enamel and dentin substrates considering immediate bond strength. None study assessed the long-term adhesive effectiveness to sound or demineralized enamel. Conclusion. Although the articles included in this meta-analysis showed high heterogeneity and high risk of bias, the in vitro literature suggests superior performance of etch-and-rinse adhesives in primary teeth in comparison with self-etch systems.