Is prior conditioning of dentin necessary in restoration with glass-ionomer cement? A systematic review and network meta-analysis

Abstract Objective To evaluate the influence of previous conditioning with different materials on the bond strength in dentin, or clinical performance of restorations with glass-ionomer cements (GICs). Methodology: Articles published until February 04, 2020 were searched for in the PubMed and Scopus databases. Gray literature was fetched through the OpenGray platform. The references of the included articles were checked manually. Eligibility criteria (1) be about GICs; (2) test surface conditioning for GICs; (3) be about dentin; and (4) be an intervention study (clinical or laboratorial). Two reviewers participated in the entire process, independently, using structured tables in Excel spreadsheets. Direct and network meta-analyses were performed through mixed treatment comparisons (MTCs) to verify the best conditioning treatment, besides the evaluation of methodological quality and risk of bias. Results 2791 articles were pre-nominated and after the eligibility criteria were applied, 30 articles were selected to perform this study. One clinical study and all in vitro studies presented a high risk of bias. Regarding direct comparisons, in restorations with self-cure GIC, the only possible comparison was between polyacrylic acid and non-previous dentin conditioning, and there was no difference between them. Regarding the use of resin-modified GIC, in the direct comparison between non-previous conditioning and use of polyacrylic acid, a favorable difference toward the use of polyacrylic acid was found. In the subgroup of comparison between non-previous treatment and primer, a favorable difference toward the use of primer was found. In the comparison subgroups between phosphoric acid and non-treatment, cavities conditioners and non-treatment, and phosphoric acid and polyacrylic acid, no statistically significant differences were verified. In the network analysis, considering direct and indirect meta-analyses for resin-modified GICs, it was found that the best conditioning for dentin prior to resin-modified GIC fillings is with phosphoric acid, followed by the cavity conditioners; and the worst is not to perform any type of conditioning. Conclusion Prior conditioning does not interfere with the bond strength of self-cure GICs to the sound dentin of permanent teeth, while conditioning dentin with phosphoric acid improves the bond strength of resin-modified GICs to the sound dentin after 24 h, used in permanent teeth. However, the risk of bias is high, the level of evidence is moderate, and the degree of recommendation is weak.