Is Adhesive Bond Strength Similar in Primary and Permanent Teeth? A Systematic Review and Meta-analysis

Purpose: To systematically review the literature on laboratory studies to determine whether the bond strength of adhesives to primary teeth is similar to that to permanent teeth. Materials and Methods: This systematic review was conducted according to PRISMA and registered in PROSPERO (CRD42014015160). A comprehensive literature search was conducted considering in vitro studies published up to June 2015 in the PubMed/MEDLINE database, with no limit on year of publication. Two reviewers independently selected papers, extracted data and assessed the risk of bias. From 422 eligible studies, 42 were fully analyzed. Thirty-seven studies were ultimately included in the systematic review and meta-analysis. A global comparison was performed with a random-effects model at a significance level of p < 0.05, expressed by the difference of means between the groups. The mean bond strengths and standard deviations were tabulated and statistical analyses were conducted in RevMan 5.1 (The Cochrane Collaboration). Results: There was a significant difference between groups, with permanent teeth presenting higher bond strength than primary teeth (p = 0.0005). When the enamel and dentin substrates were considered separately, dentin presented the same trend (p = 0.002), while for enamel there was no significant difference between the dentitions (p = 0.11). The majority of the studies had a high bias risk. Conclusion: Adhesives have higher bond strengths when applied to permanent than to primary teeth. This difference was also valid when the comparison was made between permanent and primary dentin.