Repair bond strength of dental composites: systematic review and meta-analysis

This study investigated by means of a systematic review of the literature and meta-analysis the impact of physical and/or chemical surface treatments on the repair bond strength of methacrylate-based dental composites. Three international databases (Medline/PubMed, Scopus, and Web of Science) were searched. Studies that evaluated the repair bond strength of aged control composites (untreated or treated with abrasives) and aged composites subjected to surface treatments before repair (physical, chemical, or physical + chemical) were included. In total, 777 articles were found, 129 were selected for full-text reading, and 15 studies were included in the qualitative and quantitative synthesis. Meta-analyses were conducted using random effects model to calculate pooled mean differences between control and treated composites, according to the different groups of surface treatments. Statistical heterogeneity was assessed using the Cochrane Q statistic and I2 test. Risk of bias of all included studies was assessed. Application of chemical or physical + chemical surface treatments of aged composites was shown to generally improve their repair bond strengths. Silane coupling agents appeared to have a minor role as compared to adhesive agents in improving repair potential. Airborne-particle abrasion alone was found not to contribute significantly to the repair bond strengths. High heterogeneity was observed in most statistical analyses; the analysis of risk of bias also indicated potential problems associated with reporting in the studies. Therefore, suggestions for future in vitro studies on the repair bond strength of dental composites are given.