Is the repair bond strength affected when substrate and repair composite are not of the same kind? A systematic review and meta-analysis: Effect of repair composite on repair bond strength

The aim was to evaluate the influence of repair resin type on repair bond strength in the direct resin restorations through a systematic review. Electronic databases MEDLINE via PubMed, Web of Science, Scopus, BBO, and LILACS were searched, and the reference lists of relevant studies were further hand-searched. A total of 15,709 articles that were browsed yielding to a final of five studies were included in meta-analysis. Analyses were performed using R software with the 'metafor' package, with standardized mean differences employed. A multi-level meta-analysis was conducted utilizing restricted maximum-likelihood estimates (p <= .05). In the shear bond strength group, significant heterogeneity was observed (Q = 50.274, p < .0001), whereas no significant heterogeneity was detected in the microtensile bond strength group (Q = 5.102, p = .4063). Separate analyses of both shear bond strength and microtensile bond strength groups showed no statistically significant differences between dissimilar and similar materials (p > .05). Egger's regression indicated no evidence of publication bias in either group. Sensitivity analyses revealed statistically insignificant pooled effect sizes for shear bond strength. In the microtensile group, one study influenced the results when excluded from the analysis. It could be suggested that the repair of composite resin with the same kind of resin composite is not mandatory.