Comparison of adhesive system bond strength in composite restoration repairs: A systematic review and meta-analysis of in vitro studies

Abstract

Repairing localized failures in restorations can be as durable as complete replacement, offering a more conservative and efficient alternative. However, no "standard" protocol or ideal materials currently exist for this procedure. This systematic review (PROSPERO CRD42022322572) investigated different adhesive systems (Total-etch, Self-etch, and Universal) in repairing direct composite restorations. The review included in vitro studies that evaluated bond strength in composite repairs after surface roughening. A comprehensive literature searches up to April 18, 2022, across six databases (PubMed, Scopus, Web of Science, Embase, LILACS and BDTL), identified 133 relevant studies from an initial 1357, with 15 meeting the inclusion criteria. Fourteen of these studies underwent quantitative analysis and meta-analysis. Quality Assessment Tool for In Vitro Studies was used to evaluate methodological quality. The meta-analysis was performed with R Studio, used the standardized mean difference with a 95 % confidence interval to assess bond strength. The random-effects study heterogeneity using the I-squared statistic. Tensile/microtensile studies found that Total-etch systems were more effective in enhancing bond strength, whereas shear and micro-shear studies favored Self-etch systems. The Universal adhesives showed inconsistent results between the two bond strength tests. Both types of studies, demonstrated that employing an adhesive system enhances bond strength in repairs. The review highlights the need for standardized research to achieve more definitive conclusions.