Efficacy of different adhesive systems in bonding direct resin composite restorations: a systematic review and meta-analysis

ObjectiveThis study aimed to identify and evaluate scholarly research on the efficacy, durability, and long-term stability of various adhesive systems used for bonding direct resin composite restorations and to identify factors influencing bonding performance, such as adhesive composition, application protocol, substrate type, and etching technique.Materials and methodsAn all-inclusive electronic database search for peer-reviewed scholarly journal articles was conducted using PubMed, ScienceDirect, Google Scholar, Dimensions, and the Cochrane Library for research articles investigating the effectiveness of different adhesive systems in direct resin composite restorations, excluding reviews, meta-analyses, opinion pieces, and case reports. The risk of bias was assessed using the Cochrane tool (Robvis 2.0). Data were extracted and thematically analyzed, and quantitative data were statistically analyzed using Review Manager software. Dichotomous data were evaluated using the Mantel-Haenszel method, applying a random effects model and 95% confidence interval.ResultsThe database search yielded 1632 potential articles, of which 14 were included in this study. Several adhesive systems exhibit excellent tensile bond strength. In addition, the type of resin composite, adhesive system, and artificial aging significantly influenced the bonding performance of resin composite restorations. However, the failure rates were low in the different adhesive systems, showing comparable results between the two-step etch-and-rinse and one-step self-etch adhesive systems (p = 0.71). The results showed an overall trend of high bonding effectiveness with a low incidence of adverse events, such as postoperative sensitivity, adhesive failure, and fractures.ConclusionThe study results emphasize the importance of selecting appropriate adhesive systems based on clinical case requirements, restoration characteristics, and patient factors to enhance bonding efficacy, durability, and long-term stability.