Data sourcesMedline, Scopus, Web of Science, Latin American and Caribbean Health Sciences Literature database (LILACS), Brazilian Library in Dentistry (BBO), Cochrane Library, System for Information on Grey literature in Europe (SIGLE), ProQuest Dissertations and Theses, Periódicos Capes Theses database, Current Controlled Trials (www.controlled-trials.com), International Clinical trials registry platform (http://apps.who.int/trialsearch/), the ClinicalTrials.gov (www.clinicaltrials.gov), Rebec (www.rebec.gov.br) and EU Clinical Trials Register (https://www.clinicaltrialsregister.eu), abstracts of the annual conference of the International Association for Dental Research (IADR) and their regional divisions.Study selectionTwo reviewers selected studies; parallel or split-mouth randomised controlled trials (RCTs) comparing adhesive strategies were considered.Data extraction and synthesisData were abstracted by two reviewers and into four follow up periods, 1 year; 18 months to 2 years; 3 years and 4 to 5 years. The Cochrane risk of bias tool was used to assess study quality. Data outcomes were dichotomous and summarised using relative risks and random effects meta-analysis.ResultsTwenty-nine studies were included in the meta-analysis. Bonding strategy did not influence postoperative sensitivity (risk ratio [RR] 1.04; 95% CI 0.81 to 1.34) or retention rates (RR = 1.04; 95% CI 0.81 to 1.34). The etch-and-rinse approach produced less marginal discoloration at 18 months to 2 years (RR 1.51; 95% CI 1.21 to 1.90) and at 4 to 5 years (RR 1.81; 95% CI 1.28 to 2.55) (p<0.0007).ConclusionsComposite resin restorations placed with self-etch and etch-and-rinse adhesives produce restoration with similar clinical service and POS, however using etch-and-rinse adhesives one can reduce marginal discoloration.