RESUMEN
OBJECTIVES: The aim of this study was to systematically review the literature on the clinical behavior of direct anterior composite restorations and to identify the factors potentially influencing restoration success and longevity. MATERIALS AND METHODS: The search included all existing references until September 2016 cited in the PubMed database, the Cochrane central register of controlled trials and Cochrane Library, EMBASE, an internet search using Google internet search engine (possibly including unpublished data), a hand search (University of Geneva library), and the perusal of the references of relevant articles. Studies with appropriate research protocols and that clearly reported data about the performance of anterior composite restorations were included. Yearly failure rates (YFRs) were computed for each study based on survival rates or, when not reported, using United States Public Health Service (USPHS) scores leading to reintervention. The potential impact of the following factors was evaluated: composite filler technology (microfilled, macrofilled, nanofilled or hybrid), polymerization mode (chemical or light cured), treatment environment (academic, private or social) and operator (single or multiple). The studies were analyzed according to the observation time (< 2 years, 2 to 5 years, and > 5 years). RESULTS: 39 potential studies were identified, from which 24 met the review inclusion criteria: nine randomized controlled trials (CTs), two prospective CTs, one retrospective CT, six prospective case series (CSs), and four retrospective CSs. CONCLUSION: This review followed a standard approach and explored an alternative review process that limited the significant data loss that occurs when the meta-analysis method is used. Overall, anterior composite restorations have shown a large heterogeneity in performance, as is typically observed in reviews of clinical studies, but the present appraisal identified influential factors such as treatment environment and the number of operators.