Resin composite materials exhibit good esthetic properties and strength, making them the most commonly used materials for restoring hard tissue, i.e., enamel and dentin. In the last 30 years these restorative materials have been widely used for both anterior and posterior restorations. Regrettably, studies have indicated numerous failures, the main reason for which is secondary caries. Resin composites were found to accumulate more dental plaque than enamel and other restorations. Thus, to increase the service life of resin composite restorations, modifications introducing antibacterial properties are required. In this review the authors discuss the advantages and disadvantages of various released and non-released antibacterial agents incorporated in resin composites. A change in strategy based on the use of antimicrobial polymeric macromolecules is suggested, focusing on polycationic antimicrobials. Polyethyleneimine nanoparticles, in particular, are presented as a possible solution to the disadvantages of released antiseptic agents. Developing agents with strong antimicrobial activity upon contact that do not diminish over time nor affect the biocompatibility of materials should be the focus of future research. (C) 2013 Elsevier Ltd. All rights reserved.