Antibacterial properties of resin composites and dentin bonding systems

This paper reviews the research conducted on the evaluation of antibacterial properties of commercial composites and adhesive systems, in addition to the discussion on many attempts to achieve antibacterial composites or adhesives. With regard to composites, commercially available products including fluoride-releasing materials have no antibacterial effect after being cured, which may explain why composites accumulate more plaque than other filling materials. The attempts to provide composites with antibacterial properties involve alterations to the resin components and filler components, and the trials can be subsequently classified into two groups based on the release profile of antibacterial components; agent-releasing or non-agent-releasing materials. Each type of antibacterial composite has advantages and disadvantages, and further modifications are needed to achieve clinically useful materials. Among proprietary dentin bonding systems (DBS), the products which contain glutaraldehyde or have an acidic property exhibit some antibacterial effects. However, the antibacterial properties shown by these products are only side-effects which are derived from the constituents included to produce superior bonding characteristics, and appear to be unreliable. Inclusion of antibacterial components into DBS has also been attempted using several methods, and the results of in vitro tests indicate that some of the trials seem promising. It is worthy of continuing the attempts to develop DBS which can inhibit invading bacteria after the placement of restoration as well as residual bacteria in the cavity. Achievement of bio-functional composites or DBS with therapeutic effects would contribute to prevent secondary caries.