Inhibitory effect of antibacterial resin composite against Streptococcus mutans

Dental resin composites with antibacterial activity may be useful for preventing the secondary caries frequently seen around restorations. Three types of silver-supported antibacterial materials (Novaron, Amenitop and AIS) inhibited the growth of the major oral pathogen Streptococcus mutans. Minimum inhibitory amounts in suspensions of Novaron, Amenitop and AIS against S. mutans were 40, 30 and 400 microg/ml, respectively. These antibacterial materials were incorporated into TEGDMA-UDMA-based light-activated resin composite, and the antibacterial activities of these composites were examined. Composites incorporating 5 wt% (N-5) or more of Novaron and 7 wt% (AM-7) or more of Amenitop inhibited the growth of S. mutans, whereas composites incorporating up to 10 wt% of AIS did not. No significant difference in either compressive or flexural strength was observed between the control and N-5 composites after 1 day and 6 months of storage in water. However, for AM-5 composite, there was a significant difference in either strength parameter between the two immersion periods. There was no or extremely little release of silver ions from the N-5 and AM-5 composites after 1 day or 6 months of immersion in water. These results indicated that a light-activated resin composite incorporating silver-supported antibacterial material such as Novaron may be clinically useful due to its inhibitory effect against S. mutans and favorable mechanical properties.