ANTIBACTERIAL ACTIVITY OF SILVER IONS IMPLANTED IN SIO2 FILLER ON ORAL STREPTOCOCCI

Objective. To evaluate the role of silver ions in composite resin dent al materials, an in vitro investigation was conducted into the antibac terial effect of SiO2 filler implanted with silver ions on oral strept ococci. Methods. SiO2 filler samples (0.1g) were implanted with silver ions. The effect of the filler with silver ions (Ag+ filler) was test ed on oral streptococci bacteria. These bacterial strains had been iso lated predominantly from composite resin surfaces. The organisms teste d were anaerobically cultured in 5 mL Trypticase Soy Broth containing 0.5 per cent yeast extract at 37 degrees C for 10 - 12 h. Each bacteri al strain was adjusted to a concentration of 1 x 10(6) cells per mL wi th reduced transport fluid (RTF). Ag+ filler was immersed in 1 mL of R TF and anaerobically incubated 2, 6 and 12 h to study the antibacteria l effect. survival of bacteria was then estimated by culturing on TSBY agar plates. A plate with approximately discrete colonies was chosen from the serial agar cultures, and the number of colonies was counted at each sampling time. Results. The Ag+ filler showed significantly mo re antibacterial activity than the control filler without silver ions. Significance: These results indicate that the antibacterial effect fo und in this study was due to the silver ions released by the Ag+ fille r and that it may be useful to add this filler to composite resin dent al materials for secondary caries protection.