Antimicrobial abilities of various dentine bonding agents and restorative materials

Objectives: The purpose of this study was to observe and measure the in vitro effect of various composite restorative materials and dentine bonding agents on the growth and adherence of oral bacteria believed to be responsible for recurrent caries in humans and on micro-organisms commonly used to evaluate the effectiveness of disinfecting agents. Methods: Five sets of dentine bonding agents and composite resins and ten species of micro-organisms were used. Circular disc specimens of each composite set were placed onto inoculated plates. Zones of growth inhibition around specimens were measured after incubation. On other plates, specimens were placed alone for 48 h, removed, and then the micro-organisms added. Also, the composite sets were placed into sterilized bovine incisors and suspended into sucrose-containing broth inoculated with Streptococcus mutans for 3 days. Adhering materials were disclosed and scored. Results and conclusions: Four of the composites sets produced statistically similar (P > 0.05) inhibitory zones. The Gram-negative rods and the Staphylococcus aureus were the most resistant micro-organisms. The five composites sets produced the same (P > 0.05) reduction in bacterial accumulation (> 60%). Aging of the specimens in water for periods up to 4 weeks prior to exposure to S. mutons did not affect product activity.