Antibacterial effect of silver-zeolite on oral bacteria under anaerobic conditions

Objectives: The purpose of this study was to evaluate the antibacterial effect of silver-zeolite (SZ) against oral bacteria under anaerobic conditions. Methods: The antibacterial activity of SZ was evaluated by determining the minimum inhibitory concentrations (MICs) using two-fold serial dilutions of SZ in Brain Heart Infusion broth. Release of Ag+ into the broth was measured by an atomic absorption technique. Results: SZ inhibited the growth of the bacteria tested under anaerobic conditions. The MIC of SZ ranged between 256 and 2048 μg/ml, which corresponded to a range of 4.8–38.4 μg/ml of Ag+. All strains grew in broth containing 16,384 μg/ml of type-A zeolite. Significance: These results suggested that SZ may be a useful vehicle to provide antibacterial activity to dental materials used even under anaerobic conditions such as deep in the periodontal pocket.