Antibacterial activities of inorganic agents on six bacteria associated with oral infections by two susceptibility tests

The antibacterial effects of six inorganic antibacterial agents were assessed using broth dilution and agar dilution tests on six pathogenic bacteria associated with oral infectious diseases: Streptococcus mutans (ATCC 25175), S. mutans (Ingbritt), Actinomyces viscosus (ATCC 15987), Lactobacillus casei (ATCC 393), Staphylococcus aureus (ATCC 29213) and Candida albicans (ATCC 90028). The results of the broth dilution test were significantly lower than those of the agar dilution test (F = 38.290; P < 0.01). The six inorganic agents notably inhibited the growth of tested common oral bacteria in vitro. Among them, Longbei inorganic antibiotic powder was the strongest antibacterial agent, followed by ZnO whisker antibacterial complex (ZnOw) AT-83, IONPURE-H, basic magnesium hypochlorite, ZnOw AT-88 and Antim-AMS2. The broth dilution test appears to be more suitable for testing insoluble inorganic agents.