OBJECTIVETo evaluate effects of incorporating tetrapod-like zinc oxide whisker (T-ZnOw) antibacterial agent on the antibacterial activity of composite resin, compared with that of the silver-based inorganic antibacterial agent.

METHODSThe minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the two different antibacterial agents against Streptococcus mutans were investigated using the broth dilution test. Then the antibacterial activities of the self-cured composite resin specimens with different incorporating concentrations of the two antibacterial agents were evaluated using direct contact test. And the antibacterial activities of the resin specimens were examined again after 3 months of accelerating aging.

RESULTSThe MIC (MBC) of the T-ZnOw antibacterial agent and silver-based inorganic antibacterial agent were 0.15625 (0.3125) g/L and 0.15625 (0.15625) g/L. When the concentrations of T-ZnOw added to composite resin were 3%, 5%, and 10% (w/w), the antibacterial ratios of the resin specimens were (84.85+/-5.16)%, (94.22+/-3.73)%, and (99.43+/-0.48)% respectively. When the concentrations of the silver-based antibacterial agent added to composite resin were 1%, 3%, and 5%, the antibacterial ratios were (71.01+/-7.67)%, (90.76+/-5.91)%, and (97.19+/-4.10)% respectively. The antibacterial ratios of the resin specimens containing 5% of both antibacterial agents were (89.89+/-5.55)% and (78.79+/-7.81)% respectively after 3 months of accelerating aging.

CONCLUSIONSIncorporation of the T-ZnOw antibacterial agent in composite resin can improve the antibacterial performance of the resin, and the resin exhibits better antibacterial performance than that incorporating silver-based inorganic antibacterial agent after 3 months of aging.