Antibacterial activity of zinc oxide nanoparticles in self-curing acrylic resin against Streptococcus mutans. The main objective of this study was to investigate whether nanoparticles of zinc oxide (ZnO) in self-curing acrylic resin, have antimicrobial properties against Streptococcus mutans, one of the microorganisms involved in the development of caries. Self-cured acrylic resin samples were prepared by incorporating ZnO nanoparticles at different concentrations based on the minimum inhibitory concentration (MIC) for Streptococcus mutans ATCC 25175. Antibacterial activity against a biofilm was evaluated in samples that were aged in artificial saliva for different times using spectral confocal laser microscopy and scanning electron microscopy. Kruskal-Wallis test using IBM SPSS Statistics version 23.0 software (SPSS Inc. ®, Chicago, IL, United States) were used, establishing the value of p <0.05 for statistical significance. The volume of the total biomass that formed in the samples aged for one day was significantly lower than the volume of the total biomass that was formed in those aged for additional days (p <0.001). Electron microscopy analysis revealed high porosity surfaces in all samples. Bacterial clusters were located next to large pores and irregular surfaces, while smooth surfaces had defined and linear organization cocci or simple chains. Considering the limitations of this study, the results suggest that the antibacterial activity of ZnO nanoparticles added to self-curing acrylic (ALIKE) is effective, mainly in fresh 1-day samples, independent of their concentration, and in samples with 16 MIC aged for 14 days, indicating it does not lose its antibacterial activity despite setting for more days. In addition, the ZnO nanoparticles added to ALIKE have the ability to inhibit the formation of biofilms, although they do not minimize the number of viable bacteria.
KEY WORDS: Biofilm, Minimum Inhibitory Concentration (MIC). Nanoparticles. Streptococcus mutans. Zinc oxide.
How to cite this article
QUEZADA, M. P.; LUENGO, M. L.; QUEZADA, A. M.; MELENDREZ-CASTRO, M.; BELLO-TOLEDO, H.; GONZÁLEZ-ROCHA, G. & SÁNCHEZ-SANHUEZA, G. Antibacterial activity of zinc oxide nanoparticles in self-curing acrylic resin against Streptococcus mutans. Int. J. Odontostomat., 15(3):694-701, 2021.