AntimicrobialEffectofZincOxideEugenolMixedwithNanosilveronCommonlyIsolatedBacteriafromthePrimaryRootCanalswithNecroticPulp

 The disinfecting effect of root filling materials used in pulpectomy is imperative for the elimination of residual pathogenic microorganisms from the root canal system. This study aimed to assess the antimicrobial effect of ZOE mixed with different concentrations of nanosilver on bacteria commonly isolated from the primary teeth with necrotic pulp.

 This in vitro study evaluated the antimicrobial effect of ZOE mixed with 0%, 0.5%, 1%, 2%, and 5% concentrations of nanosilver on Enterococcus faecalis (E. faecalis), Streptococcus mutans (S. mutans), and Escherichia coli (E. coli) using the direct contact test. Nanosilver was mixed at different concentrations with ZOE and applied to microplates. Suspensions of standard strains of E. faecalis, S. mutans, and E. coli were prepared and exposed to the mixtures. Brain heart infusion broth was also added. Samples of the culture medium were taken from the wells after1 hour and 1, 2, and 7 days and added to a saline solution to obtain the respective dilutions and cultured on brain heart infusion agar. Finally, the number of colonies was counted. Data were analyzed with two-way and three-way ANOVA using SPSS 22 (α = 0.05).

 The mean colony counts significantly decreased following exposure to different concentrations of nanosilver mixed with ZOE, with significant differences between the groups (p value < 0.05). The mean colony counts significantly decreased over time at all the concentrations (p value < 0.05).

 The results showed that the incorporation of nanosilver by up to 5% to ZOE enhanced its antibacterial activity against E. faecalis, S. mutans, and E. coli. Moreover, the mixtures retained their antibacterial property over time.