Antibacterial Activity of Calcium Hydroxide and Zinc Oxide Combined with Several Solutions against Enterococcus faecalis Growth

Objective This study aims to compare the antimicrobial activity of calcium hydroxide (CaOH) and zinc oxide (ZnO) when incorporated with other solutions such as 2% chlorhexidine (CHX), 2.5% sodium hypochlorite (NaOCl), 1% povidone-iodine (PVP-I), and sterilized distilled water (ddH2O) against Enterococcus faecalis.
Materials and Methods The materials were prepared by mixing CaOH and ZnO with other solutions (CHX, PVP-I, NaOCl, and ddH2O) separately. The antibacterial activity of CaOH and ZnO mixtures against E. faecalis was done by using disk diffusion assay (DDA). Twofold serial dilutions of the mixtures were used against E. faecalis to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. Biofilm inhibition of E. faecalis had been measured by using crystal violet assay. Statistical Analysis The quantitative data of this study had been analyzed by using two-way analysis of variance with software SPSS version 27. The result is considered as significant if the value of analysis is p-value less than 0.05. Results From the DDA results, the lowest zone of inhibition toward E. faecalis was CaOH-PVP-I (6.00 0.00 mm), while the highest zone of inhibition toward E. faecalis was CaOH-CHX (22.73 0.02 mm). Besides that, ZnO-PVP-I showed the lowest zone of inhibition (16.50 0.06 mm), while ZnO-CHX showed the highest zone of inhibition
(18.30 0.08 mm) against E. faecalis. The MIC and MBC values of CaOH-CHX and ZnOCHX were 0.78 and 6.25 mg/mL, respectively. In biofilm assay, CaOH-CHX and ZnOCHX were reduced biofilm formation of E. Faecalis. Conclusion Both CaOH-CHX and ZnO-CHX showed the highest antimicrobial activities toward E. faecalis. CaOH and ZnO alone showed no antimicrobial activities against E. faecalis.