Inhibitory activity of root canal irrigants against Candida albicans, Enterococcus faecalis and Staphylococcus aureus

Abstract

The present study evaluated the antimicrobial activity of three root canal irrigants against Enterococcus faecalis, Candida albicans, and Staphylococcus aureus. These microorganisms were incubated in the presence of citric acid (6 and 10%), EDTA (17%), and NaOCl (0.5, 1.0, 2.5, and 5.25%). Agar diffusion tests were performed and redox indicator resazurin was used to evaluate the inhibitory effect of the irrigants on the metabolic activity of these microorganisms. The mean diameters of the inhibition zones for the C. albicans cultures were 11.6 mm (17% EDTA), 5.5 mm (0.5% NaOCl), 12.9 mm (1% NaOCl), 22.1 mm (2.5% NaOCl), and 28.5 mm (5.25% NaOCl). The mean diameters of the inhibition zones for E. faecalis were 2.8 mm (1% NaOCl), 5.4 mm (2.5% NaOCl), and 8.3 mm (5.25% NaOCl). For S. aureus, the mean values were 8.0 mm (17% EDTA), 3.0 mm (1% NaOCl), 8.8 mm (2.5% NaOCl), and 10.0 mm (5.25% NaOCl). Most of the irrigant solutions presented effective antimicrobial activity against C. albicans. A high inhibitory effect on the metabolic activity of E. faecalis was detected when the microorganisms were incubated with 17% EDTA. The same result was reached when S. aureus was incubated in the presence of > 2.5% NaOCl. Altogether, these results indicate that 2.5% and 5.25% NaOCl are microbicides against S. aureus while 0.5% and 1% NaOCl are only microbiostatic against the tested bacteria. The 6% and 10% citric acid as well as 17% EDTA did not affect the viability of any of the assayed microorganisms.

Safety and efficacy of topical bacteriophage and ethylenediaminetetraacetic acid treatment of Staphylococcus aureus infection in a sheep model of sinusitis

“…No studies have yet assessed EDTA in an in vivo model of biofilm eradication; however, results in this study reflect similar in vitro observations indicating EDTA to be a potent inhibitor of biofilms as well as being effective against preformed biofilms . The mechanism of EDTA's effect on biofilm is likely due to its metal chelation action.…”

Evaluating the Antimicrobial Efficacy of Root Canal Irrigants Against Candida Albicans And Enterococcus Faecalis: in vitro study

“…Our findings for CHX and NaOCl were in accordance with the literature. 23 Fidalgo et al 24 detected a high inhibitory effect on the metabolic activity of E. faecalis when the microorganisms were incubated with 17% EDTA.…”

An In Vitro Study Comparing the Intracanal Effectiveness of Calcium Hydroxide– and Linezolid-based Medicaments against Enterococcus faecalis

“…Its high pH interferes with bacterial cytoplasmic membrane integrity, causing biosynthetic alteration in cell metabolism and phospholipid destruction (15). The ineffectiveness of using lower concentrations of NaOCl against EF has been reported (16,17). Hence, the highest concentration recommended, 5.25% NaOCl, was used in this study.…”

“…Hence, the highest concentration recommended, 5.25% NaOCl, was used in this study. Although EF has been reported to be sensitive to 5.25% NaOCl, the irrigant is unable to completely eliminate the viability of enterococci (7,17).…”