Antimicrobial Activity of Irrigants in a Co-culture of Macrophages-E.faecalis

Objectives: To compare the antimicrobial effect of sodium hypochlorite and Microdacyn 60 in a co-culture of macrophages-Enterococcus faecalis at different concentrations.
Methods: RAW 264.7 macrophages (ATCC) were subculture at 2x10⁵ cells/mL and were infected with E. faecalis at 0.5 on the McFarland scale for 5 hours. Sodium hypochlorite was inoculated at 0-2.5% and Microdacyn 60 at 0-2.5%. The co-culture was incubated for 24 hours at 37 °C, 5% CO₂ and 95% relative humidity. Cell viability was determined by the MTT method. A control group of E. faecalis, macrophages, co-culture without treatment and positive control with chlorhexidine was used. The data were analyzed with Shapiro-Wilks normality tests and paired t-student tests from triplicate of three independent experiments.
Results: Sodium hypochlorite and Microdacyn 60 showed a bacteriostatic effect at high concentrations with moderate cytotoxicity in contact with macrophages.
Conclusions: None of the compounds show bactericidal effects. Sodium hypochlorite remains an effective entodontics irrigant at a 2.5% concentration. Enterococcus faecalis was not very sensitive to sodium hypochlorite, and its effect was only the first 24 hours.