Efficacy of chitosan root canal medicament against cross-kingdom dual-species biofilm of Candida albicans and Enterococcus faecalis in an in vitro root-canal model.

Infection of the root canals with cross-kingdom biofilm of Candida albicans (C. albicans) and Enterococcus faecalis (E. faecalis) causes more inflammation and is resistant to conventional medication. This study aimed to evaluate the efficacy of chitosan paste (chitosan + propylene glycol (PG)) against this dual-species biofilm in comparison to calcium hydroxide (Ca(OH)2) in the root canals of human teeth. Fifty extracted single-rooted human teeth were prepared and inoculated with C. albicans and E. faecalis, and incubated for 3 days for biofilm formation. Four experimental groups (N = 10 each) were applied with different root canal medications for 7 days, including (1) No medication (negative control); (2) Ca(OH)2 + distilled water; (3) PG (vehicle control) and (4) chitosan + PG. The efficacy of root canal medicaments was assessed by determining the percentage of remaining colony-forming units (CFUs) of viable microorganisms in intracanal dentin. The dentin was collected, serially diluted, and spread on solid media for colony count. The biofilm structure in root canals at 3 days and 10 days (ie. before and after treatments) were observed with scanning electron microscopy (SEM) at 5000× and 10,000× magnifications. Data were analyzed using Welch's ANOVA and Games-Howell post-hoc test (α = 5%). The results show that Chitosan + PG group had a significantly lower percentage of remaining microorganisms when compared to PG, Ca(OH)2, and negative control groups (P-value = 0.015, 0.005, and < 0.001, respectively). Consistently, SEM showed the lowest amount of remaining biofilm in Chitosan + PG group. Thus, Chitosan + PG paste was the most efficacious root canal medicament against dual-species biofilm of C. albicans and E. faecalis in this model.