Effectiveness of polyhexamethylene biguanide, chlorhexidine, and calcium hydroxide intracanal medicament against intraradicular mature polymicrobial biofilm: A microbiological study.

To compare the effectiveness of different intracanal medicaments against polymicrobial biofilm formed by Enterococcus faecalis, Staphylococcus aureus, and Candida albicans. Eighty mature human roots with intraradicular polymicrobial biofilm were randomly assigned into four groups (n = 20). Intracanal medicaments 0.2% polyhexamethylene biguanide (PHMB), 2% chlorhexidine (CHX), and calcium hydroxide (CH) were applied into the root canals. Collected dentine samples were tested at 7th, 15th, and 30th day for microbial growth, and the colony-forming units per ml (CFU/ml) were determined. The CFU/ml data were analyzed using unpaired t-test and one-way ANOVA-F comparison test. All medicaments resulted in a significant reduction (P < 0.05) in microbial growth at all time intervals compared to the control group. CHX and PHMB showed a similar reduction in CFU/ml at 7th and 15th day but significantly more than CH at all time intervals. At 30th day, PHMB caused a significantly more reduction in CFU/ml than CHX. All the three tested intracanal medicaments such as CH, CHX, and PHMB Gel were effective in reducing the microbial count. CH has a limited antimicrobial effect against the polymicrobial biofilm found inside the root canal. 2% CHX gel has a time-dependent antimicrobial effect. PHMB has a superior antimicrobial effect in comparison with CHX and CH.