Efficacy of Chitosan Paste as Intracanal Medication Against Enterococcus Faecalis and Candida Albicans Biofilm Compared with Calcium Hydroxide in an In Vitro Root Canal Infection Model

Abstract

Background Enterococcus faecalis and Candida albicans are frequently found in persistent endodontic infection and are resistant to calcium hydroxide (Ca(OH)2), a commonly used intracanal medication. Thus, an effective and safe antimicrobial medication against such refractory infection is necessary in endodontic retreatment, so we aimed to test the efficacy of chitosan paste against these microorganisms compared with Ca(OH)2 in root canals of extracted human teeth. Methods Thirty-six sterilized human root samples prepared from extracted premolars and upper maxillary incisors were infected with E. faecalis for 14 days, while 32 were infected with C. albicans for 48 hours, for mature biofilm formation. The samples were assigned to 6 groups of intracanal medications: no medication (negative control), 20% Polyethylene glycol (PEG), 20% Propylene glycol (PG), Chitosan+PEG, Chitosan+PG, and Ca(OH)2. After 7 days, intracanal surface dentin was harvested using Protaper next, resuspended, serially diluted and spread on Brain-Heart-Infusion agar (for E. faecalis) and Yeast Extract-Peptone-Dextrose agar (for C. albicans) for colony count. Antimicrobial efficacy was determined as percentage of remaining colony forming unit (CFUs) relative to negative control and analyzed using One-way ANOVA and post-hoc Games-Howell test. The significance level was set at 0.05. Results For E. faecalis, chitosan+PEG and chitosan+PG medication significantly reduced viable bacteria compared with negative control, PEG and PG ( P = 0.001, 0.003, 0.024, respectively for chitosan+PEG; P = 0.002, 0.003, 0.014, respectively for chitosan+PG ). Chitosan+PG also had significantly higher antibacterial activity than Ca(OH)2 (P =0.039). For C.albicans, chitosan+PEG and chitosan+PG, but not Ca(OH)2, showed a significantly lower level of remaining CFUs compared with negative control (P = 0.013 and 0.005, respectively). Conclusion Chitosan paste showed good efficacy as intracanal medication in reducing viable E. faecalis and C. albicans biofilm during 7 days in root canals. In particular, Chitosan+PG was significantly more effective against E. faecalis than Ca(OH)2. Therefore, it could be developed as an effective alternative medication in endodontic retreatment.