Eradication of Enterococcus faecalis and Candida albicans Biofilms by Cinnamomum cassia Essential Oil Solution as a Root Canal Irrigant

Background: Post-treatment apical periodontitis are persistent infections in tissues surrounding teeth roots, which are the consequence of an endodontic treatment failure. These secondary diseases are mainly caused by etiological pathogens from endodontic origin, especially Enterococcus feacalis and Candida albicans. Currently, post-treatment apical periodontitis become a serious problem for dentists where researches are accented particularly for the development of new antiseptics (known as irrigation solutions). Objective: To propose an alternative irrigation solution based on Cinnamomum cassia essential oil diluted in ethanol. Method: C. cassia essential oil, chemically analyzed by GC/MS, and prepared in 20% ethanol, was evaluated for antimicrobial activity and total eradication of E. faecalis and C. albicans biofilms. The most used irrigation solutions by dentists, namely chlorhexidine digluconate and sodium hypochlorite, were also evaluated for comparison. Obtained data were analyzed statistically using two-way analysis of variance (ANOVA) followed by Bonferroni's test. Results: The obtained results revealed that C. cassia essential oil, consisting mainly of 75% cinnamaldehyde, has shown a strong antimicrobial activity against the studied microbial species whatever their grouping in biofilms or planktonic. In an irrigation assay carried out in vitro, 1.25% C. cassia essential oil has eradicated all E. faecalis and C. albicans viable cells protected in biofilms after 30 seconds of exposure only, while 2% chlorhexidine digluconate and 2.5% sodium hypochlorite requires one and five minutes for the total elimination of studied pathogens, respectively. Conclusion: essential oils prepared in ethanol, in general, are interesting antiseptics which can be used as alternative irrigation solutions for endodontic treatments. C. cassia essential oil is a good example because of its strong antimicrobial activity against biofilms of etiological pathogens responsible for post-treatment apical periodontitis.