Antimicrobial efficacy of endodontic irrigants from Azadirachta indica: An in vitro study

Abstract

Objective. This study analyzed the antimicrobial effect of five irrigants formulated from different parts of the tree Azadirachta indica (Neem) and compared with 2.5% sodium hypochlorite and 0.2% chlorhexidine gluconate through an agar diffusion test. Materials and methods. A clinical isolate of Candida albicans was innoculated on Sabourad Dextrose Agar and Enterococcus faecalis (ATCC 29212) on Sheep Blood Agar. Wells with 6 mm diameter were created in agar and 100 μL aliquiots of each irrigant were introduced to five different wells. After incubation, the largest uniform diameter of the inhibition zone was recorded. Results. The leaf extract of the tree and a mixture of the seed-bark powder dissolved in dimethyl sulfoxide were active against both organisms. The other neem-based irrigants, a leaf powder dissolved in dimethyl sulfoxide, aqueous bark decoction and neem oil, did not possess any antimicrobial efficacy. Sodium hypochlorite completely inhibited growth of C. albicans and the leaf extract had larger inhibition zones than chlorhexidine (p = 0.011) or the seed-bark irrigant (p = 0.008). Against E. faecalis, inhibition zones with chlorhexidine were the largest and differed significantly from sodium hypochlorite (p = 0.039), leaf extract (p = 0.008) and seed-bark irrigant (p = 0.011). Conclusions. Two neem irrigants displayed antimicrobial properties. The efficacy of the standard endodontic irrigants varied depending on the organisms tested. Clinical relevance: Neem-based endodontic irrigants may be formulated for clinical application.

Key Words::

• Azadirachta indica
• sodium hypochlorite
• chlorhexidine gluconate
• Candida albicans
• Enterococcus faecalis

Acknowledgements

We would like to acknowledge the support and expertise of Dr P. Ramkumar and Dr Basavaraj who formulated the leaf extract and bark decoction used in the study. The help and facilities at the Department of Microbiology, Kasturba Medical College, Manipal were invaluable and we would like to thank Dr Sugandhi Rao and Dr Sridevi Y. for their efforts.

Declaration of interest : The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.