J Conserv Dent. 2012 Jul;15(3):293-7.
Comparative evaluation of the antimicrobial activity of natural extracts of Morinda citrifolia, papain and aloe vera (all in gel formulation), 2% chlorhexidine gel and calcium hydroxide, against Enterococcus faecalis: An in vitro study.
Bhardwaj A, Ballal S, Velmurugan N.

The antimicrobial activity of several natural plant extracts was compared to the chemical antimicrobial agents typically used in dental root canals. The extracts were evaluated at two different depths of dentin. Noni gel exhibited greater antimicrobial efficacy than the other plant extracts. (original abstract available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3410345/).