An in vitro study of the antimicrobial activity of some endodontic medicaments against Enteroccus faecalis biofilms.

The in vitro antimicrobial activity of a series of endodontic medicaments and their bases against biofilms of Enterococcus faecalis was investigated. The medicaments tested were Pulpdent paste, Ledermix paste, a 50:50 Ledermix and Pulpdent mixture, and a replica of Ledermix paste. Bases included methyl cellulose with water, polyethylene glycol (PEG), and PEG with zinc oxide, calcium chloride and the other components (inactives) that make up the Ledermix paste base. Biofilms grown on cellulose nitrate membrane filters were exposed to the medicaments for up to 5 days. The number of surviving colony forming units (CFU) was determined at days 1, 3 and 5. The results were expressed as a bacterial survival index (BSI) when compared to the unexposed control. Pulpdent produced the greatest reduction of BSI, followed by the 50:50 mixture of Pulpdent and Ledermix pastes. Ledermix paste, its replica and the individual bases showed no significant reductions in the BSI for E. faecalis. Within the limitations of this laboratory study, calcium hydroxide containing preparations had greater potential for reducing the survival of E. faecalis in a biofilm environment.