RESUMO
To evaluate the combined effect of a mixture of tetracycline, acid, and detergent [MTAD] and Nisin against Enterococcus faecalis [E. faecalis] and Actinomyces viscosus [A. viscosus] biofilms. This study was conducted between June and December 2013 in collaboration with Dental Caries Research Chair, College of Dentistry, King Saud University, Riyadh, Saudi Arabia. Single-species biofilms [n=9/species/observation period] were generated on membrane filter discs and subjected to 5, 10, or 15 minute incubation with MTADN [MTAD with 3% Nisin], 5.25% sodium hypochlorite [NaOCl], or normal saline. The colony forming units were counted using the Dark field colony counter. A 100% bactericidal effect of 5.25% NaOCl was noted during the 3 observation periods; a significant reduction [p=0.000] in mean survival rates of E. faecalis [77.3+13.6] and A. viscosus [39.6+12.6] was noted after 5 minutes exposure to MTADN compared with normal saline [78000000+5291503] declining to almost no growth after 10 and 15 minutes. The survival rates of the E. faecalis and A. viscosus biofilm were no different after treatment with MTADN and 5.25% NaOCl at the 3 observation periods [p=1.000]. A combination of MTAD and Nisin was as effective as NaOCl against E. faecalis and A. viscosus biofilms