Effectiveness of sodium hypochlorite in root canals infected with Enterococcus faecalis

MARTÍN G.*¹, GANI O.¹, PARAJE G., VISVISIÁN C.¹.

Congreso; SAIO 2012; 2012

Neutralization of bacteria in infected root canals is an essential step for a successful endodontic therapy. Sodium Hypochlorite (NaOCl) is the most common irrigating solution used during chemomechanical preparation, not only because it solves organic components but also for its antibacterial properties, that are increased when it is used sequentially with chelating agents as EDTA. The purpose of the present study was to compare in vitro, the antibacterial effect of NaOCl in three different concentrations on Enterococcus faecalis in root canals. Method: 56 freshly extracted, intact human premolars were used for this experiment, distributed into 4 groups of 14 teeth each. After adequate preparation, the teeth were infected with E. faecalis (ATCC 29212) and incubated for 45 days at 37º C. Following this incubation, the premolars were instrumented with Protaper rotary files and irrigated with NaOCl: Group 1, 1% NaOCl; Group 2, 2.5% NaOCl; Group 3, 5.25% NaOCl and Group 4, 1% NaOCl + 5.25% NaOCl. After instrumentation, the groups 1, 2 and 3 were irrigated with 17% EDTA; and group 4 was irrigated with EDTA followed by 5.25% NaOCl as final irrigation. Two samples were collected from root canals: the first one before instrumentation and irrigation, and the second one after the final irrigation. The samples, followed by serial dilutions, were plated and incubated at 37ºC for 48 hours. The colony forming units (CFUs) grown were counted. The comparative analysis was done by Mann-Whitney test. Results: The most effective irrigant against E. faecalis was 5.25% NaOCl, with a statistically significant difference respect to the other groups (p