Antibacterial Potential of 2.5% Sodium Hypochlorite in Distinct Irrigation Protocols on Enterococcus faecalis Biofilm.

OBJECTIVE: The aim of this study was to evaluate the effect of irrigation methods on antibacterial potential of 2.5% NaOCl on Enterococcus faecalis biofilm. MATERIALS AND METHODS: Enterococcus faecalis biofilms were prepared during 60 days on 48 human root canals and randomized into control and experimental groups using positive and negative pressure irrigation. Bacterial growth was analyzed using turbidity of culture medium followed by UV spectrophotometry, and scanning electron microscopy (SEM) analyses were performed. Mean and standard deviations were used for evaluate the mean optical densities associated to the number of bacteria present culture, and Scheirer-Ray-Hare (an extension of the Kruskal-Wallis test) and Tamhane test to analyze the SEM images in the groups and thirds. Significance was set at 5%. RESULTS: Enterococcus faecalis was still present after root canal cleaning regardless of irrigation methods or bacterial identification methods. CONCLUSION: Positive and negative pressure irrigation protocols using 2.5% NaOCl show a similar capacity to reduce E. faecalis in infected root canals.