Antimicrobial efficacy of different concentration of sodium hypochlorite on the biofilm of Enterococcus faecalis at different stages of development

• Mohammad Frough-Reyhani ^[4] ; Negin Ghasemi ^[5] ; Mohammadhosien Soroush-Barhaghi ^[1] ; Mahsa Amini ^[2] ; Yousefreza Gholizadeh ^[3]
  1. [1] Assistant Professor, Department of Microbiology, Medical Faculty, Tabriz University (Medical Sciences), Tabriz, Iran
  2. [2] Endodontist at private practice, Tabriz, Iran
  3. [3] Private practice, Tabriz, Iran
  4. [4] Associate Professor, Dental Faculty, Tabriz University (Medical Sciences), Tabriz, Iran
  5. [5] Assistant Professor, Department of Endodontics, Dental and Periodontal Research Center, Dental Faculty, Tabriz University (Medical Sciences), Tabriz, Iran

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• Localización: Journal of Clinical and Experimental Dentistry, ISSN-e 1989-5488, Vol. 8, Nº. 5 (Diciembre), 2016, págs. 480-484
• Idioma: inglés
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• Resumen

  • Persistent infection of the root canal due to the presence of resistance bacterial species, such as Enterococcus faecalis, has always been one of the most important reasons for endodontic treatment failure. This study investigated the antimicrobial efficacy of 1%, 2.5 % and 5% sodium hypochlorite in eliminating E. faecalis biofilms at different stages of development.

    In this study 4-, 6- and 10-week-old E. faecalis biofilms were subjected to one of the following approaches: phosphate-buffered saline solution (PBS) or 1%, 2.5% and 5% NaOCl. Dentin chip suspensions were used for colony forming unit (CFU) counting to estimate remaining E. faecalis counts. Statistical comparison of the means was carried out with Kruskal-Wallis test, and pair-wise comparisons were made by Mann-Whitney U test, at a significance level of P<0.05.

    The results showed that 2.5% and 5% NaOCl completely eliminated E. faecalis biofilms in three stages of biofilm development, whereas 1% NaOCl resulted in 85.73%, 81.88% and 78.62% decreases in bacterial counts in 4-, 6- and 10-week-old biofilms, respectively, which was significantly more than those with PBS (p<0.05).

    The bacteria in mature and old biofilms were more resistant to 1% NaOCl than were the bacteria in young biofilms. Overall survival rate and residual bacteria increased with biofilm aging.