Passive ultrasonic irrigation in the presence of a low concentration of hydrogen peroxide enhances hydroxyl radical generation and bactericidal effect against <i>Enterococcus faecalis </i>

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Author(s)

    • Kobayashi Yoshimi
    • Division of Applied Oral Sciences, Nihon University Graduate School of Dentistry
    • Hayashi Makoto
    • Department of Endodontics, Nihon University School of Dentistry
    • Yoshino Fumihiko
    • Photomedical Dentistry, Department of Oral Science, Graduate School of Kanagawa Dental University
    • Tamura Muneaki
    • Department of Microbiology, Nihon University School of Dentistry
    • Yoshida Ayaka
    • Photomedical Dentistry, Department of Oral Science, Graduate School of Kanagawa Dental University
    • Ibi Haruna
    • Division of Applied Oral Sciences, Nihon University Graduate School of Dentistry
    • Lee Masaichi-Chang-il
    • Yokosuka-Shonan Disaster Health Emergency Research Center & ESR Laboratories, Graduate School of Kanagawa Dental University
    • Ogiso Bunnai
    • Department of Endodontics, Nihon University School of Dentistry

Abstract

Chemomechanical procedures can be used to eliminate bacteria from root canals. However, detectable bacteria sometimes remain because of the complexity of the root canal system. Endodontic passive ultrasonic irrigation (PUI) with hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) may be a promising option for increasing bactericidal hydroxyl radical (HO<sup>•</sup>) generation. In this <i>in vitro</i> experiment, we examined the effects of HO<sup>•</sup> generated using PUI and a low concentration of H<sub>2</sub>O<sub>2</sub>. An ultrasonic tip was submerged in 0.45 mol/L (1.5%) H<sub>2</sub>O<sub>2</sub> in a microfuge tube. H<sub>2</sub>O<sub>2</sub> was activated by an ultrasonic unit, the tip of which was kept centered in the tube, to mimic PUI. HO<sup>•</sup> generation was detected by electron spin resonance spectroscopy. An <i>Enterococcus faecalis</i> suspension in H<sub>2</sub>O<sub>2</sub> was then preparedand activated as described above. Bactericidal effects were assessed by viable counting. Two-way analysis of variance and Tukey's test were used to assess the statistical significance of differences among groups (<i>P</i> < 0.05). HO<sup>•</sup> generation and bactericidal activity were significantly increased by PUI in H<sub>2</sub>O<sub>2</sub> in a time-dependent manner and were significantly higher than with H<sub>2</sub>O<sub>2 </sub>alone or with PUI in a Tris-HCl suspension. These results suggest that PUI in the presence of a low H<sub>2</sub>O<sub>2</sub> concentration is a promising new disinfection strategy. (J Oral Sci 56, 35-39, 2014)

Journal

  • Journal of Oral Science

    Journal of Oral Science 56(1), 35-39, 2014

    Nihon University School of Dentistry

Codes

  • NII Article ID (NAID)
    130003393076
  • Text Lang
    ENG
  • ISSN
    1343-4934
  • Data Source
    J-STAGE 
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