Kobayashi Yoshimi, Hayashi Makoto, Yoshino Fumihiko, Tamura Muneaki, Yoshida Ayaka, Ibi Haruna, Lee Masaichi-Chang-il, Ochiai Kuniyasu, Ogiso Bunnai
Division of Applied Oral Sciences, Nihon University Graduate School of Dentistry.
J Oral Sci. 2014 Mar;56(1):35-9. doi: 10.2334/josnusd.56.35.
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 (H2O2) may be a promising option for increasing bactericidal hydroxyl radical (HO•) generation. In this in vitro experiment, we examined the effects of HO• generated using PUI and a low concentration of H2O2. An ultrasonic tip was submerged in 0.45 mol/L (1.5%) H2O2 in a microfuge tube. H2O2 was activated by an ultrasonic unit, the tip of which was kept centered in the tube, to mimic PUI. HO• generation was detected by electron spin resonance spectroscopy. An Enterococcus faecalis suspension in H2O2 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 (P < 0.05). HO• generation and bactericidal activity were significantly increased by PUI in H2O2 in a time-dependent manner and were significantly higher than with H2O2 alone or with PUI in a Tris-HCl suspension. These results suggest that PUI in the presence of a low H2O2 concentration is a promising new disinfection strategy.
化学机械方法可用于清除根管内的细菌。然而，由于根管系统的复杂性，有时仍可检测到细菌。使用过氧化氢（H2O2）进行牙髓被动超声冲洗（PUI）可能是增加杀菌性羟基自由基（HO•）生成的一种有前景的选择。在这项体外实验中，我们研究了使用PUI和低浓度H2O2产生的HO•的效果。将超声探头浸入微量离心管中的0.45 mol/L（1.5%）H2O2中。通过超声设备激活H2O2，其探头保持在管的中心位置，以模拟PUI。通过电子自旋共振光谱法检测HO•的生成。然后制备粪肠球菌在H2O2中的悬浮液，并按上述方法激活。通过活菌计数评估杀菌效果。采用双向方差分析和Tukey检验评估各组间差异的统计学意义（P < 0.05）。在H2O2中，PUI以时间依赖性方式显著增加HO•的生成和杀菌活性，且显著高于单独使用H2O2或在Tris-HCl悬浮液中使用PUI的情况。这些结果表明，在低浓度H2O2存在下的PUI是一种有前景的新消毒策略。
