Department of Microbiology, University of Granada, Granada, Spain.
Department of Stomatology, School of Dentistry, University of Granada, Granada, Spain.
Int Endod J. 2019 Jan;52(1):114-122. doi: 10.1111/iej.12986. Epub 2018 Aug 2.
To determine the free available chlorine of 2.5% sodium hypochlorite (NaOCl) alone and combined with 9% etidronic acid (HEDP) in the presence of inhibitors, organic tissue and organic tissue plus dentine debris; to evaluate the influence of dentine debris on the tissue-dissolving capacity of both NaOCl solutions; and to determine the antimicrobial action of these solutions when in contact with organic tissue and organic tissue plus dentine debris.
The available chlorine of the solutions over time in the absence and presence of the inhibitors was measured using a titration method. The organic tissue dissolution by the solutions alone and in the presence of dentine powder was evaluated by weighing bovine tissue specimens before and after exposure to the solutions for 3 and 10 min. For the antimicrobial activity, biofilms of Enterococcus faecalis were exposed to the solutions for 3 min in the absence and presence of organic tissue and organic tissue + dentine debris. The biovolume and percentage of damaged membrane cells of the biofilm were measured by means of confocal microscopy and the live/dead technique. Nonparametric tests were used to determine statistical differences (P < 0.05).
Both inhibitors consumed the free available chlorine of the solutions over time. The presence of dentine debris significantly reduced the tissue dissolution capacity of the NaOCl solutions (P < 0.05). The percentages of biovolume reduction were not affected by the presence of the inhibitors in the two NaOCl solutions, whereas the percentage of damaged membrane cells was significantly reduced (P < 0.001). Overall, a similar behaviour was observed in the NaOCl and NaOCl/HEDP groups.
The presence of organic tissue and organic tissue + dentine debris favoured rapid consumption of the free chlorine of NaOCl and NaOCl/HEDP. This resulted in a decreased ability to dissolve organic tissue without affecting the short-term antimicrobial activity.
确定单独使用 2.5%次氯酸钠（NaOCl）和与 9%依替膦酸（HEDP）联合使用时在抑制剂存在下、有机组织和有机组织加牙本质碎屑中的游离有效氯；评估牙本质碎屑对两种 NaOCl 溶液组织溶解能力的影响；并确定这些溶液与有机组织和有机组织加牙本质碎屑接触时的抗菌作用。
使用滴定法测量溶液在无抑制剂和有抑制剂存在时随时间释放的有效氯。通过称重牛组织标本，评估溶液单独使用和在存在牙本质粉末时的有机组织溶解情况，标本在暴露于溶液 3 分钟和 10 分钟后进行评估。对于抗菌活性，将粪肠球菌生物膜在无有机组织和有机组织+牙本质碎屑存在下和存在下暴露于溶液 3 分钟。使用共聚焦显微镜和活/死技术测量生物膜的生物体积和受损膜细胞的百分比。使用非参数检验确定统计学差异（P<0.05）。
两种抑制剂随时间推移消耗了溶液中的游离有效氯。牙本质碎屑的存在显著降低了 NaOCl 溶液的组织溶解能力（P<0.05）。在两种 NaOCl 溶液中，抑制剂的存在并没有影响生物体积减少的百分比，而受损膜细胞的百分比则显著降低（P<0.001）。总体而言，在 NaOCl 和 NaOCl/HEDP 两组中观察到类似的行为。
有机组织和有机组织+牙本质碎屑的存在有利于快速消耗 NaOCl 和 NaOCl/HEDP 的游离氯。这导致有机组织溶解能力下降，而不影响短期抗菌活性。
