Effect of Long-term Exposure to Endodontic Disinfecting Solutions on Young and Old Enterococcus faecalis Biofilms in Dentin Canals
Effect of Long-term Exposure to Endodontic Disinfecting Solutions on Young and Old Enterococcus faecalis Biofilms in Dentin Canals
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DOI：
10.1016/j.joen.2013.11.026
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发表时间：
2014-04-01
影响因子：
4.2
通讯作者：
Haapasalo, Markus
中科院分区：
文献类型：
--
作者：
Du, Tianfeng;Wang, Zhejun;Haapasalo, Markus
摘要：本研究通过建立牙本质感染模型和激光共聚焦扫描显微镜，研究短期和长期暴露于不同根管消毒溶液对牙本质管内粪肠球菌生物膜的抑菌活性。方法：用粪肠杆菌离心填充半圆柱形牙本质块中的牙本质小管，培养形成1日龄和3周龄的生物膜。牙本质新生和成熟生物膜分别用无菌水、2%氯己定、2%次氯酸钠（NaOCl）和6% NaOCl浸泡3、10和30分钟。处理后用激光共聚焦扫描显微镜，采用活/死细菌活力染色法分析消毒剂杀灭细菌的比例。结果：消毒后3 min的细菌杀灭率低于10 min和30 min （P < 0.05）。粪肠球菌生物膜对细菌的杀灭在前3分钟最快，10分钟后杀灭速度明显减慢。6%的NaOCl对1日龄和3周龄的生物膜都是最有效的抗菌溶液（P < 0.05）。2%氯己定与2% NaOCl对细菌的杀伤效果无显著差异（P < 0.05）。各组新生生物膜的细胞死亡数量均显著高于老龄生物膜（P < 0.05）。结论：消毒液对感染牙本质细菌的杀伤作用具有时间依赖性。然而，在接触前10分钟后，几乎没有额外的杀伤效果。
Introduction: The purpose of this study was to evaluate the antimicrobial activity on Enterococcus faecalis biofilms in dentin canals of short-term and long-term exposure to different endodontic disinfecting solutions by using a dentin infection model and confocal laser scanning microscopy. Methods: Dentinal tubules in semi-cylindrical dentin blocks were filled with E. faecalis by centrifugation and incubated to form 1-day-old and 3-week-old biofilms. The young and mature biofilms in dentin were subjected to sterile water, 2% chlorhexidine, 2% sodium hypochlorite (NaOCl), and 6% NaOCl for 3, 10, and 30 minutes. After treatments, the proportion of bacteria killed by the disinfectants was analyzed by confocal laser scanning microscopy by using LIVE/ DEAD bacterial viability stain. Results: The proportion of killed bacteria was lower after 3 minutes than after 10 and 30 minutes of exposure to the disinfecting agents (P < .05). The killing of bacteria in the E. faecalis biofilms was fastest during the first 3 minutes and slowed down greatly after 10 minutes. Six percent NaOCl was the most effective antibacterial solution against both the 1-day-old and 3-week-old biofilms (P < .05). No significant difference in bacterial killing was detected between 2% chlorhexidine and 2% NaOCl (P > .05). Significantly more cells were killed in young biofilms than in old biofilms in all groups (P < .05). Conclusions: The killing of bacteria in infected dentin by disinfecting solutions is time-dependent. However, little additional killing is obtained after the first 10 minutes of exposure.