Background: The main microorganism associated with the failure of endodontic treatments is Enterococcus faecalis. Although several endodontic therapeutics have demonstrated antimicrobial activity against E. faecalis, the antimicrobial effectiveness of chitosan (CsNPs) and silver nanoparticles (AgNPs) included into conventional endodontic sealers for endodontic therapies is still unclear. Aim: The objective of this study was to evaluate the antibacterial activity increment (AAI) of endodontic sealers containing CsNPs and AgNPs as well as some chemical components against E. faecalis by direct contact assays. Methods: CsNPs and AgNPs were synthesized by reduction and ionic gelation methods, respectively. Nanoparticles were characterized by dynamic light scattering and energy dispersive X-ray analysis. The bactericidal activity was tested on monolayers on agar plates and collagen membrane surface assays against E. faecalis. Results: The size of CsNPs was 70.6±14.8 nm and zeta potential was 52.0±5.4 mV; the size of AgNPs was 54.2±8.5 nm, and zeta potential was –48.4±6.9 mV. All materials, single or combined, showed an AAI, especially when CsNPs, chlorhexidine (Chx), and the combination of CsNPs-Chx were added. However, the combination of CsNPs-Chx showed the highest (55%) AAI, followed by Chx (35.5%) and CsNPs (11.1%), respectively. There was a significant statistical difference in all comparisons (p < 0.05). Tubliseal (40%) and AH Plus (32%) sealants showed a higher AAI on E. faecalis in the monolayer test and collagen membrane assay analyzed by scanning electron microscopy. Conclusions: Tubliseal and AH plus sealers combined with nanoparticles, especially CsNPs-Chx, could be used for conventional endodontic treatments in the control of E. faecalis bacteria.

中文翻译：

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牙髓封闭剂和含有壳聚糖和银纳米粒子的药物对粪肠球菌的抗菌活性

背景：与牙髓治疗失败相关的主要微生物是粪肠球菌。尽管几种牙髓治疗剂已证明对粪肠球菌具有抗菌活性，但用于牙髓治疗的传统牙髓封闭剂中包含的壳聚糖 (CsNPs) 和银纳米粒子 (AgNPs) 的抗菌效果仍不清楚。目的：本研究的目的是通过直接接触试验评估含有 CsNPs 和 AgNPs 以及一些化学成分的牙髓封闭剂对粪肠球菌的抗菌活性增量 (AAI)。方法：分别采用还原法和离子凝胶法合成CsNPs和AgNPs。纳米粒子的特征是动态光散射和能量色散 X 射线分析。在琼脂板上的单层和针对粪肠球菌的胶原膜表面测定中测试了杀菌活性。结果：CsNPs大小为70.6±14.8 nm，zeta电位为52.0±5.4 mV；AgNPs 的大小为 54.2±8.5 nm，zeta 电位为 –48.4±6.9 mV。所有材料，无论是单一的还是组合的，都显示出 AAI，尤其是当添加 CsNPs、洗必泰 (Chx) 和 CsNPs-Chx 的组合时。然而，CsNPs-Chx 组合的 AAI 最高（55%），其次是 Chx（35.5%）和 CsNPs（11.1%）。所有比较均存在显着统计学差异（p < 0.05）。Tubliseal (40%) 和 AH Plus (32%) 密封剂在单层测试和通过扫描电子显微镜分析的胶原膜分析中显示出对粪肠球菌的更高 AAI。结论：