Department of Restorative Dentistry, Endodontics Division, Piracicaba Dental School, State University of Campinas - UNICAMP, Piracicaba, SP, Brazil.
Department of Restorative Dentistry, Endodontic Division, São Jose dos Campos Dental School, State University of São Paulo, UNESP, Sao Jose dos Campos, SP, Brazil.
Int Endod J. 2017 Oct;50(10):933-940. doi: 10.1111/iej.12713. Epub 2016 Dec 3.
This clinical study was conducted to investigate the influence of 17% ethylenediaminetetraacetic acid (EDTA) ultrasonic activation after chemomechanical preparation (CMP) on eliminating/reducing oral bacterial lipopolysaccharides (known as endotoxins) and cultivable bacteria in teeth with pulp necrosis and apical periodontitis.
Samples were taken from 24 root canals at several clinical periods: S1 - before CMP; S2 - after CMP; S3 - after EDTA: G1 - with ultrasonic activation (n = 12) and G2 - without ultrasonic activation (n = 12). Root canals were instrumented using Mtwo rotary files. Culture techniques were used to determine the number of colony-forming units (CFU). Limulus amebocyte lysate (LAL) was used to measure endotoxin levels. Friedman's and Wilcoxon signed-rank tests were used to compare the amount of bacteria and endotoxin levels in each period (P < 0.05).
Endotoxins and cultivable bacteria were recovered in 100% of the initial samples (S1). CMP was effective in reducing endotoxins and bacterial load (all with P < 0.05). Higher values of endotoxin reduction were achieved with EDTA ultrasonic activation [G1, 0.02 EU mL (range 0.01-0.75)] compared with the no activation group [G2, 1.13 EU mL (range 0.01-8.34)] (P < 0.05). Regarding bacterial reduction, no statistically significant difference was found in S3, regardless of the group (G1, G2, P > 0.05).
Chemomechanical preparation was effective in reducing bacteria and endotoxins, but could not completely eliminate them. The ultrasonic activation of EDTA was effective in further reducing endotoxin levels in the root canals of teeth with pulp necrosis and apical periodontitis.
本临床研究旨在探讨在牙髓坏死和根尖周炎患牙中，经化学机械预备（CMP）后使用 17%乙二胺四乙酸（EDTA）进行超声激活对消除/减少口腔细菌脂多糖（即内毒素）和可培养细菌的影响。
在几个临床阶段从 24 个根管中取样：S1-在 CMP 之前；S2-在 CMP 之后；S3-在 EDTA 之后：G1-有超声激活（n=12）和 G2-无超声激活（n=12）。使用 Mtwo 旋转锉根管预备。采用培养技术确定菌落形成单位（CFU）的数量。使用鲎变形细胞溶解物（LAL）测定内毒素水平。采用 Friedman 和 Wilcoxon 符号秩检验比较各期细菌和内毒素水平的差异（P<0.05）。
初始样本（S1） 100%回收内毒素和可培养细菌。CMP 可有效降低内毒素和细菌负荷（均 P<0.05）。与无激活组[G2，1.13 EU·mL（范围 0.01-8.34）]相比，EDTA 超声激活组[G1，0.02 EU·mL（范围 0.01-0.75）]的内毒素减少值更高（P<0.05）。在 S3 时，无论组（G1、G2，P>0.05）如何，细菌减少均无统计学差异。
化学机械预备可有效降低细菌和内毒素，但不能完全消除。EDTA 的超声激活可有效降低牙髓坏死和根尖周炎患牙根管内的内毒素水平。
