Poudyal Sitashi, Pan Wei-Hong, Zhan Liu
Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
Hospital of Huazhong University of Science and Technology, Wuhan, 430060, China.
J Huazhong Univ Sci Technolog Med Sci. 2014 Jun;34(3):420-424. doi: 10.1007/s11596-014-1294-0. Epub 2014 Jun 18.
This study was aimed to evaluate the effectiveness of solution form of 17% ethylenediaminetetraacetic acid (EDTA) on removing smear layer of root canals at different exposure time periods and to provide scientific basis for EDTA as a choice of root canal irrigation in clinical practice. Twenty-five single-rooted teeth were randomly divided into 5 groups: control group (group A) was given 2.5% NaOCl, and 4 experimental groups were given 2.5% NaOCl and 17% EDTA, including groups B, C, D and E with exposure time of 1, 3, 5 and 7 min, respectively. After preparation of the root canals, the teeth were split along their longitudinal axis, and the root sections were examined under scanning electron microscope for evaluation of smear layer removal and erosion on the surface of the root canal walls. The specimens in group B showed presence of smear layer on the walls of the root canal with no statistical difference from that in group A (P>0.05). In groups C and D, partial removal of smear layer was obtained, and there was no significant difference between the two groups (P>0.05), but there was significant difference in removal of smear layer between group C and group B (P<0.05). Root canal walls in group E specimens showed almost complete removal of smear layer, and the removal of smear layer was significantly different from that in group D (P<0.01). There was no significant change in the structure of the surface of root canal for each sample. It was concluded that combined irrigation with 17% EDTA and 2.5% NaOCl could remove the smear layer with no significant alteration in dentinal structure when the chelating agent was applied for 7 min. At 3 and 5 min of application, partial removal of smear layer was observed and at 1 min negligible removal of smear layer was achieved.
本研究旨在评估17%乙二胺四乙酸（EDTA）溶液在不同暴露时间段对去除根管玷污层的效果，并为EDTA在临床实践中作为根管冲洗剂的选择提供科学依据。将25颗单根管牙随机分为5组：对照组（A组）给予2.5%次氯酸钠，4个试验组给予2.5%次氯酸钠和17% EDTA，其中B、C、D、E组的暴露时间分别为1、3、5和7分钟。根管预备后，沿牙齿纵轴劈开，将牙根断面置于扫描电子显微镜下观察，评估玷污层去除情况及根管壁表面的侵蚀情况。B组标本根管壁有玷污层存在，与A组相比无统计学差异（P>0.05）。C组和D组玷污层部分去除，两组间无显著差异（P>0.05），但C组与B组在玷污层去除方面有显著差异（P<0.05）。E组标本根管壁玷污层几乎完全去除，与D组相比玷污层去除有显著差异（P<0.01）。各样本根管壁表面结构无明显变化。结论是，当螯合剂应用7分钟时，17% EDTA与2.5%次氯酸钠联合冲洗可去除玷污层，且牙本质结构无明显改变。应用3分钟和5分钟时，可观察到玷污层部分去除，应用1分钟时，玷污层去除可忽略不计。
