Abstract:

Objective    To study the effect of root canal irrigation on the surface morphology of nickel-titanium instruments. Methods    The study was proceeded in Chemistry College of Nanjing University from July 2015 to August 2015. Two new MTwo files without any immersion were subjected to atomic force microscopy（AFM）analysis；then the instruments were dynamically immersed in 5.25% NaOCl and 17% EDTA solutions for 10 min，respectively，thereafter subjected to AFM analysis again. By the software of AFM，the surface roughness was analyzed and three-dimensional images were generated. Record and compare the Ra and RMS values of MTwo file before and after immersion. Results   After 5.25%NaOCl immersion，there was a statistically significant increase in Ra and RMS values. The difference was not statistically significant in Ra and RMS values after 17% EDTA immersion. Three-dimensional images of AFM displayed that the surface morphology of nanostructures was irregular both in the new file and the file after immersion. Conclusion    AFM is preferred as a way to quantitatively analyze the influence of irrigation on the surface morphology of endodontic instruments. The 5.25%NaOCl solution immersion significantly increases the surface roughness of the MTwo instruments，whilst 17% EDTA solution does not alter the surface structure of MTwo file.

Key words: atomic force microscope, nickel-titanium file, roughness, immersion

摘要：

目的    研究两种根管冲洗液对镍钛锉表面微观形貌的影响。方法    于2015年7—8月在南京大学化学院进行研究。选取未经冲洗液浸泡的MTwo新锉2根，使用原子力显微镜（AFM）扫描观察，然后将2根锉分别在5.25%NaOCl和17%EDTA溶液中动态浸泡10 min，之后再次使用AFM扫描。通过AFM自带软件分析器械表面粗糙度并生成三维图像，记录并比较冲洗液浸泡前后的MTwo锉平均粗糙度值（Ra）和均方根值（RMS）。结果              5.25%NaOCl溶液浸泡后的MTwo锉，其Ra和RMS值均高于浸泡前的新锉，浸泡前、后差异具有统计学意义（P < 0.05）；17%EDTA溶液浸泡前后的MTwo锉Ra和RMS值比较，则差异无统计学意义（P > 0.05）。AFM三维图像显示，无论是新锉还是冲洗液浸泡过的锉，其纳米结构上的表面形貌均不规则。结论    AFM是量化分析冲洗液对根管器械表面微观形貌影响较佳的一种方式。5.25%NaOCl溶液浸泡会增加MTwo锉的表面粗糙度，而17%EDTA溶液浸泡未使MTwo锉表面结构产生改变。

关键词: 原子力显微镜, 镍钛锉, 粗糙度, 浸泡