EDTAおよびNaOCl溶液を用いた最終灌流による象牙質浸食の走査型電子顕微鏡による研究

A scanning electron microscopic study of dentinal erosion by final irrigation with EDTA and NaOCl solutions.

抄録

目的:

このin vitro研究の目的は，EDTAとNaOClを用いた最終灌流による歯髄侵食を調べることである．

AIM: The purpose of this in vitro study was to examine dentinal erosion caused by final irrigation with EDTA and NaOCl.

研究方法:

25本の片根のヒトの歯に、ニッケルチタン製のシリーズ29プロファイルの回転式インスツルメントを装着した。A群は6％NaOCl（3mL）で2分間，B群は15％EDTA（3mL）で1分間，C群は15％EDTA（3mL）で1分間，続いて6％NaOCl（3mL）で2分間，D群は15％EDTA（3mL）で3分間，E群は15％EDTA（3mL）で3分間，続いて6％NaOCl（3mL）で2分間の最終灌流を行った．走査型電子顕微鏡（3000倍）を用いて，歯根端から1，3，6mmの位置で象牙質壁の写真を作成した。デブリの量と象牙細管の直径を評価し，一方向性ANOVAとフィッシャーのPLSD検定を用いて統計的に分析した。

METHODOLOGY: Twenty-five single-rooted human teeth were instrumented with rotary nickel-titanium Series 29 Profile Instruments. The teeth were divided into five groups and subjected to final irrigation as follows: group A, irrigated with 6% NaOCl (3 mL) for 2 min; group B, 15% EDTA (3 mL) for 1 min; group C, 15% EDTA (3 mL) for 1 min, followed by 6% NaOCl (3 mL) for 2 min; group D, 15% EDTA (3 mL) for 3 min and group E, 15% EDTA (3 mL) for 3 min, followed by 6% NaOCl (3 mL) for 2 min. Photomicrographs of dentinal walls were produced using a scanning electron microscope (3000 x) at 1, 3 and 6 mm from the apex. The amount of debris and dentinal tubule diameter were evaluated, and values were statistically analysed using one-way ANOVA and Fisher's PLSD test.

結果:

15％EDTA単独で根管を洗浄した場合，象牙質は滑らかで平面的な外観を呈し，象牙細管の開口部は規則的で分離していた。EDTAとNaOCLで根管を洗浄した場合，象牙質は侵食され，象牙細管の開口部は不規則で荒れていた。象牙細管の直径はC群で3.43±0.23μm、E群で3.93±0.44μmに増加し、B群とC群、D群とE群の間に有意差が認められた（P＜0.05）。しかし、EDTA単独よりもEDTAとNaOClの併用の方が、より多くのデブリが除去された（P < 0.05）。

RESULTS: When the root canal was irrigated with 15% EDTA alone, the dentine had a smooth and plane appearance, and dentinal tubule orifices were regular and separated. When the root canal was irrigated with EDTA followed by NaOCL the dentine was eroded and the dentinal tubule orifices were irregular and rough. Dentinal tubule diameter increased to 3.43 +/- 0.23 microm in group C and to 3.93 +/- 0.44 microm in group E. Significant differences were observed between groups B and C, and between groups D and E (P < 0.05). However, more debris was removed by irrigation with EDTA followed by NaOCl than with EDTA alone (P < 0.05).

結論:

6％NaOClによる最終灌流は，15％EDTAによる治療後の象牙質浸食を促進する。

CONCLUSIONS: Final irrigation with 6% NaOCl accelerates dentinal erosion following treatment with 15% EDTA.