加热对内根管温度对与依地酸或 EDTA 混合的次氯酸钠持续螯合稳定性的影响。

The Effect of Heating to Intracanal Temperature on the Stability of Sodium Hypochlorite Admixed with Etidronate or EDTA for Continuous Chelation.

机构信息

School of Dentistry, The University of Queensland, Herston, Queensland, Australia.

出版信息

J Endod. 2019 Jan;45(1):57-61. doi: 10.1016/j.joen.2018.09.014. Epub 2018 Nov 13.

DOI:10.1016/j.joen.2018.09.014

PMID:30446402

Abstract

INTRODUCTION

Tetrasodium etidronate (Na etidronate) and tetrasodium EDTA (Na EDTA) are chelators that can combine with sodium hypochlorite (NaOCl) as a 1-mix endodontic irrigant in a process called continuous chelation. The therapeutic window of these mixtures is determined by the chemical reaction between NaOCl and the chelator. At room temperature, this window is 60 minutes for Na etidronate and 30 minutes for Na EDTA. Because reaction kinetics are influenced by heat, this study assesses the influence of heating to an intracanal temperature of 35°C on the therapeutic window in continuous chelation.

METHODS

The loss of free available chlorine (FAC) in NaOCl mixtures with Na etidronate or NaEDTA was determined by iodometric titration at 23°C ± 0.7°C (23°C) and 34.6°C ± 0.3°C (35°C) at 1, 20, 40, and 60 minutes after mixing. The pH and temperature of the mixtures were measured.

RESULTS

At 23°C, 18% Na etidronate/5% NaOCl solutions at 20, 40, and 60 minutes lost 4%, 9% and 18% FAC, and at 35°C, they lost 20%, 68% and 92% FAC; 5% Na EDTA/2.5% NaOCl solutions at 20, 40, and 60 minutes at 23°C lost 88%, 94%, and 97% FAC, and at 35°C, they lost 96%, 99%, and 100%. Decreases in FAC were accompanied by pH declines.

CONCLUSIONS

The effect of heating to 35°C from a room temperature of 23°C on 18% Na etidronate/5% NaOCl solutions reduces its therapeutic window to 20 minutes. Solutions of 5% Na EDTA/2.5% NaOCl are not useful in the continuous chelation technique. Tracking pH changes could be used to estimate NaOCl degradation.

摘要

简介

依替膦酸钠（Na 依替膦酸盐）和依替膦酸四钠（Na EDTA）是螯合剂，可与次氯酸钠（NaOCl）结合作为 1 混合根管冲洗剂，这一过程称为连续螯合。这些混合物的治疗窗口由 NaOCl 与螯合剂之间的化学反应决定。在室温下，Na 依替膦酸盐的治疗窗口为 60 分钟，Na EDTA 的治疗窗口为 30 分钟。由于反应动力学受热量影响，本研究评估了加热至 35°C 根管内温度对连续螯合治疗窗口的影响。

方法

通过碘量滴定法测定室温（23°C）和 35°C（35°C）时 18% Na 依替膦酸钠/5% NaOCl 混合物和 5% Na EDTA/2.5% NaOCl 混合物中游离有效氯（FAC）的损失。测量混合物的 pH 值和温度。

结果

在 23°C 时，18% Na 依替膦酸钠/5% NaOCl 溶液在 20、40 和 60 分钟时分别损失 4%、9%和 18% FAC，在 35°C 时分别损失 20%、68%和 92% FAC；5% Na EDTA/2.5% NaOCl 溶液在 20、40 和 60 分钟时在 23°C 下分别损失 88%、94%和 97% FAC，在 35°C 下分别损失 96%、99%和 100% FAC。FAC 的减少伴随着 pH 值的下降。