Investigation of p-chloroaniline formation in the reactions between different endodontic irrigants

Ljiljana Bjelović,Marija Živković,Biljana Glišić,Tatjana Kanjevac

doi:10.5937/kgjsci1941043b

Abstract

The aim of this study was to determine whether p-chloroaniline (PCA) is formed in the reactions of sodium hypochlorite (NaOCl) with final rinse chlorhexidine (CHX), QMix (combination of ethylenediaminetetraacetic acid (EDTA), CHX and detergent) and EDTA/CHX solutions by thin-layer chromatography (TLC), proton nuclear magnetic resonance (1H NMR) and infrared (IR) spectroscopy. Commercially available 5.25% NaOCl solution was mixed with 2% CHX and QMix in 1:1 (v/v) ratio at room temperature. Furthermore, 2% CHX was associated with 17% EDTA under the same experimental conditions. The obtained solutions were evaluated qualitatively for color changing, precipitate and/or bubble formation and analyzed by TLC chromatography. The association products were investigated by spectroscopic (1H NMR and IR) methods in order to determine whether they contain PCA. It was found that interactions between NaOCl/CHX and CHX/EDTA led to forming of brown and white precipitate. When NaOCl was mixed with QMix, an orange-brown precipitate was formed. PCA was not detected as a product of the reactions between NaOCl and final rinse solutions of CHX, QMix and EDTA/CHX association.

Highlights

Root canal irrigation, mechanical or chemical, aims to remove debris, lubricate the canal, dissolve organic and inorganic tissues, as well as to prevent smear layer formation or aid its removal (ZEHNDER et al, 2005; HÜLSMANN et al, 2007; HAAPASALO et al, 2014)
Brown and white precipitates were formed in the interactions of 2% CHX with 5.25% NaOCl and 17% ethylenediaminetetraacetic acid (EDTA), respectively, immediately after mixing of these irrigants, while the combination of 5.25% NaOCl with QMix resulted in orange-brown solution coloration and bubbles formation
On the basis of thin-layer chromatography (TLC), 1H NMR and IR measurements, we found that a brown precipitate formed in the reaction between 5.25% NaOCl and 2% CHX does not contain PCA

Summary

Introduction

Mechanical or chemical, aims to remove debris, lubricate the canal, dissolve organic and inorganic tissues, as well as to prevent smear layer formation or aid its removal (ZEHNDER et al, 2005; HÜLSMANN et al, 2007; HAAPASALO et al, 2014). The most commonly used irrigants in endodontic therapy are sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA) and chlorhexidine (CHX) (ZEHNDER et al, 2005; HÜLSMANN et al, 2007; GU et al, 2009; BITTER et al, 2013; HAAPASALO et al, 2014). Previous studies showed that QMix is as effective as 17% EDTA in removal of smear layer or even superior (DAI et al, 2011; STOJICIC et al, 2012). QMix is as efficacious antimicrobial agent as 6% NaOCl and superior when compared to CHX, MTAD (mixture of doxycycline, citric acid and detergent) and solutions of NaOCl with lower concentrations (DAI et al, 2011; WANG et al, 2012)

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