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

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 ( 1 H 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 ( 1 H 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.

Ex Vivo Effect of Novel Lipophosphonoxins on Root Canal Biofilm Produced by Enterococcus faecalis: Pilot Study

“…However, these adverse effects are more common if the chlorhexidine is used as a mouthwash. With respect to root canal irrigation, it is necessary to avoid mixing chlorhexidine and NaOCl during their applications because of their reaction: parachloroaniline is formed as a carcinogenic substance with brown color precipitated into the root canal walls [41][42][43].…”

“…The authors also discovered that the combination of NaOCl and chlorhexidine did not have better antimicrobial activity than chlorhexidine applied alone [45]. Furthermore, in clinical application, it is necessary to avoid mixing chlorhexidine and NaOCl during their applications, as it creates a carcinogenic substance with brown color that precipitates into the root canal walls [41][42][43].…”

The influence of irrigation solutions in the inorganic and organic radicular dentine composition

“…Hence, as there is no known solution to simultaneously eliminate mineral and organic components of smear layer, the currently recommended protocol of irrigation combines the use of NaOCl and a final application of EDTA (9). Although chlorhexidine (CHX) has been suggested as a final flush, this irrigant solution interacts with NaOCl forming parachloranilin (PCA) or a salt when interacts with EDTA (10). PCA acts as a chemical smear layer decreasing the permeability of CHX, especially in apical third (11), and the salt formed by cationic CHX and anionic EDTA reaction may also affect permeability.…”