John E Thomas1, Daniel S Sem. 1. Department of Endodontics, Marquette University School of Dentistry, Milwaukee, Wisconsin 53233, USA. johnethomas@gmail.com
Abstract
INTRODUCTION: The purpose of this in vitro study was to determine whether para-chloroaniline (PCA) is formed through the reaction of mixing sodium hypochlorite (NaOCl) and chlorhexidine (CHX). METHODS: Initially, commercially available samples of chlorhexidine acetate (CHXa) and PCA were analyzed with 1H nuclear magnetic resonance (NMR) spectroscopy. Two solutions, NaOCl and CHXa, were warmed to 37 degrees C, and when mixed they produced a brown precipitate. This precipitate was separated in half, and pure PCA was added to 1 of the samples for comparison before they were each analyzed with 1H NMR spectroscopy. RESULTS: The peaks in the 1H NMR spectra of CHXa and PCA were assigned to specific protons of the molecules, and the location of the aromatic peaks in the PCA spectrum defined the PCA doublet region. Although the spectrum of the precipitate alone resulted in a complex combination of peaks, on magnification there were no peaks in the PCA doublet region that were intense enough to be quantified. In the spectrum of the precipitate to which PCA was added, 2 peaks do appear in the PCA doublet region. Comparing this spectrum with that of precipitate alone, the peaks in the PCA doublet region are not visible before the addition of PCA. CONCLUSIONS: On the basis of this in vitro study, the reaction mixture of NaOCl and CHXa does not produce PCA at any measurable quantity, and further investigation is needed to determine the chemical composition of the brown precipitate. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.
INTRODUCTION: The purpose of this in vitro study was to determine whether para-chloroaniline (PCA) is formed through the reaction of mixing sodium hypochlorite (NaOCl) and chlorhexidine (CHX). METHODS: Initially, commercially available samples of chlorhexidine acetate (CHXa) and PCA were analyzed with 1H nuclear magnetic resonance (NMR) spectroscopy. Two solutions, NaOCl and CHXa, were warmed to 37 degrees C, and when mixed they produced a brown precipitate. This precipitate was separated in half, and pure PCA was added to 1 of the samples for comparison before they were each analyzed with 1H NMR spectroscopy. RESULTS: The peaks in the 1H NMR spectra of CHXa and PCA were assigned to specific protons of the molecules, and the location of the aromatic peaks in the PCA spectrum defined the PCA doublet region. Although the spectrum of the precipitate alone resulted in a complex combination of peaks, on magnification there were no peaks in the PCA doublet region that were intense enough to be quantified. In the spectrum of the precipitate to which PCA was added, 2 peaks do appear in the PCA doublet region. Comparing this spectrum with that of precipitate alone, the peaks in the PCA doublet region are not visible before the addition of PCA. CONCLUSIONS: On the basis of this in vitro study, the reaction mixture of NaOCl and CHXa does not produce PCA at any measurable quantity, and further investigation is needed to determine the chemical composition of the brown precipitate. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.
Authors: Morgana Eli Vianna; Brenda P F A Gomes; Vanessa Bellocchio Berber; Alexandre Augusto Zaia; Caio Cezar Randi Ferraz; Francisco José de Souza-Filho Journal: Oral Surg Oral Med Oral Pathol Oral Radiol Endod Date: 2004-01
Authors: Colin Eliot; John F Hatton; Gregory P Stewart; Charles F Hildebolt; M Jane Gillespie; James L Gutmann Journal: Odontology Date: 2013-01-19 Impact factor: 2.634