Detection of <i>Para</i>-Chloroaniline Resulting from the Interaction between Sodium Hypochlorite and Chlorhexidine Analyzed by Mass Spectrometry

Abstract

5.1% of sodium hypochlorite (NaOCl) mixed with 2% of chlorhexidine (CHX) forms a brown precipitate that corresponds to para-chloroaniline (PCA), whether PCA is formed after the combination of NaOCl, CHX, and ethylenediaminetetraacetic acid (EDTA) by means of electron impact (high resolution and interlaced scanning) and ionization by fast atom bombardment (FAB), was analyzed. The brown precipitate, showed signals 127 and 153 Da, corresponding to p-chloroaniline and p-chlorophenyl isocyanate, respectively. These results were analyzed and compared with signals from the interlaced scanning program and confirmed with high resolution mass spectrometry analysis and compared with the NIST database. The mass spectra of this precipitated after different days confirmed the evolution of byproducts with the presence of a peak m/z = 127, due to the decrease of the fragment m/z = 153, which disappeared after 180 days. A blue and a white precipitate were observed by the addition of CHX (2%) with or without polyethylene glycol, respectively, EDTA (17%) and NaOCl (5.1%) precipitates contain chlorhexidine (m/z = 505), but no PCA was detected. We confirmed that PCA is not formed directly as a byproduct of CHX oxidation, but through the formation of the para-chlorophenyl isocyanate intermediate, which degrades slowly to PCA.

Irrigation in Endodontics: Polyhexanide Is a Promising Antibacterial Polymer in Root Canal Treatment

“…A microbial factor is frequently linked to the onset and progression of pulpitis and periodontitis. Bacteria can enter the pulp space from the carious cavity through the dentine tubules (when the size of the dentine bridge is less than 0.5–0.2 mm), during dental treatment, through the destroyed dentoalveolar junction in marginal periodontitis [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ].…”

“…Medical treatment in endodontics is necessary since even the most flexible instruments are not able to fully contact all of the walls of the root canal, especially with those that are slit-shaped, C-shaped, dumbbell-shaped, and other irregular shapes. After preparation, pathogenic microorganisms remain on the walls of the channels, in isthmuses, ‘fins’, and other difficult-to-reach places, whereby the further reproduction of which can lead to the progression of the inflammatory process and a number of complications [ 13 , 14 , 15 , 16 , 17 ].…”

“…It must remain active in the presence of pus, blood, and other biological fluids. It should be noted that, in addition to the optimal antimicrobial spectrum of action, the ‘ideal irrigant’ should act on the organic components of the biofilms and the inorganic components of the lubricated layer for better disinfection and penetration of siler into dentine tubules [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ].…”

“…Third, the bacteria of endodontic infections exist not only in the form of planktonic suspensions, but also as part of biofilms, highly organized microbial communities united by an organic matrix mainly based on polysaccharides. Extracellular DNA (eDNA), enhancer RNA (eRNA), proteins, lipids, and other biomolecules are present in the matrix [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”

Ex vivo Antimicrobial Evaluation of Different Drugs Using RT-PCR Test

“…The broad-spectrum nature, [7] long-term substantivities, [8]adds to its credibility. But its interaction with sodium hypochlorite results in para-chlorophphenyl isocyanate that degrades slowly to para-chloro-aniline; a carcinogenic product [9].is a major setback for its use as an intracanal medicament.…”