title: Using diazotization to characterize the effect of heat or sodium hypochlorite on 2.0% chlorhexidine.
abstract: BACKGROUND
  The combination of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) results in the formation of a precipitate. In a previous study, we demonstrated the formation of 4-chloraniline (PCA) in the precipitate in an amount directly related to the concentration of NaOCl used.
  
  
  OBJECTIVE
  The aim of the present study was to use a diazotization technique to confirm the presence of an aromatic amine (like PCA) in the NaOCl/CHX precipitate and also in the 2.0% CHX at different temperatures (37 degrees C and 45 degrees C).
  
  
  RESULTS
  The results corroborated the presence of the aromatic amine in the precipitate and in the CHX at 45 degrees C.
  
  
  CONCLUSIONS
  Further investigations of the precipitate should address the bioavailability of PCA leaching out from dentin and its cytotoxicity. Until the precipitate is studied further, it would appear prudent to minimize its formation.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada. basrani@dentistry.utoronto.ca
authors.forename: Bettina R
authors.initials: BR
authors.lastname: Basrani
authors.forename: Sheela
authors.initials: S
authors.lastname: Manek
authors.forename: Edward
authors.initials: E
authors.lastname: Fillery
mesh_terms: D000588:Amines / Q000032:analysis; D001391:Azo Compounds / Q000737:chemistry; D002710:Chlorhexidine / Q000737:chemistry; D004347:Drug Interactions; D006358:Hot Temperature; D009608:Nitrous Acid / Q000737:chemistry; D012388:Root Canal Irrigants / Q000737:chemistry; D012973:Sodium Hypochlorite / Q000737:chemistry
chemical_list: D000588:Amines; D001391:Azo Compounds; D012388:Root Canal Irrigants; D012973:Sodium Hypochlorite; D002710:Chlorhexidine; D009608:Nitrous Acid