title: Color stability of white mineral trioxide aggregate in contact with hypochlorite solution.
abstract: BACKGROUND
  One of the uses of white mineral trioxide aggregate (MTA) is as an apical barrier in immature teeth. Although this treatment has been reported to have high success rates, a number of cases of discoloration have been noted. The aim of this research was to investigate the color stability of white MTA in contact with various solutions used in endodontics.
  
  
  METHODS
  The change in color of white MTA after immersion in water, sodium hypochlorite, or hydrogen peroxide was assessed by viewing the color change on digital photographs and also by using a spectrophotometer. White MTA, white Portland cement, and bismuth oxide were assessed. The changes in the material after immersion in the different solutions were assessed by x-ray diffraction analysis and Fourier transform infrared spectroscopy.
  
  
  RESULTS
  Immersion of white MTA and bismuth oxide in sodium hypochlorite resulted in the formation of a dark brown discoloration. This change was not observed in Portland cement. X-ray diffraction analysis and Fourier transform infrared analysis displayed the reduction of sodium hypochlorite in contact with bismuth oxide and MTA to sodium chloride.
  
  
  CONCLUSIONS
  Contact of white MTA and other bismuth-containing materials with sodium hypochlorite solution should be avoided.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dental Surgery, University of Malta, Msida, MSD, Malta. Electronic address: josette.camilleri@um.edu.mt.
authors.forename: Josette
authors.initials: J
authors.lastname: Camilleri
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D001729:Bismuth / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry*; D003116:Color; D004338:Drug Combinations; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D007101:Immersion; D008422:Materials Testing; D016877:Oxidants / Q000737:chemistry; D010087:Oxides / Q000737:chemistry*; D010781:Photography / Q000379:methods; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012388:Root Canal Irrigants / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D012973:Sodium Hypochlorite / Q000737:chemistry*; D013053:Spectrophotometry / Q000295:instrumentation; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013499:Surface Properties; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D016877:Oxidants; D010087:Oxides; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D017640:Silicates; C086631:mineral trioxide aggregate; D014867:Water; C506393:tricalcium silicate; D012965:Sodium Chloride; C033301:bismuth oxide; D006861:Hydrogen Peroxide; D012973:Sodium Hypochlorite; D001729:Bismuth
keywords: Bismuth oxide; characterization; color stability; dental material; radiopacifier; root-end filling materials