title: Changes in surface levels of mercury, silver, tin, and copper of dental amalgam treated with carbamide peroxide and hydrogen peroxide in vitro.
abstract: OBJECTIVE
  The effect of 10% carbamide peroxide or 10% hydrogen peroxide on the surface levels of mercury, silver, tin, and copper of amalgam fillings was tested in vitro with scanning electron microscopy and energy dispersive spectrometric microanalysis.
  
  
  METHODS
  Samples of amalgam were treated for 14 and 28 days with either 10% carbamide peroxide or 10% hydrogen peroxide solutions and compared with phosphate buffer controls.
  
  
  RESULTS
  A significant increase in mercury levels occurred after treatment with carbamide peroxide for 14 days (p < 0.01) and 28 days (p < 0.001) and after treatment with hydrogen peroxide for 28 days (p < 0.001). A significant increase in silver levels occurred after treatment with carbamide peroxide for 14 days (p < 0.05) and 28 days (p < 0.01) and subsequent to treatment with hydrogen peroxide for 14 days (p < 0.05) and 28 days (p < 0.001). A significant reduction in tin levels occurred after treatment with hydrogen peroxide for 14 days (p < 0.01) and 28 days (p < 0.001), and after treatment with carbamide peroxide for 28 days (p < 0.01). A significant reduction in copper levels was found after treatment with carbamide peroxide for 14 days (p < 0.05).
  
  
  CONCLUSIONS
  It appears that prolonged treatment with bleaching agents may cause microstructural changes in amalgam surfaces, possibly increasing exposure of patients to toxic byproducts.
authors.affiliation: Department of Endodontics, Hebrew University-Hadassah Faculty of Dental Medicine, Jerusalem, Israel. rotstein@cc.huji.ac.il
authors.forename: I
authors.initials: I
authors.lastname: Rotstein
authors.forename: C
authors.initials: C
authors.lastname: Mor
authors.forename: J R
authors.initials: JR
authors.lastname: Arwaz
mesh_terms: D000077463:Carbamide Peroxide; D003300:Copper / Q000032:analysis; D003343:Corrosion; D003723:Dental Amalgam / Q000737:chemistry*; D004338:Drug Combinations; D004577:Electron Probe Microanalysis; D006861:Hydrogen Peroxide / Q000737:chemistry*; D008628:Mercury / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D010545:Peroxides / Q000737:chemistry*; D012834:Silver / Q000032:analysis; D013499:Surface Properties; D014001:Tin / Q000032:analysis; D014508:Urea / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D004338:Drug Combinations; D010545:Peroxides; D000077463:Carbamide Peroxide; D012834:Silver; D014001:Tin; D003300:Copper; D003723:Dental Amalgam; D014508:Urea; D006861:Hydrogen Peroxide; D008628:Mercury