title: In vitro evaluation of variances between real and declared concentration of hydrogen peroxide in various tooth-whitening products.
abstract: OBJECTIVE
  The aim of this in vitro study was to analyze the real hydrogen peroxide (HP) concentration in various commercially available tooth-whitening products containing HP and/or carbamide peroxide (CP).
  
  
  METHODS
  Sixteen commercially available tooth-whitening products containing various concentrations of CP or HP were investigated. The products were divided into four groups: dentist-supervised home bleaching products (Group 1, n = 5), in-office bleaching products (Group 2, n = 4), over-the-counter bleaching products (Group 3, n = 3) and whitening toothpastes and rinses (Group 4, n = 4). The peroxide concentration was determined using the oxy-reduction titration method. All the reagents used in the study were of analytic grade and freshly prepared before the experiment.
  
  
  RESULTS
  The HP concentration in various dentist-supervised home bleaching products and in-office bleaching products ranged from 3.02-37.08% (expected range = 3-38%). The HP concentration of over-the-counter whitening products ranged from 1.24-5.57% (expected range cannot be estimated as no concentration of active ingredient was provided). Among whitening toothpastes and rinses, Colgate Plax whitening rinse showed more than 1% HP concentration, whereas it was lower than 0.05% in other whitening toothpastes and oral rinses (expected range cannot be estimated as no active ingredient was mentioned).
  
  
  CONCLUSIONS
  HP concentration of most of the professional tooth-whitening products was different from the expected concentrations, although the deviations were small and most of the products were close to the expected concentration. No concentration of active ingredient was provided for over-the-counter whitening products and no active ingredient was mentioned for whitening toothpastes and rinses.
authors.affiliation: Department of Restorative Dental Sciences.
authors.forename: Abdul
authors.initials: A
authors.lastname: Majeed
authors.forename: Imran
authors.initials: I
authors.lastname: Farooq
authors.forename: Sias R
authors.initials: SR
authors.lastname: Grobler
authors.forename: M H
authors.initials: MH
authors.lastname: Moola
mesh_terms: D000077463:Carbamide Peroxide; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis*; D008422:Materials Testing; D009067:Mouthwashes / Q000032:analysis; D004366:Nonprescription Drugs / Q000032:analysis; D010084:Oxidation-Reduction; D010545:Peroxides / Q000032:analysis*; D017186:Titrimetry; D058205:Tooth Bleaching Agents / Q000032:analysis*; D014100:Toothpastes / Q000032:analysis; D014508:Urea / Q000031:analogs & derivatives* / Q000032:analysis
chemical_list: D009067:Mouthwashes; D004366:Nonprescription Drugs; D010545:Peroxides; D058205:Tooth Bleaching Agents; D014100:Toothpastes; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide
keywords: Tooth bleaching; carbamide peroxide; hydrogen peroxide; tooth whitening