title: In vitro penetration of the pulp chamber by three brands of carbamide peroxide.
abstract: OBJECTIVE
  Vital tooth bleaching has become a popular procedure for whitening teeth. Most home bleaching products contain 10% carbamide peroxide. The purpose of this in vitro study was to measure the quantity of hydrogen peroxide that reaches the pulp chamber from three carbamide peroxide products: Opalescence, Sparkle, and Rembrandt.
  
  
  METHODS
  Seventy roots of extracted premolars were amputated approximately 3 mm apical to the cementoenamel junction, and the pulp tissues were removed. They were divided into three experimental groups (n = 20) and a control group of 10 teeth. An acetate buffer solution was placed in the pulp chamber before the crown was exposed to the bleaching agent at 37 degrees C for 25 minutes. The buffer solution was removed and reacted with leukocrystal violet and horseradish peroxidase. The optical density of blue color that developed was measured at a wavelength of 596 nm and read from a standard curve for hydrogen peroxide quantity.
  
  
  RESULTS
  The measured amounts of hydrogen peroxide were 3.605 +/- 1.405, 1.282 +/- 0.762, and 0.339 +/- 0.251 micrograms for the Opalescence, Sparkle, and Rembrandt groups, respectively. A statistically significant difference in the hydrogen peroxide levels was observed by analysis of variance (p < .05) among the three groups. It was concluded that the penetration of commercial bleaching products was different even though the products were labeled as having the same 10% carbamide peroxide.
  
  
  CONCLUSIONS
  Carbamide peroxide penetration to the pulp varies significantly for various commercial bleaching products. This may result in different levels of tooth sensitivity or bleaching efficacy.
authors.affiliation: Department of Operative Dentistry, Faculty of Dentistry, Mahidol University, Bangkok, Thailand.
authors.forename: W
authors.initials: W
authors.lastname: Thitinanthapan
authors.forename: P
authors.initials: P
authors.lastname: Satamanont
authors.forename: N
authors.initials: N
authors.lastname: Vongsavan
mesh_terms: D000077463:Carbamide Peroxide; D003742:Dental Devices, Home Care; D003745:Dental Enamel Permeability; D003782:Dental Pulp / Q000737:chemistry; D004338:Drug Combinations; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis*; D010545:Peroxides / Q000737:chemistry*; D014073:Tooth Bleaching; D014508:Urea / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D004338:Drug Combinations; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide