title: Tooth-whitening efficacy of custom tray-delivered 9% hydrogen peroxide and 20% carbamide peroxide during daytime use: a 14-day clinical trial.
abstract: OBJECTIVE
  The purpose of this 14-day parallel, double blind clinical trial was to evaluate the tooth whitening efficacy of a 9% hydrogen peroxide gel (Colgate Visible White) relative to a 20% carbamide peroxide gel (Opalescence) positive control.
  
  
  METHODS
  Forty-six consenting adults were randomly assigned to use one of the two products. All participants had 6 unrestored maxillary anterior teeth averaging a shade ranking score of 9 (A3) in the Vitapan Classical Shade Guide scale of 1 through 16 (lightest to darkest). Tooth whitening consisted of at-home 30-minute daily self-applications of the assigned product after brushing with a non-bleaching dentifrice. One of two calibrated examiners performed the baseline, 5-day, 7-day, and 14-day tooth shade evaluations for a given participant, utilizing the same Vita guide under unmodified color-corrected lighting conditions. Thirty-seven participants made all visits. Bleaching efficacy was measured with respect to mean shift (reduction from baseline) in rank scores of the maxillary anterior teeth, in which baseline rank scores functioned as covariables.
  
  
  RESULTS
  Both treatment groups exhibited statistically significant mean shade rank score improvements from baseline after 5, 7, and 14 days at 3.14, 3.70 and 4.68 for Colgate Visible White and 1.60, 2.52 and 3.85 for Opalescence.
  
  
  CONCLUSIONS
  Between-group comparison shows that while Colgate Visible White (9% hydrogen peroxide) provides a statistically significant tooth whitening improvement over Opalescence (20% carbamide peroxide) after 5 days of self-application, both products have a similar whitening effect after 7 and 14 days.
authors.affiliation: Research Center, School of Dentistry, Medical Sciences Campus, University of Puerto Rico, San Juan, Puerto Rico. edelgadoc@yahoo.com
authors.forename: Evaristo
authors.initials: E
authors.lastname: Delgado
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Hernández-Cott
authors.forename: Bernal
authors.initials: B
authors.lastname: Stewart
authors.forename: Michael
authors.initials: M
authors.lastname: Collins
authors.forename: William
authors.initials: W
authors.lastname: De Vizio
mesh_terms: D000328:Adult; D000077463:Carbamide Peroxide; D004311:Double-Blind Method; D004338:Drug Combinations; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D010545:Peroxides / Q000008:administration & dosage*; D013997:Time Factors; D014073:Tooth Bleaching / Q000379:methods*; D014508:Urea / Q000008:administration & dosage / Q000031:analogs & derivatives*
chemical_list: D004338:Drug Combinations; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide