title: Use of a physical barrier to improve efficacy of a paint-on whitening gel: a seven-day randomized clinical trial.
abstract: OBJECTIVE
  This randomized, examiner-blind clinical trial evaluated the impact of a physical barrier on tooth whitening response of a peroxide-containing paint-on gel.
  
  
  METHODS
  A total of 33 adult volunteers, ranging from 18-75 years of age, were randomized to one of two treatment groups: a whitening paint-on gel used alone, or a whitening paint-on gel applied to the tooth surface and immediately covered with a polyethylene strip barrier. Both treatments were used twice a day for seven days, and all subjects used a cavity protection dentifrice and an extra-soft toothbrush twice a day while in the study. Whitening efficacy was assessed using L*a*b* color analysis obtained via digital imaging. Efficacy and safety data were collected at baseline and again at Days 2, 5, and 8.
  
  
  RESULTS
  Use of a whitening gel with a protective barrier resulted in significant (p < or = 0.025) color improvement from baseline (as evident by mean deltab* and deltaL*) at Days 5 and 8, while changes from baseline were not significant for the group using whitening gel alone for the same time points. At Day 2, subjects in the barrier group had a significant (p = 0.046) yellowness reduction (deltab*) relative to baseline. Between-treatment comparisons were significant for deltab* at Days 5 and 8 (p < or = 0.015) and for deltab* whitening improvement slopes for the duration of the study (p < 0.002). Both treatments were well tolerated, and no subjects discontinued treatment due to an adverse event.
  
  
  CONCLUSIONS
  Protecting hydrogen peroxide in the whitening gel from the oral environment with a polyethylene barrier increases the magnitude of the whitening response for a paint-on gel, with results evident as early as after five days of product use.
authors.affiliation: The Procter & Gamble Co., Mason, OH, USA. farrell.s.2@pg.com
authors.forename: Svetlana
authors.initials: S
authors.lastname: Farrell
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Barker
authors.forename: Paul A
authors.initials: PA
authors.lastname: Sagel
authors.forename: Robert W
authors.initials: RW
authors.lastname: Gerlach
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000077463:Carbamide Peroxide; D003124:Colorimetry; D045424:Complex Mixtures / Q000008:administration & dosage; D004338:Drug Combinations; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016877:Oxidants / Q000008:administration & dosage*; D010545:Peroxides / Q000008:administration & dosage*; D016037:Single-Blind Method; D014073:Tooth Bleaching / Q000295:instrumentation / Q000379:methods*; D014508:Urea / Q000008:administration & dosage / Q000031:analogs & derivatives*
chemical_list: C475021:Colgate Simply White Clear Whitening Gel; D045424:Complex Mixtures; D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea