title: Clinical comparison of two self-directed bleaching systems.
abstract: OBJECTIVE
  This randomized clinical trial compared the clinical efficacy and tolerability of 2 marketed self-directed vital tooth-whitening systems.
  
  
  METHODS
  Balancing for baseline tooth color, self-reported coffee/tea use, and age, 57 adult volunteers were randomized to either a whitening strip containing 6% hydrogen peroxide or a tray-based 10% carbamide peroxide/dentifrice/mouth rinse combination system. Following the manufacturer's directions, the strip group bleached twice daily for 30 minutes, whereas the tray group bleached twice daily for 20-30 minutes, preceded by tooth brushing with a whitening dentifrice and followed by mouth rinsing with a whitening solution. Treatment extended for 14 days, with evaluation at day 7 and again at day 14. Whitening response was measured objectively as L*a*b* from standardized digital images of maxillary anterior teeth. Tolerability was assessed by oral examination and subject interview. Efficacy comparisons were made using analysis of covariance, whereas tolerability was compared using the nonparametric Wilcoxon rank-sum test.
  
  
  RESULTS
  Both treatments resulted in statistically significant (P < 0.01) improvements from baseline for all color parameters. For between-group comparisons, the 6% hydrogen peroxide strips yielded a nearly 3-fold reduction in yellowness (deltab*), a nearly 2-fold improvement in lightness (deltaL*), 2.6 times greater redness reduction (deltaa*), and a more than 2-fold change in overall color (deltaE*) compared to the tray-based combination system. Between-group comparisons were statistically significant for the all color parameters at both the day 7 and day 14 evaluations (P < 0.001). In general, 7-day use of the whitening strips provided significantly greater color improvement relative to the combination dentifrice/gel/rinse system at day 14. In addition, the groups differed significantly (P < 0.05) in bleaching tolerability severity-days, with the strip system demonstrating better overall tolerability compared to the combination system.
  
  
  CONCLUSIONS
  The single-step 6% hydrogen peroxide strips demonstrated better overall clinical response, in terms of both tooth-whitening efficacy and tolerability, than the multiple-step tray-based combination system.
authors.affiliation: Department of Periodontics, University of Florida College of Dentistry, Gainesville, FL 32610, USA. kkarpinia@dental.ufl.edu
authors.forename: Katherine
authors.initials: K
authors.lastname: Karpinia
authors.forename: Ingvar
authors.initials: I
authors.lastname: Magnusson
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Barker
authors.forename: Robert W
authors.initials: RW
authors.lastname: Gerlach
mesh_terms: D000293:Adolescent; D000328:Adult; D000077463:Carbamide Peroxide; D003116:Color; D003802:Dentifrices / Q000627:therapeutic use; D004338:Drug Combinations; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D007091:Image Processing, Computer-Assisted; D007509:Irritants / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009067:Mouthwashes / Q000627:therapeutic use; D016877:Oxidants / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D010545:Peroxides / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D014070:Tooth / Q000033:anatomy & histology / Q000187:drug effects; D014073:Tooth Bleaching / Q000379:methods*; D014098:Toothache / Q000139:chemically induced; D016896:Treatment Outcome; D014508:Urea / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D003802:Dentifrices; D004338:Drug Combinations; D007509:Irritants; D009067:Mouthwashes; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide