title: Clinical evaluation of bleaching agents of different concentrations.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the degree of color change, any rebound effect, and sensitivities associated with using 2 different concentrations of carbamide peroxide in vivo.
  
  
  METHODS
  Twenty-five subjects used 10% and 15% agents in trays for 14 days on different sides of their maxillary arches. Subjects returned in 3 days and at 1, 2, 3, and 6 weeks for evaluation of color change and rebound effect. Shade matching, photographic means, and a colorimeter were used for evaluation. Subjects self-reported gingival and tooth sensitivity on a scale of 1 (no sensitivity) to 5 (severe sensitivity).
  
  
  RESULTS
  After 2 weeks, delta L*, delta a*, delta b*, delta E* and delta shade guide rank means for the 10% whitening agent were 6.50, -1.37, -4.63, 8.79, and -15.40, respectively; for the 15% agent, they were 8.72, -1.63, -5.90, 11.03, and -16.59, respectively. After 6 weeks, delta L*, delta a*, delta b*, delta E*, and delta shade guide rank means for the 10% whitening agent were 3.04, -0.99, -3.19, 5.13, and -13.13, respectively; for the 15% agent, they were 3.48, -1.01, -3.60, 5.58, and -13.65, respectively. Means for gingival sensitivity were 1.18 and 1.21 for the 10% and 15% agents, respectively; means for tooth sensitivity were 1.21 and 1.26 for the 10% and 15% agents, respectively.
  
  
  CONCLUSIONS
  All 3 methods of evaluation revealed a significant difference in the tooth lightness achieved by 10% and 15% products at 2 weeks but no significant difference at 6 weeks. No statistically significant difference was found in gingival or tooth sensitivity.
authors.affiliation: Department of Restorative Dentistry, Indiana University, School of Dentistry, Room S-412, 1121 West Michigan Street, Indianapolis, Indiana 46202, USA. Bmatis@iusd.iupui.edu
authors.forename: B A
authors.initials: BA
authors.lastname: Matis
authors.forename: H N
authors.initials: HN
authors.lastname: Mousa
authors.forename: M A
authors.initials: MA
authors.lastname: Cochran
authors.forename: G J
authors.initials: GJ
authors.lastname: Eckert
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000077463:Carbamide Peroxide; D003116:Color; D003124:Colorimetry; D003743:Dental Enamel / Q000187:drug effects / Q000473:pathology; D003777:Dental Prophylaxis; D004311:Double-Blind Method; D004338:Drug Combinations; D005260:Female; D005500:Follow-Up Studies; D005881:Gingiva / Q000187:drug effects; D006801:Humans; D008297:Male; D008437:Maxilla; D008875:Middle Aged; D009566:Nitrates / Q000627:therapeutic use; D010512:Periodontal Index; D010545:Peroxides / Q000008:administration & dosage* / Q000009:adverse effects; D010781:Photography; D017680:Potassium Compounds / Q000627:therapeutic use; D014073:Tooth Bleaching / Q000379:methods*; D014075:Tooth Discoloration / Q000188:drug therapy / Q000628:therapy; D014098:Toothache / Q000139:chemically induced / Q000517:prevention & control; D014508:Urea / Q000008:administration & dosage* / Q000009:adverse effects / Q000031:analogs & derivatives*
chemical_list: D004338:Drug Combinations; D009566:Nitrates; D010545:Peroxides; D017680:Potassium Compounds; D000077463:Carbamide Peroxide; D014508:Urea; C023844:potassium nitrate