title: Comparison of effectiveness of two 10% carbamide peroxide tooth-bleaching systems using spectrophotometric measurements.
abstract: OBJECTIVE
  The purpose of this study was to compare the color changes achieved with two commonly used bleaching systems on the basis of a spectrophotometric analysis.
  
  
  METHODS
  Two commercially available 10% carbamide peroxide bleaching systems were used by a total of 48 individuals. Subjects who had intact natural maxillary anterior teeth void of any restorations or decay that had not been subjected to any prior bleaching were included. Opalescence 10% PF (Ultradent Products Inc., South Jordan, UT, USA) was used by 23 patients for 14 days, whereas Nite White Excel (Discus Dental, Culver City, CA, USA) was applied by 25 patients for the same duration. Tooth colors for the middle one-third region of maxillary central incisors and canines were measured with a spectrophotometer prior to bleaching and after 14 days of bleaching. Color difference deltaE and color coordinates L* (lightness), a* (redness), and b* (yellowness) of CIELAB color system (developed by the Commission Internationale de l'Eclairage) were calculated.
  
  
  RESULTS
  Mean deltaE values for Opalescence ranged from 5.03 to 8.92 and from 5.84 to 9.61 for Nite White. The most significant factor of the color change was b* followed by L* and a*. L* values were higher after bleaching, whereas values for both a* and b* decreased. There were no significant differences between the two systems examined (p < .05).
authors.affiliation: Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, Boston, MA 02115, USA. shigemi_nagai@hsdm.harvard.edu
authors.forename: Shigemi
authors.initials: S
authors.lastname: Ishikawa-Nagai
authors.forename: Takayuki
authors.initials: T
authors.lastname: Terui
authors.forename: Kanji
authors.initials: K
authors.lastname: Ishibashi
authors.forename: Hans Peter
authors.initials: HP
authors.lastname: Weber
authors.forename: Michael
authors.initials: M
authors.lastname: Ferguson
mesh_terms: D000328:Adult; D000077463:Carbamide Peroxide; D003116:Color; D003807:Dentin Sensitivity / Q000139:chemically induced; D004338:Drug Combinations; D005260:Female; D006801:Humans; D008297:Male; D010545:Peroxides / Q000009:adverse effects / Q000627:therapeutic use*; D011145:Polyvinyls / Q000009:adverse effects / Q000627:therapeutic use*; D013053:Spectrophotometry / Q000379:methods; D014073:Tooth Bleaching / Q000009:adverse effects / Q000379:methods*; D014075:Tooth Discoloration / Q000628:therapy*; D014508:Urea / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use*
chemical_list: D004338:Drug Combinations; D010545:Peroxides; D011145:Polyvinyls; C093177:tooth-bleaching agent, Opalescence; D000077463:Carbamide Peroxide; D014508:Urea