title: In vitro colorimetric evaluation of the efficacy of home bleaching and over-the-counter bleaching products.
abstract: OBJECTIVE
  Various bleaching modalities are now offered to patients, either monitored by the dental office or self-directed, for which relative efficiency is unknown. The aim of this in vitro study was to evaluate the ability of bleaching products and protocols to lighten enamel and dentin.
  
  
  METHODS
  Bovine tooth specimens of standardized thickness (2.5 +/- 0.025 mm with similar dentin and enamel thickness) were prepared and stained with whole blood and hemolysate before being submitted to seven supervised or self-directed bleaching regimens: tray-based bleaching using 10% (Opalescence, Ultradent; Nite White, Discus Dental) or light-activated 30% (Metatray, Metatray) carbamide peroxide (CP); 6% (Zoom, Discus Dental) or 9% (TresWhite, Ultradent) hydrogen peroxide (HP); strips (Whitening Strips, Oral B-Rembrandt); and paint-on gel (Paint on Plus, Ivoclar Vivadent) containing 8.1% and 6% HP, respectively. Colorimetric measurements were performed on each specimen side, according to the CIE L*a*b* system, before and after staining, as well as after 5, 10, and the recommended number of bleaching applications.
  
  
  RESULTS
  Color change after recommended number of applications (DEr) varied from 15.72 (Metatray) to 29.67 (Nite White) at enamel and 14.91 (Paint on Plus) to 41.43 (Nite White) at dentin side; Nite White (10% CP) and TresWhite (9% HP) were more effective than Metatray (30% CP) and Paint on Plus (6% HP) after 5 or the recommended number of applications.
  
  
  CONCLUSIONS
  In this in vitro study based on bovine teeth, tray-based systems produced the faster and better bleaching effect, regardless of the product and concentration used, at both enamel and dentin sides.
authors.affiliation: Department of Cariology and Endodontics, School of Dentistry, University of Geneva, Geneva, Switzerland. didier.dietschi@medecine.unige.ch
authors.forename: Didier
authors.initials: D
authors.lastname: Dietschi
authors.forename: Nacer
authors.initials: N
authors.lastname: Benbachir
authors.forename: Ivo
authors.initials: I
authors.lastname: Krejci
mesh_terms: D000818:Animals; D000077463:Carbamide Peroxide; D002417:Cattle; D003124:Colorimetry / Q000379:methods*; D003743:Dental Enamel / Q000033:anatomy & histology / Q000187:drug effects; D003804:Dentin / Q000033:anatomy & histology / Q000187:drug effects; D005782:Gels; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000627:therapeutic use; D008422:Materials Testing; D004366:Nonprescription Drugs / Q000627:therapeutic use*; D016877:Oxidants / Q000008:administration & dosage / Q000627:therapeutic use*; D010545:Peroxides / Q000008:administration & dosage / Q000627:therapeutic use; D011145:Polyvinyls / Q000008:administration & dosage / Q000627:therapeutic use; D011897:Random Allocation; D014073:Tooth Bleaching / Q000295:instrumentation / Q000379:methods*; D014075:Tooth Discoloration / Q000628:therapy; D014508:Urea / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000627:therapeutic use
chemical_list: D005782:Gels; D004366:Nonprescription Drugs; D016877:Oxidants; D010545:Peroxides; D011145:Polyvinyls; C112939:Rembrandt Lighten; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide