title: Randomized clinical trial on the efficacy of 2 over-the-counter whitening systems.
abstract: OBJECTIVE
  The purpose of this clinical trial was to evaluate the efficacy of 2 over-the-counter whitening systems: a liquid whitening gel (5.9% hydrogen peroxide, twice a day for 15 minutes), and a sodium chlorite-based whitening gel applied in a tray system (10 minutes twice a day).
  
  
  METHODS
  Sixty volunteers (minimum shade A3 on 1 maxillary tooth) were selected to participate in this single-blind (examiner-blinded), single-center, 2-group trial. The subjects were randomly divided into 2 groups (n = 30 each) and instructed to bleach their teeth for 2 weeks. Efficacy was measured using the Vita Classical shade guide and a spectrophotometer at baseline, as well as after 2 weeks and 6 months.
  
  
  RESULTS
  For the subjectively measured tooth shades, improvement for maxillary canines was 2.03 +/- 3.67 tooth shades in group 1 and 1.08 +/- 2.19 tooth shades in group 2 after 2 weeks; the maxillary incisors revealed a tooth shade improvement of 0.83 +/- 1.71 tabs in group 1 and 0.73 +/- 2.22 tabs in group 2 (P < .05, except maxillary incisors in group 2; t test). Objectively measured tooth shade scores revealed a change of 0 +/- 0.25 tooth shade tabs (P > .05).
  
  
  CONCLUSIONS
  The bleaching gel containing hydrogen peroxide achieved a slight improvement, and the sodium chlorite-based bleaching gel achieved only a small tooth color improvement. Moreover, subjectively and objectively measured tooth shades revealed considerably different results in the clinical situation.
authors.affiliation: Department of Operative Dentistry and Periodontology, University School of Dental Medicine, Berlin, Germany. catharina.zantner@charite.de
authors.forename: Catharina
authors.initials: C
authors.lastname: Zantner
authors.forename: Foteini
authors.initials: F
authors.lastname: Derdilopoulou
authors.forename: Peter
authors.initials: P
authors.lastname: Martus
authors.forename: Andrej M
authors.initials: AM
authors.lastname: Kielbassa
mesh_terms: D000328:Adult; D002712:Chlorides / Q000627:therapeutic use; D003116:Color / Q000592:standards; D003742:Dental Devices, Home Care; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000627:therapeutic use; D008297:Male; D016877:Oxidants / Q000627:therapeutic use; D017060:Patient Satisfaction; D016037:Single-Blind Method; D013053:Spectrophotometry; D014073:Tooth Bleaching / Q000295:instrumentation / Q000379:methods*; D014075:Tooth Discoloration / Q000628:therapy
chemical_list: D002712:Chlorides; D016877:Oxidants; D006861:Hydrogen Peroxide; C001599:chlorite