title: A clinical study to evaluate the efficacy of a novel tray based tooth whitening system.
abstract: OBJECTIVE
  The study was designed to test the whitening efficacy of a new prefabricated tray based whitening system.
  
  
  METHODS
  A parallel, examiner blind, stratified two group clinical study was carried out in the Department of Fixed and Removable Prosthodontics, Leeds Dental Institute, United Kingdom. Forty-nine male and female subjects aged 18-70 years participated in the study and they underwent both clinical and digital evaluation at baseline, 3, 7 and 14 days, respectively. The non-intervention control group was given no treatment and the test group received a tray based whitening system (Colgate Visible White PF Mint, Colgate Palmolive Company, NY, USA) that uses a 6% hydrogen peroxide gel applied in the tray twice daily for 30 min. Digital images of teeth were captured using a Jai 3CCD digital camera under an annular LED illumination array (SCHOTT North America, Inc., USA) and the data obtained was used to calculate colour parameters (L(*), a(*) and b(*)) and whiteness index WIO.
  
  
  RESULTS
  Clinical data and digital data showed significant difference for the Visible White group from the control group for the mean difference in its values from the baseline to each visit (p<0.001). Digital data showed significant correlation to clinical data.
  
  
  CONCLUSIONS
  In the present study statistically significant tooth whitening was evident after 3 days treatment with the tray based whitening system and colour improved with continued usage over 14 days. It also supports our previous study results that the WIO index is appropriate for assessing changes in tooth whiteness.
authors.affiliation: Turner Dental School, University of Manchester, England, UK.
authors.forename: Naveen
authors.initials: N
authors.lastname: Mohan
authors.forename: Stephen
authors.initials: S
authors.lastname: Westland
authors.forename: Paul
authors.initials: P
authors.lastname: Brunton
authors.forename: Roger
authors.initials: R
authors.lastname: Ellwood
authors.forename: Iain A
authors.initials: IA
authors.lastname: Pretty
authors.forename: Wen
authors.initials: W
authors.lastname: Luo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003116:Color; D003124:Colorimetry / Q000379:methods; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D016877:Oxidants / Q000627:therapeutic use*; D014073:Tooth Bleaching / Q000295:instrumentation / Q000379:methods*
chemical_list: D016877:Oxidants; D006861:Hydrogen Peroxide