title: Tooth-whitening activity of a novel home-bleaching system utilising thermal diffusion: a multifactorial simultaneous evaluation of efficacy at cervical, body and incisal tooth sites.
abstract: BACKGROUND
  The ability of a thermal diffusion system (TDS) to promote the tooth-whitening actions of a bleaching gel/bleaching activator combination product (containing a final hydrogen peroxide (H(2)O(2)) content of 10.0% (w/v)) towards discoloured 'smile-zone' teeth was examined.
  
  
  METHODS
  Fifty teeth in 15 participants aged 18-62 years were investigated. The CIE tooth shade parameters L(*), a(*) and b(*), together with Vitapan shade scores (VSSs), were simultaneously recorded at three separate tooth areas (cervical, body and incisal sites) with a novel spectrophotometric monitoring system before treatment, and also at 14 days after completion of a 10-day treatment period in which the product was applied 'at-home' (twice daily).Results The tooth-whitening treatment administered gave rise to extremely significant increases in L(*), and decreases in the a(*) and b(*) shade parameters for each of the tooth areas investigated (p <10(-10)). Post-treatment mean decreases in the VSS values were 8.26, 9.70 and 9.14 for the cervical, body and incisal areas respectively (p <10(-8) in each case). Mean ΔE values determined post-treatment were also very highly significant for each tooth region examined (p <10(-10) in each case).
  
  
  CONCLUSIONS
  The tooth-whitening system tested exerted extremely powerful bleaching actions in all tooth areas investigated. The order of tooth-whitening effectiveness was body > incisal > cervical for Δb(*) and ΔE, and incisal > body > cervical for Δa(*) and ΔL(*), and this may reflect the TDS's ability to promote the penetration of H(2)O(2) to intrinsic stain sites.
authors.affiliation: University of Warwick, Warwick, CV4 7AL, UK.
authors.forename: W
authors.initials: W
authors.lastname: Chan
authors.forename: E
authors.initials: E
authors.lastname: Lynch
authors.forename: M
authors.initials: M
authors.lastname: Grootveld
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D013053:Spectrophotometry / Q000379:methods*; D055471:Thermal Diffusion / Q000502:physiology*; D014073:Tooth Bleaching / Q000379:methods*
chemical_list: D006861:Hydrogen Peroxide