title: The whitening effect of chlorine dioxide--an in vitro study.
abstract: OBJECTIVE
  The aim of this study was to investigate the whitening properties and rate of bleaching action of chlorine dioxide and compare them with those of hydrogen peroxide of similar concentration.
  
  
  METHODS
  Sixty bovine central incisor crowns were ground and polished until flat surfaces were obtained. The crowns were subjected to extensive staining cycles of artificial saliva, chlorehexidine and tea before being randomly assigned to three groups: chlorine dioxide (ClO2), hydrogen peroxide (H2O2) and deionised water (H2O). The crowns in each group were subjected to seven 2 min exposure cycles in addition to an extra 30 min cycle. CIE LAB spectrophotometric measurements were taken at baseline, after each 2 min, and each extended 30 min bleaching cycle.
  
  
  RESULTS
  L* for ClO2 specimens was significantly higher only after the first 2 min cycle (p<0.001) while for H2O2 specimens, L* significantly increased after the first two cycles (p<0.001) and continued to increase, at a slower rate, until the end of the treatment cycles. ΔE was significantly greater within H2O2 than within ClO2 specimens (p<0.001).
  
  
  CONCLUSIONS
  Chlorine dioxide whitens teeth at a faster rate than hydrogen peroxide. Specimens treated with chlorine dioxide were significantly lighter than those treated with hydrogen peroxide at the end of the first 2 min application cycle, however, extended exposures did not enhance color.
authors.affiliation: Health Services Research, University of Liverpool, Liverpool, UK. Electronic address: mabilal2003@yahoo.co.uk.
authors.forename: M A
authors.initials: MA
authors.lastname: Ablal
authors.forename: A A
authors.initials: AA
authors.lastname: Adeyemi
authors.forename: F D
authors.initials: FD
authors.lastname: Jarad
mesh_terms: D000818:Animals; D000891:Anti-Infective Agents, Local / Q000009:adverse effects; D002417:Cattle; D002710:Chlorhexidine / Q000009:adverse effects; D017606:Chlorine Compounds / Q000627:therapeutic use*; D003116:Color; D003743:Dental Enamel / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000627:therapeutic use; D007180:Incisor / Q000187:drug effects; D008422:Materials Testing; D010087:Oxides / Q000627:therapeutic use*; D010778:Photochemotherapy / Q000379:methods; D011897:Random Allocation; D012464:Saliva, Artificial / Q000737:chemistry; D013053:Spectrophotometry / Q000295:instrumentation; D013662:Tea; D013997:Time Factors; D058205:Tooth Bleaching Agents / Q000627:therapeutic use*; D019228:Tooth Crown / Q000187:drug effects; D014075:Tooth Discoloration / Q000139:chemically induced / Q000188:drug therapy
chemical_list: D000891:Anti-Infective Agents, Local; D017606:Chlorine Compounds; D010087:Oxides; D012464:Saliva, Artificial; D013662:Tea; D058205:Tooth Bleaching Agents; C025109:chlorine dioxide; D006861:Hydrogen Peroxide; D002710:Chlorhexidine
keywords: Chlorine dioxide; Hydrogen peroxide; Spectrophotometer