Effectiveness and mode of action of whitening dentifrices on enamel extrinsic stains

Salem Alshara, Frank Lippert, George J. Eckert, Anderson T. Hara

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Objectives: This study was conducted in order to investigate the mode of action and the whitening effect of whitening dentifrices. Material and methods: Two hundred fifty-six bovine enamel specimens (10 × 10 mm2) were prepared, partially stained, and assigned into eight groups (n = 32): six whitening dentifrices, one nonwhitening and deionized water (negative control), and further divided in two subgroups (n = 16), according to the test model: chemical (dentifrice slurry treatment only) or chemo-mechanical (slurry + toothbrushing). Specimens were treated with dentifrice slurries 2×/day for 1 min and toothbrushed or not, according to each model. In between dentifrice treatments, specimens were artificially stained for 5 h. This protocol was repeated for 5 days and enamel color changes ({increment}E) were measured after each day (days 1-5). The abrasive level of the dentifrices was determined following the ISO11609 guidelines. Results: In the chemo-mechanical model, the whitening action of all dentifrices was observed after day 1, being higher than the negative control group (p < 0.05). In days 2-5, nonsignificant changes in color were observed for all groups (p > 0.05). Differences on {increment}E among dentifrices were observed, and they seemed to correlate well with their abrasive level (r 2 = 0.80). In the chemical model, no significant differences were observed among groups (p > 0.05), with {increment}E remaining constant throughout the study. Higher {increment}E values were observed in the chemo-mechanical model compared to the chemical (p < 0.05). Conclusions: All tested dentifrices were effective in whitening stained enamel and their mode of action showed to be mainly mechanical (toothbrushing abrasion). Clinical relevance: The abrasive level of dentifrices seems to determine its whitening effectiveness.

Original languageEnglish (US)
Pages (from-to)563-569
Number of pages7
JournalClinical oral investigations
Issue number2
StatePublished - Mar 1 2014


  • Dentifrices
  • Enamel
  • Extrinsic stain
  • Spectrophotometry
  • Toothbrushing
  • Whitening

ASJC Scopus subject areas

  • Dentistry(all)

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