Abstract
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 (∆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 ∆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 ∆E remaining constant throughout the study. Higher ∆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.
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Acknowledgments
This manuscript is part of a thesis submitted by Salem Alshara to the Indiana University, in partial fulfillment of the requirements for the Master degree in Preventive Dentistry. This study was supported by the Dental Erosion–Abrasion Research Program, of the Oral Health Research Institute, Indiana University School of Dentistry. The authors would like to thank Drs. Bruce Matis and Jeffrey A. Platt for their insightful comments and discussions.
Conflict of interest
The authors declare that they have no conflict of interest.
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Alshara, S., Lippert, F., Eckert, G.J. et al. Effectiveness and mode of action of whitening dentifrices on enamel extrinsic stains. Clin Oral Invest 18, 563–569 (2014). https://doi.org/10.1007/s00784-013-0981-8
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DOI: https://doi.org/10.1007/s00784-013-0981-8