Method: Sixty enamel blocks were prepared from bovine incisors, stained in a coffee solution for two weeks, stratified and allocated to 6 groups. Samples were stored in artificial saliva 24h prior to all analysis and then submitted to 5000 cycles in an automatic brushing machine. The toothbrushes were applied with a control slurry free of abrasive particles (distilled water-G1) or toothpastes slurries of the following materials: Sensodyne™ Extra Whitening-G2, Colgate™ Sensitive Whitening-G3, Colgate™ Sensitive Pro-Relief-G4, Crest/Oral B™ Pro-Health Whitenning-G5, Colgate™ Cavity Protection-G6. Color analysis was performed using Vita Easy Shade and CIEL*a*b* color system. Surface alterations was analyzed by profilometry, Optical Coherence Tomography (OCT) and AFM. Also, the Knoop indent length was remeasured and the enamel wear was calculated. All of these evaluations were performed at baseline and after treatment. All data was analyzed by one-way ANOVA/Kruskal Walis and Willcoxon Signed rank test/ Mann Whitney.
Result: Surface roughness increased significantly for G2-G5, and AFM showed micrometer details of the abrasive effects. No difference was found between groups regarding enamel wear. For the color measurements, all groups showed an increase in their Lightness-L*. Negative value for Da* were observed for all groups, however, b* values increased after treatment. Delta E showed significant differences between groups; all groups presented DE>4 and only G4 showed DE>8. OCT imaging was able to reveal surface alterations.
Conclusion: Whitening desensitizing toothpastes studied altered some color parameters favoring teeth aesthetics probably due to external stains removal. Surface roughness was directly related to the composition of the abrasive particle, being silica the most aggressive. OCT as an non-destructive technique, stands out as an interesting method for follow up.