Method: Specimens of whitening dentifrices (Colgate Total 12 Professional Whitening and Oral-B Whitening), and common dentifrices (Colgate Total 12 Professional Clean and Oral-B) were extracted in culture medium (0.2 g sample weight mL-1). Gingival human fibroblasts (FMM-1) were placed in contact with different dilutions of culture media previously exposed to such dentifrices and the cytotoxicity was evaluated by methol-thiazol-diphenyl tetrazolium (MTT) assay in spectrophotometer to check the viability rate and cell survival. The genotoxicity was accessed by the micronucleus formation assay in Chinese hamster fibroblasts (V79). Cell survival rate and micronuclei number were assessed before and after exposure to dentifrices extracts, and the results were statistically analyzed by Mann-Whitney-U test (P <.05).
Result: The results of MTT assay showed that the Colgate presents statistically significant difference when compared to Colgate Whitening, Oral B and Oral B Whitening in all dilutions (p<.01). Furthermore, it was found that the Colgate Whitening was the most cytotoxic dentifrice, showing values below of 5% in rate of proliferation at all dilutions. In relation to genotoxicity, it was observed that whitening dentifrices showed higher number of micronucleus compared to common dentifrices. Oral B Whitening showed the highest genotoxicity compared to the untreated group (p<.01).
Conclusion: The whitening dentifrices and Oral B common dentifrice presented a high cytotoxicity. However, whitening components in the dentifrices did not able to promote, in general, a significant genotoxicity in vitro.