Assessment of cytotoxic and genotoxic effects of conventional and whitening kinds of toothpaste on oral mucosa cells.

OBJECTIVE: This study aimed to evaluate possible DNA damages to oral epithelial cells exposed to whitening kinds of toothpaste considering the effect of conventional non-whitening toothpaste. MATERIALS AND METHODS: Sixty volunteers were assigned into three experimental groups, each of them using a different regular toothpaste for the initial 2 months, followed by the use of whitening kind of toothpaste of the same brand for next 2 months. The oral epithelial cells were sampled prior and 30, 60, 90 and 120 days after the beginning of the use of tested kinds of toothpaste. Chromosomal damages were analyzed by micronucleus assay. RESULTS: For just one kind of tested whitening toothpaste was observed the significant increase in the number of micronucleated cells after 60 days of use compared values obtained 60 days of usage of conventional non-whitening toothpaste (6.35 ± 3.67 and 2.8 ± 1.91; p < .05). There was no statistically significant difference in other micronucleus assay endpoints between tested types of toothpaste at either of the sampling times during the period of toothpaste application. CONCLUSIONS: Based on the results, it can be concluded that the use of certain whitening kinds of toothpaste may cause a limited biologically insignificant genotoxic effect on buccal epithelial cells.

Cytogenetic damage in exfoliated oral buccal cells by dental composites.

PURPOSE: To evaluate the possible geno/cytotoxic effects of dental composite materials by assessing the frequency of micronuclei formation and other nuclear abnormalities in the exfoliated buccal epithelium. METHODS: Swabs were taken from the buccal mucosa of 85 young healthy subjects. All participants had healthy dentition or dentition restored only with composite materials. Genotoxicity and cytotoxicity was assessed by micronucleus assay. RESULTS: The results indicated no significant difference in number of oral mucosa cells with micronuclei in subjects with different numbers of composite restored tooth surfaces (P= 0.476). Also, the number of restored surfaces had no effect on nuclear alterations closely related to cytotoxicity, such as karyolysis (P= 0.572), karyorrehexis (P= 0.573) and picnosis (P= 0.765). CLINICAL SIGNIFICANCE: Despite doubts about the safe clinical use of resin composites, this study found no evidence that composite materials trigger long-term cytogenetic damage in the epithelial cells of buccal mucosa in humans. There is no objective and quantifiable evidence of genotoxicity induced by composite restorative materials in clinical practice.