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

Cytotoxicity and genotoxicity of whitening toothpastes in buccal mucosal cells: a randomized controlled trial

OBJECTIVES

To assess genotoxic and cytotoxic effect of commercially available toothpastes with the different whitening ingredients.

MATERIALS AND METHODS

In vivo assessment of cytotoxicity and genotoxicity of whitening toothpastes with different ingredients using a buccal micronucleus cytome assay (BMCyt assay) comprised 199 participants randomly divided into ten groups based on used whitening or control/conventional toothpaste. The exfoliated buccal mucosal cells were collected, stained, and microscopically evaluated at baseline (T0), 30 days (T1), and 60 days (T2) after the beginning of treatment and 30 days after completing treatment (T3). Statistical evaluation was performed by repeated-measures analysis of variance (two-way ANOVA), Tukey's test, and multiple regression analysis.

RESULTS

The genotoxic parameters showed no biologically significant changes in any of the observed period for the tested toothpastes, while cytotoxic parameters (number of cells with karyorrhexis and condensed chromatin) showed statistically significant difference (P < 0.05) among evaluation periods for the three peroxide-containing toothpastes.

CONCLUSIONS

Peroxide-containing whitening toothpastes exhibit an increase in certain cytotoxic parameters only during the application period, which return to control values after the cessation of application.

CLINICAL SIGNIFICANCE

Whitening toothpastes show no genotoxic effect, while peroxide-containing whitening toothpastes may present significant increase of cytotoxicity (measured by the number of karyorrhexis and condensed chromatin) during the application period. However, these changes observed in clinical conditions cannot be considered significant.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04460755.

Clinical Prospective Assessment of Genotoxic and Cytotoxic Effects of Fluoride Toothpaste and Mouthwash in Buccal Mucosal Cells

Background: Fluorides are an essential component of oral hygiene products used to prevent dental decay. Therefore, a question arises about the potential harms of joint use of fluoridated toothpaste and mouthwashes regarding the increased amount of fluoride in the oral mucosa. Methods: This prospective, double-blinded parallel randomized clinical trial was conducted using a buccal micronucleus cytome assay (BMCyt assay). Forty-one participants were randomly assigned to the two groups. All participants used the same kinds of toothpaste for 12 weeks, designed explicitly for this study (non-fluoride, 1050 ppm F, and 1450 ppm F each for 4 weeks). Simultaneously, during the 3 months of the research, one group used mouthwash with fluoride (450 ppm) and another without fluoride. The buccal mucosal sampling was taken before using the tested products and after 4, 8, and 12 weeks of their use. Results: The frequency of micronuclei and the majority of other scored endpoints from the BMCyt assay showed no statistically significant differences within and between the studied groups. Comparing two groups, only statistically significant increases in the number of cells with nuclear buds (p = 0.048) and karyorrhexis (p = 0.020) at four weeks of usage were observed in the group that used mouthwash with fluoride. Conclusion: On the basis of the results, it can be concluded that simultaneous application of fluoridated toothpaste and fluoride mouthwash does not lead to cytogenetic damage in buccal mucosal cells.

Prevalence and Characteristic of Oral Mucosa Lesions

(1) Background: Oral mucosa lesions (OMLs) are diagnosed worldwide in any population, age or gender, but in varied prevalence. OMLs can be found in each site of the oral mucosa; for some of them, it is characteristic to have a bilateral/symmetrical or unilateral/nonsymmetrical mucosal manifestation. The knowledge about its prevalence in varied populations can be useful from a clinical point of view. The aim of this study is to assess the prevalence of OMLs in patients attending outpatient dental clinic; (2) Retrospective analysis of 2747 patients’ oral cavity medical charts, who referred to oral pathology outpatient clinic. The type of diagnosed oral lesion, sex and age were evaluated. p ≤ 0.05 was considered statistically significant; (3) Results: In this study, the overall prevalence of oral mucosal lesions was found to be higher in older than younger patients. In our study, the age median was the highest in patients with xerostomia, burning mouth syndrome, angular cheilitis and oral candidiasis. The youngest median age was observed in patients with aphthae, mucocele and gingival enlargement. The higher OMLs frequency was related with the female gender. (4) It is important for clinicians to be familiar not only with distinctive features, which sometimes may not be clear, but also with linking the occurrence of OMLs with the gender and age.

Influence of smoking on oral cells genotoxicity after at-home bleaching using 22% carbamide peroxide: a cohort study

OBJECTIVE

This study evaluated the influence of smoking on the oral cells genotoxicity before and after at-home bleaching using 22% carbamide peroxide (CP).

MATERIALS AND METHODS

This is a prospective observational analytics cohort study which evaluated nonsmokers (NS; n = 24) and smokers (S; n = 16) patients. At-home bleaching was performed using 22% CP gel in individual trays for 1 h per day for 14 days in both groups. Scrapped cells from marginal gums were collected before the bleaching treatment (D0-baseline) and 1 day (D1), 15 days (D15), and 1 month (D30) after its finishing. Cells were stained with Giemsa 10%, and the micronucleus (MN) and metanuclear alterations (MA) were counted by a trained operator in 1000 cells per patient. The collections and data analysis occurred blindly. Data was analyzed by Kruskal-Wallis, Dunn, and Mann-Whitney test (α = 0.05).

RESULTS

MN frequency was not influenced by smoking or bleaching. An increase of MA was observed between D0 and D30 for both groups (p < 0.001); however, no statistical difference was found between NS and S (p > 0.05) in the evaluation times.

CONCLUSION

Smoking associated with 22% carbamide peroxide gel for at-home bleaching does not show genotoxic potential analyzed by the MN counts. However, a significant increase of MA was found for smokers and nonsmokers.

CLINICAL RELEVANCE

Despite of the increase in MA, smoking associated with 22% CP peroxide at-home bleaching showed no important genotoxic potential (MN) for oral cells. Therefore, at-home bleaching treatment is safe for nonsmokers and smokers even with a high carbamide peroxide concentration of 22%.

In vivo evaluation of fluoride and sodium lauryl sulphate in toothpaste on buccal epithelial cells toxicity

OBJECTIVES

The present study addresses the effect of fluoride and sodium lauryl sulphate content of toothpaste on oral epithelial cells in vivo conditions.

SUBJECTS AND METHOD

Forty volunteers were assigned into two experimental groups, each of them applying the different brand of toothpaste. Every group has been using three different types of toothpaste (non-fluoride and non-SLS, fluoride and non-SLS, and the fluoride and SLS) of the same brand for 6 months, each for 2 months. The buccal epithelial cells were sampled at baseline and 30, 60, 90, 120, 150 and 180 days after the beginning of the research. Effect on DNA damage was analyzed by micronucleus assay Results: After 60 days of use, for both tested kinds of toothpaste with fluoride and without SLS, all studied parameters were not significantly different from the results obtained at the time when the participants used a non-fluoride toothpaste. While, after 60 days of use, for one kind of toothpaste with SLS and fluoride, was observed significantly higher incidence of pyknotic cells (2.20 ± 0.95, 0.00 ± 0.00 vs. 0.05 ± 0.22, respectively; p = .001), cells with karyorrhexis (2.35 ± 1.14, 0.85 ± 0.93 vs. 0.40 ± 0.68, respectively; p = .001), and nuclear buds (1.35 ± 0.68, 0.45 ± 0.51 vs. 0.45 ± 0.60, respectively; p = .001), compared to toothpastes of the same brand with fluoride and without SLS, and without fluoride and without SLS, for the same period.

CONCLUSIONS

Based on the results, can be concluded that there is no fluorine-dependent cytotoxic or genotoxic effect, while SLS dentifrice increases the number of nuclear morphological changes in buccal epithelial cells.