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Published on: February 12, 2015
Influence of smoking on oral cells genotoxicity after at-home bleaching using 22% carbamide peroxide: a cohort study
Rodrigo Rohenkohl Silva1, João Paulo De Carli1, Kauê Collares1
1School of Dentistry, University of Passo Fundo, Campus I, BR 285, Passo Fundo, RS, CEP 99001-970, Brazil.
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%.
