Genotoxic effects in oral mucosal cells caused by the use of orthodontic fixed appliances in patients after short and long periods of treatment

Objective This study aimed to evaluate the genotoxic effects in the oral epithelial cells of patients undergoing fixed orthodontic treatment and to compare these to a control group without treatment. The null hypothesis to be tested is that corrective orthodontic treatment at different periods does not cause genotoxic effects in patients. Material and methods An observational cross-sectional study including 74 patients enrolled in corrective orthodontic treatment and 21 control patients, between 11 and 35 years of age, of both genders, participated in the research. Patients undergoing treatment were divided into four treatment groups differentiated by treatment periods: G1, n = 21 (1 month to 12 months); G2, n = 21 (13 to 24 months); G3, n = 23 (25 to 48 months); and G4, n = 9 (over 48 months). Cells were collected by scraping the internal side of the cheek and subsequently placed in tubes containing 0.9% sodium chloride solution. The sample underwent evaluation for genotoxic effects by means of the micronucleus test (MNT). Bivariate analyses were performed using parametric tests ( t test or ANOVA) and nonparametric tests (Chi-square test, Kruskal-Wallis test, Dunn post-test). The adopted level of significance was 5%. Results Statistically significant differences for any of the genotoxic abnormalities (binucleated, trinucleated, karyolysis, piknosis, nuclear buds) were not found except for karyolysis, which was higher in the control group than in G4 ( p < 0.05). Conclusions This study did not demonstrate evidence of genotoxic effects even after long periods of corrective orthodontic treatment. Clinical relevance This study explores genotoxic effects in fixed orthodontic patients.