In vivo Study on Release of Nickel, Chromium, and Zinc and DNA Damage in Buccal Mucosa Cells from Patients Treated with Fixed Orthodontic Appliances

Abstract

Background: Fixed orthodontic appliances release metal ions such as nickel (Ni), chromium (Cr), and zinc (Zn), which can initiate DNA damage in oral mucosa cells. Aims and Objectives: Assessment of metal ion levels and possible DNA damage in buccal mucosa cells in patients undergoing fixed orthodontic treatment. Materials and Methods: The present study was undertaken on fifty participants in the age range of 15-40 years visiting the department of orthodontics and dentofacial orthopedics, ABSMIDS, selected after applying inclusion and exclusion criteria. Buccal mucosa cells were scraped using interdental brush and subjected to atomic absorption spectrometry and comet assay to assess the amount of metal ions and DNA damage, respectively, before insertion and at 6 months, 1 year, and 1.5 years after insertion of appliance. Data were analyzed using SPSS software version 17. The mean metal ion levels and cell damage before and after treatment were compared using paired t-test. P < 0.05 was considered statistically significant. Results: Ni ions increased to 62.85 ± 4.81 ppb at the end of 1.5 years from 22 ± 2.3 ppb at baseline before the insertion of appliance, Cr ion levels reached 58.3 ± 5.1 ppb from 20 ± 3.8 ppb, and Zn ion levels reached 562.8 ± 66.5 ppb from 197.4 ± 68.5 ppb, respectively. This result was significant with P < 0.01. A decrease in cell viability and an increase in head diameter, % DNA in tail, and tail length were found at the end of 1.5 years as compared to baseline with P < 0.05. Conclusion: Fixed orthodontic appliances showed an increased metal ion levels and DNA damage to a certain extent which has no clinical impact on buccal mucosa cells in patients with fixed orthodontic appliances.