In vivo study of metal content of oral mucosa cells in patients with and without fixed orthodontic appliances

Objective - To compare the concentration of nickel, chromium and cobalt in oral mucosa cells of patients with and without fixed orthodontic appliances. Materials and Methods - A total of 60 patients were included in this study. The control group consisted of 30 patients without any type of fixed orthodontic appliances or metal restoration in the mouth (20 females and 10 males from 16 to 20 years with a mean age of 18 years). The test group consisted of 30 patients who had fixed orthodontic appliance in their upper and lower arches (20 females and 10 male from 16 to 20 years with a mean age of 18.2 years). The metal content determinations were carried out using atomic absorption spectrophotometry with a graphite furnace. Results - According to spectrophotometric analysis, no significant differences in chromium (p = 0.09) and cobalt (p = 0.10) content of oral mucosa cells were found between the test and control samples. The nickel content in mucosa samples was significantly higher (p = 0.003) in orthodontic patients compared with the controls. The mean levels of nickel in control and orthodontic patient group were 12.26 and 21.74 ng/ml, respectively. Conclusion - Our findings indicate that there was no difference in the concentration of chromium and cobalt in oral mucosa cells of patients with or without fixed appliances. However, a significantly higher concentration of nickel can be found in oral mucosa cells of patients wearing fixed orthodontic appliances. Continued follow-up is needed to determine the long-term significance of nickel release.