Analysis of Nickel and Chromium Levels in the Gingival Crevicular Fluid and Hair of Patients Treated with Fixed Orthodontic Appliances: A Longitudinal Study

Objectives: To analyze the levels of nickel and chromium in the gingival crevicular fluid and hair of patients treated with fixed orthodontic appliance
Methods: : Nickel and chromium ion concentrations were measured in GCF and hair of 15 patients (9 females and 6 males, aged 16-28 years old) who had fixed orthodontic treatment using Atomic Absorption Spectroscopy. The samples were taken before treatment (baseline) and four months later during treatment.Data were analyzed using paired t-tests and Pearson correlation test.
Results: GCF nickel level increased from 3.39µg/g (baseline) to 9.00µg/g (4 months); chromium level increased from 1.88µg/g (baseline) to 6.85 µg/g (4 months). Both of these increases were significant (paired t-test, p=0.000). Hair nickel level increased from 0.14 µg/g (baseline) to 0.42µg/g (4 months); chromium level increased from 0.09 µg/g (baseline) to 0.11µg/g (4 months). Both of these increases were significant (paired t-test, p=0.000) There was no significant correlation between the increase of ion level in GCF with that in hair.
Conclusions: After 4 months of treatment with fixed orthodontic appliances, GCF nickel and chromium levels might increase about 364% and 265%, respectively and hair nickel and chromium levels might increase about 122% and 300%, respectively. There was no significant correlation between the difference (increase) of GCF nickel and chromium levels with the increase of hair nickel and chromium levels.