Evaluation of genotoxicity and cytotoxicity, metal ion release induced by metals from orthodontic appliances-An in vivo study

To estimate the concentration of metal ions (Ni, Cr, Fe and Co), cytotoxicity and genotoxicity of buccal mucosal cell in patients being treated with fixed orthodontic appliances.

A total of 50 patients aged between 14–30 years of age were included in the study. Three samples of buccal cells were collected from each orthodontic patient at the following times: T (0)-before insertion of the appliance, T (1)-3 months after insertion of the appliance, T (2)-6 months after insertion of the appliance. Metal ion concentration of buccal cells was evaluated using atomic absorption spectrophotometer (AAS). The buccal cells were also evaluated for genotoxicity (DNA damage) and cytotoxicity (cellular viability) using alkaline comet assay and tryphan blue exclusion dye test respectively.

It was noted that there was a significant (p<0.001) increase in the metal ion concentrations in the buccal cell sample. The comet assay results showed significant DNA damage in the buccal cells whereas the cellular viability showed a decrease over the study period but the decrease was insignificant.

The buccal mucosa cells of patients treated with fixed orthodontic appliances over a period of six months showed significant increases in nickel, chromium, iron and cobalt content, with significant DNA damage and insignificant decrease in cellular viability. Further studies should be carried out to evaluate the effects of these changes over the course of the treatment.