In vivo study on metal release from fixed orthodontic appliances in oral mucosa cells

In vivo study on metal release from fixed orthodontic appliances in oral mucosa cells Dr. F. Amini* - Dr. M. Rabbani** - Dr. A. Amjadei*** *- Assistant Professor of Orthodontics Dept. - Faculty of Dentistry – Islamic Azad University (Tehran). **- Assistant Professor, Nuclear Research Center Dept. Iranian Atomic Energy Organ. ***- Dentist. Background and Aim: Fixed orthodontic appliances usually include brackets, bands and archwires made of Stainless Steel, Nickel-Titanium or Nickel - Coballt alloys that can release metal ions. The aim of this study was to evaluate the presence of metal ions in oral mucosa cells. Materials and Methods: Sixty subjects were included in this study. The study group consisted of 30 orthodontic patients (age range, 18±2 years) with fixed orthodontic appliances in both arches. The control group was composed of 30 subjects with an age range of 20±2 years who were not undergoing orthodontic treatment and had no dental restorations. Mucosa samples were collected by gentle brushing of the internal part of the right and left buccal mucosa of all subjects. Nickel, Chromium and Cobalt cellular content was quantified by atomic absorption spectrometry varian and analyzed using Mann Whitney-U and t- test. Results: Nickel ion concentrations in the control and study groups were 12.26±12.9 ppb and 21.7±11.4 ppb, respectively. A statistically significant difference was observed between the two groups (p<0.003). There was no significant difference in the concentration of Chromium ions, between the two groups. Conclusion: Nickel is a strong immunologic sensitizer and chromium and cobalt ions can also cause hypersensivity, dermatitis and asthma. Because of possible adverse biologic effects, scientific research should be directed toward dental materials that not only require mechanic resistance to wear and tear, but also are safe for patients. Key words: Nickel – Chromium - Fixed orthodontic appliances - Oral mucosa.