Nickel hypersensitivity in the orthodontic patient.

Nickel is one of the most common causes of allergic contact dermatitis and produces more allergic reactions than all other metals combined. Currently, several brands of orthodontic wires are made of nickel titanium alloy and potentially have a high enough nickel content to provoke manifestations of allergic reactions in the oral cavity. The objectives of this study were (1) to determine if standard orthodontic therapy can sensitize patients to nickel, and (2) to assess gingival response to nickel-containing orthodontic appliances in patients who are nickel sensitive before treatment. Nickel sensitivity patch tests were conducted to confirm hypersensitivity to nickel. Twenty-nine patients from the Division of Orthodontics, Albert Einstein/Montefiore Medical Center were tested, ranging in age from 12 to 48 years. Of the 29 patients, there were 18 female and 11 males. Five of the patients had a positive nickel patch test, a rate of 18.5%. The five patients that tested positive were all female, meaning that the overall rate for females was 27.7% (5:18). The five female patients sensitive to nickel were followed monthly by intraoral photos and gingival and plaque index scores. The remaining patients began routine orthodontic therapy and were retested 3 months into treatment to see whether sensitization occurred. Two patients converted from an initial negative patch test to a positive test. There may be a risk of sensitizing patients to nickel with long-term exposure to nickel-containing appliances as occurs in routine orthodontic therapy.