Nickel allergy and orthodontic treatment.

OBJECTIVES Tolerance induction to prevent development of nickel allergy has been suggested with permanent dental braces. We wanted to find out which effect orthodontic treatments had had on the development of nickel allergy in university students. STUDY DESIGN We examined and patch tested 153 students, of whom 113 had a history of pierced skin, and 70 a history of orthodontic treatment roughly 10 years earlier. RESULTS All except one student with pierced skin were females. Development of nickel allergy was significantly associated with skin piercing (54% compared with 12%). At the time of the study, there was a slight but non-significant difference in the prevalence of nickel allergy between students who had been subjects for orthodontic treatment (49%) compared with non-treated ones (58%) if they had pierced skin. There were no significant differences in the development of nickel allergy among students who had had permanent dental braces before (50%) or after skin piercing (48%). However, from 40 students without skin piercing four of 11 (three males) with a history of permanent braces had developed nickel allergy, as compared with none of 22 (P = 0.008) without orthodontic treatment suggesting possibility of sensitization through dental devices. CONCLUSIONS Orthodontic treatment may not lead to tolerance induction on all occasions, and sensitization through permanent devices seems to be possible.