Orthodontic appliances in relation to nickel hypersensitivity. A review.

Nickel hypersensitivity is an increasing problem in adolescents, especially in girls, with a prevalence of up to 30%. The presence of nickel in orthodontic appliances and the possibility of causing nickel hypersensitivity has been discussed in case reports. A review of the literature concerning nickel hypersensitivity in relation to orthodontic appliances has shown that the risk is very low for patients who are not nickel hypersensitive at the start of the treatment. A patient who is already nickel hypersensitive at the start of orthodontic treatment may in rare cases show adverse reactions induced by the appliance. The slow long-term release of nickel from orthodontic appliances may induce tolerance to nickel in individuals who are not hypersensitive at the start of orthodontic treatment.