A long-term follow-up of allergy to nickel among fixed prostheses wearers.

Skin allergic hypersensitivity to nickel is well known and well documented in the professional literature. Sixteen partially dentate patients with long-standing histories of recurrent hypersensitive skin reaction to nickel were entered into a clinical trial in 1979. All the patients received crowns or bridges made of an alloy containing 66% of nickel with porcelain fused to the metal framework. During the first three years, annual clinical dental and dermatological investigations were performed on all the subjects, including repeated patch tests. Follow-up examinations took place in 1988 and 1994. None of the subjects had any mucosal or systemic reaction following oral exposure to the nickel containing alloy, nor the exacerbations of skin lesions.