ABSTRACT
A rare and chemically inert metal similar to platinum, palladium occurs at such low concentrations in alloys (e.g., in jewelry or dental fillings) as to pose no notable toxicological hazard. No acute or systemic effects in humans have been reported, other than the observation of allergic sensitization, which can involve the respiratory system, skin, oral mucosa, and eyes, ascribed to contact with the metal itself. Acute contact dermatistis (ACD) and oral mucosal lesions, such as erosive lichen planus, are the principal clinical expression of palladium sensitivity seen in the general population, acquired mainly from the metal in alloys used in dental prostheses which can contain up to 79% of the metal (1,2). Rare cases of immediate type allergy have been reported (3-8). The prevalence of reactions to dental materials has been on the increase since the introduction of palladiumsilver alloys in 1973 as a substitute for other materials containing metals suspected of toxicity or allergenicity, such as mercury and nickel, respectively (9). In Germany, dentists have even been advised to stop using palladium or its alloys because of this trend (10).
