EPICUTANEOUS TESTS OF DENTAL ALLOYS

Complaints about ''allergies to dental alloys'' are frequent. Standard ized patch tests with dental alloys are then performed on the patient' s back. However, the stratum corneum provides a barrier to penetration of exogenous chemicals. The quality of this barrier varies, if palata l and epidermal epithelium are compared. In the present study patch te sts of dental alloys were performed on 30 patients with oral complaint s to dental alloys. Three different patch tests were applied to the ba ck and insides of both upper arms. To disturb the permeability barrier , prior to application of the patch test materials, the skin of the in side, right upper arm was delipidized with acetone wipes. The transepi dermal water loss was measured prior to and after the acetone wipes. O f 30 patients tested, 17 patients revealed reactions at least to one s ubstance. Thereof, six patients (36%) reacted to a given substance in all three locations, eight (47%) on both upper arms, and three patient s (17%) reacted only on the acetone-pretreated arm. Reactions to sodiu m thiosulfatoaurate (n = 8), benzoyl peroxide (n = 6), cadmium chlorid e (n = 6), and palladium chloride (n = 6) were frequent. This study sh ows that disruption of the epidermal barrier by acetone wipes is not n ecessary. Patch testing of dental alloys on the inside of the upper ar m is most preferable.