EPICUTANEOUS TESTS OF DENTAL ALLOYS

Complaints about ''allergies to dental alloys'' are frequent. Standardized 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 palatal and epidermal epithelium are compared. In the present study patch tests of dental alloys were performed on 30 patients with oral complaints to dental alloys. Three different patch tests were applied to the back and insides of both upper arms. To disturb the permeability barrier, prior to application of the patch test materials, the skin of the inside, right upper arm was delipidized with acetone wipes. The transepidermal water loss was measured prior to and after the acetone wipes. Of 30 patients tested, 17 patients revealed reactions at least to one substance. Thereof, six patients (36%) reacted to a given substance in all three locations, eight (47%) on both upper arms, and three patients (17%) reacted only on the acetone-pretreated arm. Reactions to sodium thiosulfatoaurate (n = 8), benzoyl peroxide (n = 6), cadmium chloride (n = 6), and palladium chloride (n = 6) were frequent. This study shows that disruption of the epidermal barrier by acetone wipes is not necessary. Patch testing of dental alloys on the inside of the upper arm is most preferable.