In reply
We acknowledge the points raised by Pigatto et al regarding our research team’s recent publication on allergy to mercury and OLP.1 Pigatto et al report that the presence of organic mercury in dental plaque and calculus is caused by bacterial biotransformation of inorganic mercury associated with dental amalgam fillings. Our team found that cross-reactivity between the inorganic mercurials (ammoniated mercury, metallic mercury, and amalgam) and the organic mercurials (thimerosal and phenylmercuric salts) may also be important in the pathogenesis of OLP. In 2 patients with OLP, patch-test reactions were positive to ammoniated mercury, metallic mercury, and thimerosal.1 This underlies the clinical importance of patch testing with both organic and inorganic mercury compounds in patients with OLP.2,3