The histopathology of oral mucosal lesions associated with amalgam or porcelain-fused-to-metal restorations.

Abstract

To analyse the interface stomatitis patterns of oral lichenoid lesions in contact with amalgam and to compare these with the histologic changes in oral lesions clinically associated with porcelain-fused-to-metal (PFM) restorations. To relate these features to the presence of tissue-bound mercury (Hg). A retrospective analysis of tissue biopsies, with clinical data collected via a complementary questionnaire. 479 biopsies diagnosed in 1987 as 'lichenoid reactions'. From these, we retrieved all with amalgam contact and without candida or medication. From 1990-91, all mucosal lesions stated to be associated with PFM restorations were then retrieved for comparative analysis. The biopsies were examined with routine histologic and autometallographic methods. 77 amalgam-associated lesions were found and could be subdivided into five pre-defined interface stomatitis types. We found 22 lesions associated with PFM and 20 showed histopathologic features similar to those associated with amalgam. Hg accumulations were detected in the majority of amalgam-associated but only in part of the PFM-associated lesions. Amalgam-associated lichenoid lesions present a wide spectrum of histopathologic patterns, corresponding to similar patterns in dermatopathology but with no evidence of association with specific disease. PFM-associated lesions tend to display similar lichenoid features, suggestive of common pathogenetic mechanisms. Hg accumulations may play a role to maintain the chronicity of such lichenoid lesions.