Forty-nine consecutive patients with clinically diganosed oral lichnoid reactions in contact with amalgam fillings were studied clinically and histologically. The long-term effect of replacement of these fillings was also examined.

RESULTS.

Seventeen (35%) patients showed positive reactions to mercury at the epicutaneous patch test that was carried out before treatment. After treatment, total regresssion of the lesions was found clinically in 33 (69%) and histologically in 26 (55%) patients. Most of the remaining lesions changed clinically and histologically to a less pronounced tissue reaction. Lesions in direct contact with amalgam fillings (group I) showed significantly better healing results than lesions that exceeded the contact area (group II). No difference in healing capacity was noted in the two groups between patients with positive patch reactions to mercury compared with those with negative reactions. Lesions that histologically were classified as benign oral keratosis showed a similar healing pattern as those classifiec as oral lichen planus.

CONCLUSION.

In group I all lesions changed histologically and clinically to a normal mucosa or to a less affected tissue reaction. In group II this change was less involved in the cause of these lesions. The results suggest that various etiological factors cannot be predicted by epicutaneous patch testing and biopsies.