Background. Adverse effects of dental cast alloys on the health of patients are the problem in clinical practice. The aim of this paper was to describe the case of a patient with discolorated gingivae in the presence of fixed dental restorations and used diagnostic and therapeutic procedures. Case report. A 30-year old patient, presented with the complaints about unsatisfactory esthetic of his fixed dental restorations. He complained about the greyish discoloration of gingivae, inappropriate color of the crowns, and a larger space between the central incisors. Both discolorated and normal gingivae around the fixed dental restorations were taken by excision and the samples of gingivae were examined histopathologically, and by using the Atomic Absorption Spectrophotometry test (AAS). Histopathological examination of the discolorated gingivae showed the presence of non-specific inflammation with a foreign body. AAS revealed the presence of various metals in the samples and the higher metal contents in the samples of discolorated gingivae as compared with the samples of normal gingivae. New metal-ceramic crowns were made for the patient. Conclusion. A main cause of greyish discoloration of gingivae was presence of a metal in gingival tissue. After the excision of discolorated gingivae old metalceramic crowns should be replaced with new crowns.