[P494] Oral mucosal pigmentation in a patient with gold alloy dental crown

Diagnosis of pigmented lesions of the oral cavity is challenging because it can be physiological or pathological, and exogenous or endogenous. Amalgam tattoo is one of the most frequent causes of exogenous pigmentation in oral mucosa. Dental amalgam restorations are primarily composed of silver and mercury with smaller amounts of other elements such as tin. The silver particles stain the reticulin fibers leading to the tattoo. Usually, a biopsy may be unnecessary if mucosal pigment exhibits a blue-gray color in a patient that reports a history of dental amalgam restoration. However, if there is no history of amalgam restoration, you may be embarrassed to make a diagnosis and a biopsy is indicated to safely rule out mucosal melanoma. An 80-year-old woman was presented with an accidently found hyperpigmented macule on left lower gingiva. She was asymptomatic and had not any medical history, except for several dental restorations. Clinically, it was shown as blue-gray macule close to gold dental crown. Although amalgam tattoo was suspected, she has no history of dental restoration with amalgam. We underwent a biopsy and the diagnosis was confirmed as an amalgam tattoo. We reviewed literature but could not find a report of amalgam tattoo caused by gold dental crown, but found out the gold alloy may contain silver. Herein, we report an interesting case of an old woman who has amalgam tattoo after dental restoration with gold alloy.