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Abstract
The amalgam tattoo is the most common extrinsic pigmented lesion of the oral mucosa and is generally located near areas where amalgam restorations were performed. Clinically, amalgam tattoos manifest as an asymptomatic macula, of bluish, grey or black colouring with no surrounding erythematous response. Generally, they are located on the gingiva or alveolar mucosa, and less frequently in the buccal mucosa and floor of mouth. Radiographs are indicated to confirm the presence of metallic particles in the oral tissues. The differential diagnosis of amalgam tattoo should be done with other pigmented lesions, such as melanocytic nevi, focal melanosis, physiologic pigmentation, vascular lesions, pigmentation caused by implanted exogenous materials and melanoma. Thus, criteria should be established to assess the best way to investigate this pigmented lesion and the need to perform a biopsy to provide an accurate diagnosis. In this paper, we report two cases in the elderly edentulous population with amalgam tattoos imitating other pigmented lesions that present distinct clinical behaviour and treatment and discuss the challenge of differential diagnosis.
Keywords: dental amalgam, differential diagnosis, melanoma, pigmentation disorders, stomatology
Introduction
Oral pigmented lesions can be the result of a variety of causes, both endogenous and exogenous, including malignant and benign aetiology. They could be grouped as being melanotic (originated from the melanocytes) and non-melanotic. The exogenous lesions are mainly caused by foreign-body implantation in the oral mucosa [1, 2].
Amalgam tattoos are the most common extrinsic lesion of oral mucosa, generally located near areas where amalgam restorations have been performed. The silver amalgam is a type of alloy whose composition includes silver, tin, copper and zinc, crushed in equal parts by weight mercury. Silver amalgams have been widely used as dental restorative material [2-4].
Accidental implantation of amalgam in the oral tissues can occur in several ways: 1. Abrasion or accidental laceration of the mucosa with a high-speed tool containing particles of amalgam, sometimes spreading the metal particles, which then penetrate the intact mucosa during the instrument's use; 2. Fragments of a fractured amalgam that lodge in the alveoli or under the periosteum at the time of extraction; 3. Deposition of an amalgam within a surgical wound during retrograde filling with this material after apicectomy. Apart from accidental deployment, the prolonged contact of...