Heavy Metal Pigmentation
Heavy metal pigmentation occurs with exposure to various types of heavy metals such as arsenic, bismuth, platinum, lead, silver, copper, and mercury; it can be problematic in the body and may cause pigmented lesions in the soft tissues. Subjection to these metals through excessive ingestion, inhalation, or prolonged cutaneous exposure may result in pigments accumulating in the oral mucosa or in any cutaneous surface.
Argyria. Argyria is the slate-gray or bluish discoloration of the skin caused by the accumulation of silver salts in the tissues. Silver was often used in the treatment of the nose and sinuses. Several metals are seen clinically as pigmentations and line stains. Discontinuing exposure to the metal is paramount. The prognosis is good when exposure is discontinued and the body levels of the substance are not high.
Lead. Lead poisoning in children, or plumbism, has been a significant problem in past decades and is usually due to environmental causes such as chipping paint, putty, plaster, pesticides, and lead-lined pipes. Lead-line stain, sometimes referred to as Burtonian line, is often seen at the gingival margins when the lead proportion reaches certain levels. The common color of the line, often found in the premolar and molar gingiva, is blue, gray, or black.
Bismuth. Bismuth was used to treat syphilis and produces a thin blue-black line. Diascopy may be used to differentiate heavy metals from common gingivitis around the margins. The lead line will become more accentuated when a glass slide is placed over the tissue, and the gingivitis line (due to inflammatory causes) will disappear. Further testing to confirm lead accumulation or differentiation from other heavy metals is needed, with blood levels documented. Recent reports of macular pigmentation of the tongue were related to bismuth subsalicylate (Pepto-Bismol) as the suspected agent responsible for the black tongue in a patient .