Amalgam tattoo is a grey, blue or black area of discoloration on the

mucous membranes A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is ...

of the mouth, typically on the gums of the lower jaw. It is a healthcare caused

lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classif ...

, due to entry of

dental amalgam Dental amalgam is a liquid mercury and metal alloy mixture used in dentistry to fill cavities caused by tooth decay. Low-copper amalgam commonly consists of mercury (50%), silver (~22–32%), tin (~14%), zinc (~8%) and other trace metals ...

into the soft tissues. It is common, painless, and

benign Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...

, but it can be mistaken for

melanoma Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye ( ...

Signs and symptoms

Amalgam tattoo usually occurs on the mandibular gingiva, often in an area in which an apicoectomy ("root-end filling") with amalgam was carried out. After the gingiva, the

alveolar mucosa The oral mucosa is the mucous membrane lining the inside of the mouth. It comprises stratified squamous epithelium, termed "oral epithelium", and an underlying connective tissue termed '' lamina propria''. The oral cavity has sometimes been des ...

and the buccal mucosa are the next most common sites, although any mucosal site in the mouth is possible. It is painless, and appears as a blue-black or grey discolored macule on the surface of the mucosa. The borders of the tattoo are variable, and may be well defined, irregular or diffuse.

Causes

Amalgam tattoo is caused by implantation of amalgam into the tissues. It may occur in several ways: * During placement of an amalgam filling, e.g. if abrasions on the mucosa are present which allow entry of amalgam dust * Shortly after placement of an amalgam filling, e.g. amalgam particles can contaminate

dental floss Dental floss is a cord of thin filaments used in interdental cleaning to remove food and dental plaque from between teeth or places a toothbrush has difficulty reaching or is unable to reach. Its regular use as part of oral cleaning is designed ...

and lead to linear amalgam tattoos in between the teeth, especially if flossing is carried out immediately after placement of an amalgam filling with a mesial or distal aspect * Polishing of an amalgam filling * The pressure from high speed turbine dental drills can be enough to force amalgam particles into soft tissue, as may occur when an old amalgam filling is being removed * When a tooth with an amalgam filling is extracted, e.g. broken bits of amalgam filling falling into an extraction socket unnoticed * When an amalgam filling is placed in the same appointment as a tooth extracted, as may occur in " quadrant dentistry" * Apicectomies are common causes of amalgam tattoo, since the amalgam is being placed inside the alveolus and the soft tissues are replaced on top Over time, the amalgam particles embedded in the soft tissues corrode.

Macrophage Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer ce ...

s take up the exogenous particles, and the silver in amalgam leads to staining of

collagen fiber Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the who ...

s. A similar appearance can be caused by implantation of

graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on la ...

(e.g. from pencil leads), and is sometimes termed a ''graphite tattoo'', although this is less common than tattooing with amalgam.

Diagnosis

The diagnosis is clinical. Amalgam tattoo can be distinguished from other causes of localized oral pigmentation because it does not change significantly in size or color, although it may appear to slowly enlarge for several months after the initial implantation of the metal particles. Some amalgam tattoos appear radio-opaque on radiographs (i.e. they show up on x-rays), although in many cases, amalgam tattoos have no radiographic features since the responsible particle(s) of amalgam are very small even though clinically the area of discolored mucosa is much larger. If necessary, the diagnosis can be confirmed

histologically Histology, also known as microscopic anatomy or microanatomy, is the branch of biology which studies the microscopic anatomy of biological tissues. Histology is the microscopic counterpart to gross anatomy, which looks at larger structures vis ...

by excisional

biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a dise ...

, which excludes

nevi Nevus (plural nevi) is a nonspecific medical term for a visible, circumscribed, chronic lesion of the skin or mucosa. The term originates from ''nævus'', which is Latin for "birthmark"; however, a nevus can be either congenital (present at bir ...

and

s. If a biopsy is taken, the histopathologic appearance is: * Pigmented fragments of metal within connective tissue * Staining of reticulin fibers with silver salts * A scattered arrangement of large, dark, solid fragments or a fine, black or dark brown granules * Large particles may be surrounded by chronically inflamed fibrous tissue * Smaller particles surrounded by more significant inflammation, which may be granulomatous or a mixture of lymphocytes and plasma cells

Prevention

Theoretically, routine use of a

dental dam A dental dam or rubber dam is a thin, square sheet, usually latex or nitrile, used in dentistry to isolate the operative site (one or more teeth) from the rest of the mouth. Sometimes termed "Kofferdam" (from German), it was designed in the Un ...

during dental procedures which involve amalgam should reduce the risk of amalgam tattoo.

Treatment

No treatment is required since the lesion is entirely benign. Some suggest that amalgam tattoos are best surgically excised so as to ensure the lesion does not represent a melanoma. Others say that excision should only be carried out if there is any doubt over the diagnosis, and that amalgam tattoos are managed by simple reassurance about the nature of the lesion. For example, if radio-opaque particles are demonstrated on the x-ray, biopsy is unnecessary.

Epidemiology

Amalgam tattoo is found in up to 1% of people in the general population. It is the most common cause of solitary or focal pigmentation of the oral mucosa.

Notes

References

External links

{{Oral pathology Oral mucosal pathology