Lichenoid amalgam reaction

What is a lichenoid amalgam reaction?

Lichenoid amalgam reaction, also known as oral amalgam-associated lichenoid reaction, is rare allergic reaction after long exposure to dental amalgam fillings.

Who has a lichenoid amalgam reaction?

Like oral lichen planus, it affects women more often than men, and is more common in middle age. It happens adjacent to an amalgam of dental filling.

Clinical features

Clinically and histologically, is indistinguishable from idiopathic oral lichen planus.

The clinical clues that may suggest this diagnosis are:

1. very close to a dental amalgam filling
2. located injury
3. asymmetric.

The buccal mucous membrane (inside the cheek) is the most common affected site, with the edge of the tongue being the next most common.

Oral lichenoid lesions have been classified into three groups according to the relationship with the amalgam filling:

• Group I: the lesion is limited to the area in direct contact with the amalgam filling
• Group II: lesion exceeds contact area
• Group III: the lesion does not show contact with an amalgam filling.

As with idiopathic oral lichen planus, there are four clinical patterns: lattice, erosive, atrophic and license plate-like, with the most commonly seen reticular pattern.

The injury can be asymptomatic or show symptoms such as pain or tenderness when eating hot or spicy foods.

How do you make the diagnostic

The diagnosis will be suspected clinically due to the close relationship between the lesion and a dental amalgam filling. However, idiopathic lichen planus can develop in sites of trauma like the rubbing of rough dental restorations. Signs of lichen planus elsewhere, including in the mouth, skin, nail and the scalp should be sought.

A biopsy of the injury will show the same histological features such as idiopathic oral lichen planus. Immunofluorescence can be done to exclude autoimmune diseases of the mouth, and again it is the same as for idiopathic oral lichen planus.

Patch Tests with amalgam and inorganic mercury salts will be positive more frequently in patients with a lichenoid amalgam reaction than in those with idiopathic oral lichen planus. However, a negative result does not exclude the diagnosis. Therefore, the role of this test in making the diagnosis is unclear.

The only diagnostic test is the response to replacing the amalgam filler with an alternative filler material. However, the effect of removing the amalgam cannot be predicted by biopsy. histology or patch test results.

Treatment

If the injury is symptomatic, it is recommended to replace the amalgam with an alternative filler material. In European studies, more than 90% of patients showed marked improvement or disappearance of the lesion after replacement of the padding, especially for Group I and tongue lesions. Complete removal was more likely to occur in Group I patients with a positive reaction to the amalgam patch test.

However, if the injury is not causing symptoms or if the patient has lichen planus of the skin, an annual checkup and the use of alternative fillings for future dental work is suggested.

In addition, the following treatments may be helpful:

1. powerful current steroids like clobetasol propionate
2. other topical treatments like tacrolimus
3. oral medications including oral steroids such as predniso (lo) ne.

No progression to oral Cancer An oral lichenoid lesion adjacent to the amalgam has been reported to date.

Proposed Mechanism

Lichenoid amalgam reaction appears to be delayed (type IV) cell-mediated contact hypersensitivity either mercury or another component of amalgam.