Dictionary of Allergies .. Dental amalgam

Dental amalgam

The most frequently used metallic compound is dental amalgam which mainly contains mercury and silver. Allergy to amalgam is very rare; billions of fillings are made from amalgam but only a few dozen cases of allergy have been reported. Many people with mercury hypersensitivity did not react to amalgam fillings. The mercury component is the more frequently allergenic, but the complex amalgam product itself may also trigger reactions, by silver, or by other amalgam components such as copper or zinc. Skin can be affected in severe cases (rush on face and limbs) followed by a progression to dermatitis.[1]. Eczematous eruptions may be produced through topical contact with mercury and by systemic absorption in mercury sensitive individuals. Mercury is considered a weak sensitiser and contact with mercury salts such as chloride or ammonium chloride may cause hypersensitivity leading to contact dermatitis or Coomb's Type IV hypersensitivity reactions. The typical manifestation is an urticarial or erythematous rash, and pruritus on the face and flexural aspects of limbs, followed by progression to dermatitis. True allergy to mercury is rare but is more common in females[2].

Kal BI, et al (2008) described a case of immediate hypersensitivity reaction associated with the mercury component of amalgam restorations. The release of mercury induced an acute reaction which resulted in erythematous lesions, severe burning and itchy sensation and difficulty in breathing. Skin patch test results indicated a very strong positive reaction to mercury. Amalgam restorations were replaced with composite filling material [3].   (See Mercury).

References

1. Duxbury, A.J. et al: Br Dent. J. 152, 344 (1982).

2. Bains VK, Loomba K, Loomba A, Bains R. Mercury sensitisation: review, relevance and a clinical report. Br Dent J. 2008 Oct 11;205(7):373-8. Comment in: Br Dent J. 2009 Jan 24;206(2):55-6.

3. Kal BI, Evcin O, Dundar N, Tezel H, Unal I. An unusual case of immediate hypersensitivity reaction associated with an amalgam restoration. Br Dent J. 2008 Nov 22;205(10):547-50.