Dental Amalgam - Restoration Material.

Dental amalgam is the most commonly used dental restorative material used for dental fillings. First introduced in France in the early 19th century, it contains a mixture of mercury with at least one other metal. Amalgam has been the restorative method of choice for many years due to its low cost, ease of application, strength, durability, and bacteriostatic effects. Factors that have led to recent decline in use are a lingering concern about detrimental health effects, aesthetics, and environmental pollution. The health issue concerns the known toxic affects of mercury and whether these are present in the amounts released from the amalgam. The aesthetic issue is because the metallic colour does not blend with the natural tooth colour. This is especially a concern when used on front teeth, but it can be addressed using alternative dental materials. The environmental concerns are regarding mercury emissions during preparation and from waste amalgam upon cremation of deceased individuals.

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Dental Amalgam Filling


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Dental Amalgam filling of 1^st Molar


Composition:

Currently, dental amalgams are composed of 43% to 54% by weight of mercury and the remaining powder is made up of mainly silver (~20-35%) and some tin, copper (~10%), and zinc (~2%).

Dental Amalgam - Chemistry

An amalgam is a substance formed by the reaction of mercury with another metal. Almost all metals can form amalgams with mercury, notable exceptions being iron and platinum. Silver-mercury amalgams are important in dentistry, and gold-mercury amalgam is used in the extraction of gold from ore.

The origin of the word amalgam is from the Medieval Latin amalgama, "alloy of mercury (esp. with gold or silver)," perhaps an alteration of L. malagma "poultice, plaster," probably from Arabic al-malgham "an emollient poultice or unguent for sores (especially warm)", perhaps from Greek malagma "softening substance," from malassein "to soften" from malakos "soft".

Dental Amalgam:

Dentistry has used alloys of mercury with metals such as silver, copper, indium, tin and zinc.

Classification of Caries Lessions - By G.V. Black

Greene Vardiman Black (1836–1915), commonly known as G.V. Black, is known as one of the founders of modern dentistry in the United States.

He researched many important topics to dentistry, including the best composition for dental amalgams and the cause of dental fluorosis. One of his many inventions was a foot-driven dental drill. Black was the first to use nitrous oxide for "extracting teeth without pain." He is also known for his principles of tooth preparations, in which he outlines the proper methods to prepare teeth for fillings. The phrase, "extension for prevention," is still famous in the dental community today and represents Black's idea that dentists should incorporate more grooves and pits than those currently exhibiting decay as a preventive measure against those grooves and pits developing tooth decay in the future.

Further, he organized 'Black's Classification of Caries Lesions' which is still in use today. Since that time, only one more category has been added to his classification system.

Black's Classification of Caries Lesions:

* Class I: Caries affecting pit and fissure, on occlusal, buccal, and lingual surfaces of posterior teeth, and Lingual of anterior teeth.