Biomaterial Database

Recent developments in alloys for dental amalgams: their properties and proper use. 1976

K D Jorgensen

Since the development more than ten years ago of a new type of amalgam alloy that will react with mercury without forming the unfavourable gamma2 (Sn7-8Hg) phase, several new alloy brands with a similar reaction pattern have been presented. This new generation of amalgam alloy is called non-gamma2 alloy as distinct from the conventional alloys. Three of the new alloys studied contain approximately three volume percent gamma2 and should be classified as modified concentional amalgams. The non-gamma2 amalgams may be characterized in the following way: (1) instead of gamma2 they contain a reaction product of copper and tin (Cu6Sn5), the so-called eta1 phase. (2) They are significantly more resistant to corrosion than the conventional amalgams but do in time produce sufficient solid corrosion products to seal the micro-fissures between filling and cavity walls. (3) When corroding, they do not release metallic mercury, and the solid corrosion products formed and precipitated on the free surface of the fillings seem relatively little resistant to the organic acids of the plaque. (4) Most of them have relatively low creep and tensile strength, but high compressive strength. (5) Clinically the non-gamma2 amalgams are remarkable for superior marginal integrity and, seemingly, also for improved persistence of surface lustre.

UI	MeSH Term	Description	Entries
D008628	Mercury	A silver metallic element that exists as a liquid at room temperature. It has the atomic symbol Hg (from hydrargyrum, liquid silver), atomic number 80, and atomic weight 200.59. Mercury is used in many industrial applications and its salts have been employed therapeutically as purgatives, antisyphilitics, disinfectants, and astringents. It can be absorbed through the skin and mucous membranes which leads to MERCURY POISONING. Because of its toxicity, the clinical use of mercury and mercurials is diminishing.
D003300	Copper	A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.	Copper-63,Copper 63
D003343	Corrosion	The gradual destruction of a metal or alloy due to oxidation or action of a chemical agent. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Corrosions
D003722	Dental Alloys	A mixture of metallic elements or compounds with other metallic or metalloid elements in varying proportions for use in restorative or prosthetic dentistry.	Alloy, Dental,Alloys, Dental,Dental Alloy
D003723	Dental Amalgam	An alloy used in restorative dentistry that contains mercury, silver, tin, copper, and possibly zinc.	Amalgam, Dental,Amalgams, Dental,Dental Amalgams
D004570	Electrogalvanism, Intraoral	Chemical reaction that occurs when saliva comes into contact with the metals in dental fillings. This reaction can send electric currents through the brain causing negative symptoms.	Galvanism, Oral,Electrogalvanisms, Intraoral,Galvanisms, Oral,Intraoral Electrogalvanism,Intraoral Electrogalvanisms,Oral Galvanism,Oral Galvanisms
D013314	Stress, Mechanical	A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.	Mechanical Stress,Mechanical Stresses,Stresses, Mechanical
D013718	Tensile Strength	The maximum stress a material subjected to a stretching load can withstand without tearing. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed, p2001)	Strength, Tensile,Strengths, Tensile,Tensile Strengths
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor
D014001	Tin	A trace element that is required in bone formation. It has the atomic symbol Sn, atomic number 50, and atomic weight 118.71.	Stannum

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