gold foil

gold foil,

pure gold that has been rolled and beaten into a very thin sheet, used for making foil pellets, which are a direct dental restorative material. The main types of gold foil are cohesive, semicohesive, and noncohesive.

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foil,

n a very thin, flexible sheet of metal, usually gold, platinum, or tin.

foil, adhesive,

n a tin foil that is covered on one side with powdered gum arabic or karaya gum.

foil assistant,

n See foil holder.

foil, cohesive gold,

n a gold foil that has been annealed or had a surface so completely pure so that it will cohere or weld at room temperature.

foil, corrugated gold,

n a gold foil made by burning gold foil sheets between paper in the absence of air.

foil cylinder,

n a cylinder of gold foil formed by repeatedly folding a sheet of foil into a narrow ribbon, which is then rolled into cylindrical form.

foil, gold (fibrous gold),

n pure gold that has been rolled and beaten from ingots into a very thin sheet. Thickness usually varies from 1/40,000 inch (No. 2 foil) to 1/20,000 inch (No. 4 foil). Classified as cohesive, semicohesive, or noncohesive. One of the oldest restorative materials, the most permanent if used properly, and the yardstick by which all others are measured. It is compacted or condensed into a retentive cavity form piece by piece, using this metal's property of cold welding.

foil holder (foil assistant),

n an instrument used to retain a foil pellet in place while it is being condensed or to retain a bulk of gold while additions to it are made.

foil, noncohesive gold,

n a gold foil that will not cohere at room temperature because of the presence on its surface of a protecting or contaminating coating. If the coating is a volatile substance, such as ammonia, the foil may be rendered cohesive by heating or annealing it to remove the protection.

foil passer (foil carrier),

n a pointed or forked instrument used to carry pellets of gold foil through an annealing flame or from the annealing tray to the prepared cavity for compaction.

foil pellet,

n See pellet, foil.

foil, platinized gold

(plat´nīzd),
n a form rolled or hammered from a “sandwich” made of platinum placed between two sheets of gold; used in portions of foil restorations where greater hardness is desired.

foil, platinum,

n pure platinum rolled into extremely thin sheets. A precious-metal foil whose high fusing point makes it suitable as a matrix for various soldering procedures; also suitable for providing the internal form of porcelain restorations during fabrication.

foil, tin,

n a base-metal foil used as a separating material, or protective covering (e.g., between the cast and denture base material during flasking and curing procedures).

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gold,

n a precious or noble metal; yellow, malleable, ductible, nonrusting; much used in dentistry in pure and alloyed forms.

Exophthalmic goiter.

gold alloys,

n.pl an alloy that contains gold; usually alloyed with copper, silver, platinum, palladium, and zinc. The alloying of gold enhances certain properties such as hardness, or creates a lower melting point for gold solder.

gold, cohesive,

n gold usually manufactured in thin sheets of foil, that has been treated to cause it to cohere, or stick together. This allows it to be easily formed into a variety of shapes.

gold compound,

n a drug containing gold salts, usually administered with other drugs in the treatment of rheumatoid arthritis. Various radioisotopes of gold have been used in diagnostic radiology and in the radiologic treatment of certain malignant neoplastic diseases.

gold, crystal,

n See gold, mat.

gold, fibrous,

n See foil, gold.

gold file,

n See file, gold.

gold foil,

n See foil, gold.

gold foil cylinder,

n See foil cylinder.

gold foil pellet,

n See pellet, foil.

n 1. an alloy, principally gold, used for cast restorations. Desired physical properties may be obtained by selecting those with varying ingredients and/or proportions. Acceptable alloys are classified by the American Dental Association (ADA) specifications according to Brinell hardness: Type A soft, Brinell 40 to 75; Type B medium, Brinell 70 to 100; Type C hard, Brinell 90 to 140.
n 2. an intracoronal cast restoration of gold alloy fabricated outside the oral cavity and cemented into the prepared cavity.

gold knife,

n See knife, gold.

gold, mat,

n (crystal gold, sponge gold) a noncohesive form of pure gold prepared by electrodeposition. Sometimes used in the base of restorations and then veneered or overlaid with cohesive foil.

gold, powdered,

n the fine granules of pure gold, formed by atomizing the molten metal or by chemical precipitation. For clinical use, powdered gold is available either as clusters of the granules or as pellets of the powder contained in an envelope of gold foil.

gold saw,

n See saw, gold.

gold sodium thiosulfate,

n an antirheumatic used in the treatment of rheumatoid arthritis.

gold, sponge,

n See gold, mat.

gold, white,

n a gold alloy with a high palladium content. It has a higher fusion range, lower ductility, and greater hardness than a yellow gold alloy.