2-16. CASTING GOLD ALLOY
a. General. Restorations made with gold foil do not exhibit as much overall
strength and resilience as do restorations made with gold alloys. Casting gold alloy is
used in the fabrication of various types and classes of restorations. It is alloyed and
made into ingots suitable for melting and casting into molds for the restorations.
b. Four Types of Casting Gold Alloys.
(1)
Soft. For inlays not subjected to stress.
(2)
Medium. For ordinary inlay work.
(3)
Hard. For full crowns, three-quarter crowns, and retainers.
(4)
Extra hard. For saddles, clasps, and one-piece cast partial dentures.
c. Usage. Casting gold alloys can be whitened (white gold) by adding
palladium, platinum, or silver. Casting gold alloy is also used for crowns and abutments
requiring great strength and hardness.
2-17. GOLD ALLOY SOLDER
Gold alloy solder is used for joining the parts of fixed partial dentures, for building
up or forming restorations, and for gold repairs. Soldering is the process of joining
metals by means of a solder or a lower fusing metal.
2-18. WROUGHT GOLD
Wrought gold is used for the construction of clasps and orthodontic appliances.
2-19. GOLD PLATE
Gold plate is used less often than casting gold alloy, gold alloy solder, or wrought
gold. It is used in the fabrication of some types of crowns and often used in repair
procedures.
2-20. NONPRECIOUS ALLOYS
Nonprecious alloys were developed as an alternative to the expensive precious
metal alloys. They are used primarily in the fabrication of ceramometal restorations.
These alloys are composed chiefly of chromium, nickel, and molybdenum.
MD0502
2-8
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