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Materials for Cast Restorations

Contributed by:

Andrea
SDH  PRCC, MS.
  1. The most corrosion resistant of all metals.

Gold

  1. 24 karat gold is too soft, so what is it mixed with to make it harder?

Alloys

  1. Noble metals are metals of:

 Highest quality.

  1. 2 noble metals used in dentistry are:

Palladium & platinum.

  1. 100% gold in karats is: 24 kt.
  1. 100% gold is 1000 fine. What would 50% gold be in fineness and karat?

12 kt. Or 500 fine.

  1. Gold foil:

24 kt, sheets, used for small restorations.

  1. The process of pouring a molten alloy into a mold to form a restoration: casting.
  1. Matching

Type I       C

 A. More complex inlays

Type II       A

B. 78% gold crown and bridge

Type III     B

C. Softest, 80% gold, simple inlays.

Type IV      D

D. Hardest, 75% gold, partials

 

  1. Matching

Gold  D

A. Tarnish easily, strength & hardness, lowers tarnish resistance.

Silver  A

B. Strength

Copper  E

C. Deoxidizing agent/oxygen scavenger, prevents porosity

Platinum   B

D.  Tarnish resistant, less toxic

Palladium  F

E. Strength & hardness, less biocompatible

Zinc   C

F. Strength, less toxic

 

  1. Connecting metals by fusion:

Soldering.

  1. Flux:

Used in soldering to prevent porosity.

  1. When porcelain is bonded to metal they must have similar:

 Coefficient of Thermal Expansion.

  1. A precious metal: Gold.
  1. A semi- precious: palladium.
  1. A non- precious metal: Nickel, chromium.
  1. Cobalt Chromium Alloys are seen in: Partial frameworks.
  1. Lost wax technique is used in: Casting metals
  1. Invest in lost wax technique: when stone is poured into cylinder.
  1. Sprue in lost wax technique: Holds wax model, rod, forms channel for molten gold.
  1. Burnout in lost wax technique: eliminating wax.

Disclaimer: These notes were copied and pasted from files sent to me by Andrea.  They have not been reviewed for errors. You are responsible for checking out the information to verify the accuracy. This site, Amy Nieves and Andrea are not responsible for typographical errors.

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