Gold (Bling Bling)

Question 1

Most noble, corrosion resistant, ductile, and malleable metal.

Answer 1

Gold

Question 2

Gold is too weak for dental restoration unless _____ are used

Answer 2

Other alloying elements

Question 3

Gold can be etched by ____

Answer 3

Aqua Regia

Question 4

Expresses the relative amount of gold in an alloy.

How much is pure gold?

Answer 4

Carat (k)

24k

Question 5

Percentage of gold content multiplied by a factor of 10 (75 percent is 750). Used for specification of dental solders

Answer 5

Fineness

Question 6

The current standard for dental casting alloys is ____

Answer 6

ISO 22674

Question 7

ISO Standard 22764 Mechanical Property requirements:

Answer 7

0.2% offset yield strength minimum

Minimum percentage elongation after fracture

Question 8

Additional alloy selection factors:

Answer 8

1. Cost of metal per pennyweight
2. Burnishability
3. Solderability
4. Experience of dental lab

Question 9

ISO Type ___ Alloy: Very low stress-bearing restorations (small veneered one-surface inlays, veneered crowns; also metallic materials for metal-ceramic crowns produced by electroforming/sintering)

Answer 9

Type 0

Question 10

ISO Type ___ Alloy: Single-tooth fixed restorations (crowns/inlays without restriction on number of surfaces)

Answer 10

Type 2

Question 11

ISO Type ___ Alloy: Appliances requiring combination of high stiffness and strength (thin RPDs, parts with thin cross-sections, clasps)

Answer 11

Type 5

Question 12

ISO Type ___ Alloy- low stress bearing single tooth restorations (veneered or unveneered one-surface inlays, veneered crowns)

Answer 12

Type 1

Question 13

ISO Type ___ Alloy- Multiple-unit fixed restoration (bridges)

Answer 13

Type 3

Question 14

ISO Type ___ Alloy: Thin sections subjected to very high forces (RPDs, clasps, thin veneered crowns, etc.)

Answer 14

Type 4

Question 15

ISO Types ___ and ___ alloys are usually used in dental schools

Answer 15

2 and 3

Question 16

Principal element for hardening and strengthening

Answer 16

Copper

Question 17

Counteracts effect of copper on color and substitutes economically for gold w/out degrading mechanical properties

Answer 17

Silver

Question 18

Provide tarnish and corrosion resistance as well as strengthening (used sparingly because of raised alloy melting temps)

Answer 18

Platinum and Palladium

Question 19

Provides ductility, tarnish, and corrosion resistance to alloy

Answer 19

Gold

Question 20

Oxygen scavenger during melting to minimize oxidation of other elements; considered to improve castability or fluidity of molten alloy

Answer 20

Zinc

Question 21

Small amounts of indium and gallium may be prevalent in alloy to provide ____ and ____. Very small amounts of iridium are generally incoporated to provide desired _____.

Answer 21

Hardening
Strengthening

Grain Refinement (small grain size- improves mechanical properties, uniformity in microstructure, corrosion resistance)

Question 22

Characteristic trends on going from ISO Type 1 to 5 casting alloys:

Answer 22

1. More yield strength/hardness
2. Less ductility
3. Less gold
4. Less ease of adjustment/burnishability (for casting)
5. Lower melting temp

Question 23

Slow cooling of alloy results in ____ material.

Quenching of alloy results in ____ material.

Answer 23

Harder

Softer

(Needs time for ordering transformation)

Question 24

The special _____ containing gold alloy age-hardens rapidly at room temperature.

Answer 24

Gallium