Applied Dental Materials 2 Lecture 6 (Direct Filling Gold)

Front 1

In what year was gold jewelry being made in Sumerian, Babylonian, Assyrian and Egyption civilizations?

Back 1

3000-1293 BC

Front 2

What year, and by whom, was the first documented case of gold use as a restorative material?

Back 2

1483, Giovanni d' Arcoli

Front 3

In what year did Philip Pfaff use gold to cap dental pulp?

Back 3

1715-1767

Front 4

Gold leaf was used by ___ ___ in the U.S. as a restorative material in what year?

Back 4

1812

Front 5

Cohesive gold was introduced in the year ___ by Robert Arthur

Back 5

1855

Front 6

The following is true of gold

(least/most) noble of all metal
(easy/difficult) to tarnish
(soft/hard)
can be (cold/hot) welded at room temp
(low/high) thermal conductivity
(low/high) density

Back 6

most, difficult, soft, cold, high, high

Front 7

Direct filling gold is usually availably in __% purity

Back 7

99.99%

Front 8

T or F, direct filling gold is condensed directly into a prepared cavity

Back 8

T

Front 9

By what process do layers of gold adhere to each other when condensed?

Back 9

cold-welding

Front 10

Compaction (lowers/raises) strength of gold

Back 10

raises

Front 11

What is the mechanism by which compaction raises the strength of gold?

Back 11

strain-hardening (work-hardening)

Front 12

T or F, gold should never be contoured or polished in the mouth

Back 12

F

Front 13

Gold is:

technique (sensitive/insensitive)
(easy/difficult) to form a dense restoration

Back 13

sensitive, difficult

Front 14

Direct filling gold is recommended to restore:

Class I, usually (premolars/molars)

Class (II/III)

Class (IV/V)

(non-esthetic/esthetic)

(high/low) stress

Back 14

premolars, III, V, non-esthetic, low

Front 15

True or False, you want to avoid placing gold near other prosthetic materials such as partial denture clasps

Back 15

True

Front 16

What are 3 forms of direct filling gold? Give examples of each.

Back 16

preformed gold foil (gold leaf, fibrous gold)
electrolytic precipitate (mat gold, crystalline gold)
powdered gold (granular gold)

Front 17

What's the only direct gold filling material that is not 99.99% gold?

Back 17

Au-Ga electrolytic precipitate (contains 0.1% Ca)

Front 18

a 4x4 inch gold sheet weighting 4 grams that's 0.5micrometers thick would be No. __ gold foil

Back 18

4

Front 19

Electrolytic and powdered gold is made from No. __ foil

Back 19

3

Front 20

No. 4 gold can be rolled into ___ and ___

Back 20

ropes, cylinders

Front 21

Cylinders can be made from No. __ and __ (aside from No. 4)

Back 21

60, 90

Front 22

Preformed gold foil is typically used where?

Back 22

surface of restoration

Front 23

Platinized foil is made by (soaking/hammering) Pt foil between __ (#) layers of No. 4 gold or bonding layers of Pt and __ together by a process called ____

Back 23

hammering, 4, Au, cladding

Front 24

Pt does what to Au foil?

Back 24

increases hardness and wear resistance

Front 25

Gold foil free of contaminants is known as what?

Back 25

cohesive foil

Front 26

Gold foil is treated with ammonia for what reason?

Back 26

keep other impurities from forming on gold and to prevent premature cohesion

Front 27

What can happen if gold foil is not treated with volatile protective agents?

Back 27

noncohesive foil

Front 28

What is the process called where the volatile film is removed by heating? (known by 3 names)

Back 28

degrassing, desorption or heat treatment

Front 29

Heating of gold foil is accomplished over a flame of what gas or on an annealing plate at what temperature?

Back 29

alcohol, 650-700C

Front 30

Electroplating precipitate gold is a powder formed by electrolytic precipitation, shaped by sintering below melting pt of Au, which is ___ C

Back 30

1063

Front 31

Electrolytic precipitate has a typical ___ structure with crystals that are ___ mm long

Back 31

dendritic, 0.1

Front 32

Mat gold is available in strips, T or F

Back 32

T

Front 33

Mat gold is often preferred for what reasons?

Back 33

ease and efficiency of manipulation by which bulk of restoration may be formed

Front 34

Mat gold is (tightly/loosely) packed

Back 34

loosely

Front 35

Mat gold contains voids and is friable, T or F

Back 35

T

Front 36

Mat gold (is/is not) used on surface of restorations

Back 36

is not

Front 37

Mat foil is a sandwich of mat gold and No. __ foil, in strips

Back 37

3

Front 38

What component of Au-Ca electrolytic precipitate results in dispersion strengthening?

Back 38

0.1% Ca

Front 39

What is made by enclosed atomized or chemically precipitated Au powder in No. 3 gold foil?

Back 39

powdered gold

Front 40

Powered gold is made by enclosed atomized or chemically precipitated Au powder in No. 3 gold foil to form (square/irregular) shaped, pre-condensed (rods/pellets)

Back 40

irregular, pellets

Front 41

T or F, loose powder disintegrates when compacted

Back 41

T

Front 42

Powder is mixed with ___ to shape the pellet and then a covering of foil is used

Back 42

wax

Front 43

T or F, the wax border can be left behind in making powdered gold

Back 43

F, should be eliminated

Front 44

T or F, powdered gold is available in one size and shape

Back 44

F, cylindrical pellets in various diameters and lengths

Front 45

Decontamination of direct gold restorations occurs via ___ and is essential to ensure a (adhesive/cohesive) mass and to maximize the (chemical/physical) properties of the restoration

Back 45

desorption, cohesive, physical

Front 46

strength and hardness of the compacted gold vary depending upon the type of gold used and method of compaction, T or F

Back 46

T

Front 47

Properly condensed gold foil is (harder/softer) than softened type 1 cast gold alloy

Back 47

harder

Front 48

Between 100-800C, gold gets (softer/harder) as temperature increases

Back 48

harder