Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Restorative > Casting Alloys > Flashcards

Casting Alloys Flashcards

1
Q

What is an alloy?

A

an alloy is a mixture of one or more metallic elements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

T/F alloys have better qualities than the metal used alone

A 
T
Cost
Bicompatibility
Mechanical properties
Easy of casting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are some alloys used in dentistry?

A

Amalgam
Gold
SS
NiTi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

WHat are the three stages in alloy fabrication?

A

FAC

Forming
Amalgamtion
Casting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

WHat happen in the forming phase?

A

plastic deformation

hot and cold working eg extrusion, rolling, drawing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens in the amalgamtion phse?

A

blending mercury with other materials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens in the casting phase?

A

puring molten metal into mould

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What technqiues tdo we use for dental casting alloy?

A

lost wax technique

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the two groups of cating metal alloys?

A

Noble

Base Metal Casting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the two types of noble metal alloys?

A

Gold

Silver palladium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the three types of base metal casting alloys?

A

Titanium
Nickle Chromum
CoCr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

T/F Noble metals do not regtain luster in clean dry air?

A

F

they do

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are noble metals resisnt to?

A 
oxidation
tarnish
corrosion 
casting 
soldering
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the thre types of noble metals used?

A

platunum goeup
gold
silver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What metals are inside the platiunum group?

A 
platinum
iridum
osmim
ruthenium
rhodoim
palladium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

WHat are the properties of gold?

A

soft malleable and ductile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

T/F Gold has a relatively low strentgh>

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

When or not does gold tarnish?

A

gold does not tarnish in air or water at any temp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What type of oxidsing agnets can attcck gold?

A

very powerful ones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What acids is gold insoluble in?

A

nitric

sulphiric and hydrochloric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What acids is gold souble in?

A

when nitric and sulfuric acid is combined

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the effect of impurities on golds properties?

A

eg lead and mercury

they are detrimental

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

WHat are the mechanical propertes of pt?

A

touch malleable and ductile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How com,on is Pt used now?

A

rarely since too expensive and has been replaced by oaladium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
T.F Pt has a low corrosion resistance?
f | high
26
What is the metal poin of Pt compared to porcelain?
higher
27
Which noble metal is not used in its pure state in dentistry?
Palladium
28
WHat has Pd repalced?
Pt
29
What is the effect of Pd in silver>
helps prevent corrosion in mouth
30
What is the ffect of heating Pd improperly?
abosrobs H2 gas
31
What are the properties of Ag?
malleable and ductile
32
T/F Ag is harder than gold?
t
33
Which metal is the best known conductor of heat and elctricuty?
silver
34
What is the effect of clean dry air on silver?
none | not altered
35
T/F Silver tarnishes in the mouth?
T
36
Why does silver tarnish in the mouth?
combines with sulfur chlorine and phosphorus
37
What happens when silber is in its molten state?
it occludes large amounts of ocygen which then evolves when silver solidifeies creating pits and voids
38
Give examples of minor alloying elemnets?
Iridum | Ruthenium
39
What is the effect of ruthenium and iridium?
they are both grain refinfing
40
How much Ru and Ir are added to the metals?
50ppm 0.005% | which will increase grain number by 100
41
T/F Ir and Ru can increase alloy tensile strength?
T | by 30% !!!!!!
42
What effect does Ir and Ru have on hardness?
no effect
43
What is the effect of Ir and Ru on tarnish?
increases tarnish resistance
44
What is the effect of Ir and Ru on yiled streess?
sight increase
45
WHat is the problem with using gold in ots pire state?
it is too soft
46
What type of gold is used in fillings?
cohesive gold
47
What types of gold are there?
``` 4 types 1 soft 2 medium 3 hard 4 v hard ```
48
How does the gold content change from type 1 to 4?
it decreases
49
What are the two ways of measuring gold content in a ental alloy?
Karat | Finess
50
Karat measures what?
oarts of pure gold per 24
51
How much is 12K gold? | How much is 18K gold?
12=50% gold | 18=75%
52
What does finess measure?
parts of pure gold per 1000
53
WHen is finness usually used?
for measuring gold in solders
54
Whaty does a finess of 650 mean?
65% gold
55
What 5 metals are added to gold?
``` copper silver palladium platinum zinc ```
56
What is the pupose of copper in gold?
strengthening lowers MP tarnishes
57
What is the pupose of silver in gold?
slightly strengthening and conunteract coppers reddish tint
58
What is the purpse of Pt and Pd in gold?
increases Melting temp
59
What is the purpose of Zn in gold?
acts as a scavenger during casting and impoves catability
60
Which properties increase as you go from type 1 to type 4 gold?
hardness Mod elasticiy tensile strength propotional limit
61
Which properties decrease as you go from type 1 to type 4 gold?
Ductility | corrosion resistance
62
When is type 1 gold used?
inlays where they are well suported an no large masticaroy forces since it is v ductile, it can be burnshed and well adapted to margins
63
Where is type 2 gold used?
inlays | better than type 1 just more brittle
64
Where is type 3 gold used?
``` areas where less support from tooth and high opposing stress inlays onlays crown short span bridge ```
65
Where is type 4 gold used?
denture and long span bridg
66
What are low contet gold alloys?
contain less than 65% gold
67
What is the typical range of gold in low content gold alloys?
10-45%
68
Which type of golds 1,2,3,4 are low content gold most like?
3 and 4 but more brittle
69
What are silver palladium alloys?
xontain no or little gold
70
What are the components of Ag-Pd alloys?
Bulk silver 25% Pd Small: copper zinc indium occ. gold
71
What are base metal casting alloys?
contain no or little gold, Ag, Pt or Pd NiCr CoCr Ti and TiAlV
72
WHen are NiCr used?
crown and bridge
73
When are CoCr used?
dentire
74
Where are Ti used?
implant
75
Which two metals in the base metal casting alloys are interchangebel?
Ni and Co
76
What is the percentage of Ni or Co and Cr in base metal casting alloys?
60% Ni or Co | 30% Cr
77
What is the metal point of Co/Ni Cr alloys?
1300-1500
78
what is the purpose of adding Molybdenum to Co/Ni Cr alloys?
grain refining
79
What os the modulus of elasticity for Co/Ni Cr alloys?
250 GPa Gold is 70-100
80
What is teh Vickers Hardness for Co/Ni Cr alloys?
350-400 type 4 Gold is 250-300
81
WHat is the propeties of chromium and what perce tage is it added?
added at 25% tarnish and corroson resistance due to passivation
82
What happens if Cr is added at more than 30%?
difficulty casting and brittle
83
What percentage is Co and Ni added and what is the differnce when using Ni vs Co?
form the bulk 65-78% Ni alloys have: decreased Strngh, hardness, MOE fusion temps. Increaed ductulity and elongation
84
What are the minor alloying elements added and what is the pirpse?
They control the most of the physical properties Carbon: 0.1-0.5% increases strengthm hardness and brittleness, Beryllium: 0.5-2% decreases fusion temp and allows for electrolytc etching Mb: 3-6% increases strength hardness and elongation Al: 4-5% Froms Ni3Al precipiate which increases tensile and yiled strength

Restorative (45 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions