Applied Dental Materials 2 Lecture 3 (Alloys 2)

Front 1

The following alloys are considered (HN/N/PB) alloys:

Fe-Cr
Co-Cr
Ni-Cr
Ni-Cr-Be
Ni-Co-Cr
Ti-6Al-4V
Ti-6Al-Nb

Back 1

Predominantly Base Metal (PB)

Front 2

Ti is a base metal ___ and not an alloy

Back 2

element

Front 3

CP Ti stands for ____

Back 3

commercially pure Ti (Titanium)

Front 4

Ti is the (most/least) biocompatible metal

Back 4

most

Front 5

Ti is used to fabricate what 4 types of dental restorations?

Back 5

all-metal
metal-ceramic
implants
RPD framework

Front 6

CP Ti is available in how many grades?

Back 6

5

Front 7

The 5 grades of CP Ti are based in the concentrations of ___ and ___

Back 7

O2 and Fe

Front 8

What is the range of O2 for CP Ti?

Back 8

0.18-0.40 wt%

Front 9

What is the range of Fe for CP Ti?

Back 9

0.2-0.5 wt%

Front 10

What three elements, other than Oxygen and Iron are also present in CP Ti?

Back 10

N2, C, H2

Front 11

What are the wt% of N, C and H2 in CP Ti?

Back 11

N = 0.03-0.05
C = 0.1
H2 = 0.02

Front 12

Grade __ is the purest and softest CP Ti

Back 12

1

Front 13

What are the 5 grade numbers of CP Ti?

Back 13

1, 2, 3, 4, 7

Front 14

Ti has (high/low) MP and (high/low) hardness

Back 14

high, high

Front 15

True or false, Ti requires special arc-melting equipment

Back 15

True

Front 16

Ti is (very/not very) resistant to sag formation and has a (high/low) CTE

Back 16

very, low

Front 17

Ti alloys have properties (better/worse) than CP Ti and slowly release what two elements?

Back 17

better, Al, V

Front 18

What is the term for the formation of protective film on the surface of a metal by a reactive element?

Back 18

passivation

Front 19

passivation is the formation of a protective film on the surface of a metal by a ___ element

Back 19

reactive

Front 20

What are three examples of "reactive elements" in passivation?

Back 20

Ti, Al, Cr

Front 21

PR alloys containing > or = to __ wt% Cr form a NONporous layer of Cr2O3 on the surfaces (before/after) exposure to atmospheric O2

Back 21

12, after

Front 22

In passivation, the oxide forms a (pore/barrier) to the flow of O2 and metal ions, preventing further oxidation and protection from corrosion

Back 22

barrier

Front 23

Modulus of elasticity is important in ___ ___ alloys because it determines how thick the different parts of the framework must be to resist ____

Back 23

denture alloys, deflection

Front 24

PB alloys, except __, are (2/4/10) times as rigid as type IV gold

Back 24

Ti, 2

Front 25

True or false, PB alloys can afford more resistance than the same thickness of Type IV gold

Back 25

True

Front 26

What happens to the modulus of elasticity of an alloy AFTER heat treatment?

Back 26

Nothing! It's only slightly affected... known as "structure-insensitive"

Front 27

PB alloys:

1. (harder/softer) than HN and N
2. (weaker/stronger) than HN and N
3. have (low/high) hardness

Note: The exception to 1 and 2 would be Ti

Back 27

harder, stronger, high

Front 28

PB alloys are (easy/hard) to polish. Why?

Back 28

hard, they have high hardness

Front 29

True or False, PB alloys can be hardened further by heat treatment

Back 29

False! This does not work!

Front 30

If Type IV gold is heat treated, it can become harder, up to __% less hardness than PB

Back 30

30

Front 31

PB alloys have (low/high) elongation values which makes them (hard/easy) to burnish

Back 31

low, hard

Front 32

which has a HIGHER specific gravity, Gold or PB?

Back 32

Gold

Front 33

HN alloys are how much denser than PB?

Back 33

twice

HN = 18.4g/cm^3
PB = 8.0 g/cm^3

Front 34

If you were going to make the same casting from HN and PB, which would require a larger amount of material by weight?

Back 34

HN

Front 35

HN and N are how much more expensive (per oz) than PB?

Back 35

thirty or more times as costly (wow...)

Front 36

(HN/N/PB) have high MP and require special treatment, investment, and finishing

Back 36

PB

Front 37

Cost of an alloys is usually presented as cost/____

Back 37

volume

Front 38

To calculate cost of an alloy, you must include the ___ and price per ounce

Back 38

density

Front 39

The difference in cost of a HN and PB alloy can amount to a factor of __ (#)

Back 39

80

Front 40

True or false, in calculating cost comparison, density is irrelevant as long as you know the cost/ounce

Back 40

False! you need density!

Front 41

ADA spec # __ limits the content of what element to only 2% in PB alloys?

Back 41

14, Be (Beryllium)

Front 42

Why is Be included in No-Cr alloys?

Back 42

improves the quality of the oxide layer

Front 43

The oxide layer is essential for bond formation to what material?

Back 43

porcelain

Front 44

Be in Ni-Cr enhances the castability of the alloy in concentrations < or = to __ wt%

Back 44

1.8

Front 45

Which can be casted into more intricate designs and finer detail, PB or Au alloys?

Back 45

PB

Front 46

What metal is considered the more biocompatible of all metals?

Back 46

Ti

Front 47

What two metals do some PB alloys contain that are considered potential allergens? (Hint: NOT in HN or N)

Back 47

Ni and Be

Front 48

Allergy to ___ (metal) is the most commonly encountered metal allergen and should be avoided for patients with known __-contact hypersensitivity

Back 48

Nickel, Ni

Front 49

Who is most at risk to the carcinogenic effects of Ni?

patients
dentist
dental techs
hygienists
assistants

Back 49

dental techs (exposure to Ni dust)

Front 50

What is the OSHA limit for Ni? (concentration/hour)

Back 50

15 micrograms/m^3 for a 10 hour exposure

Front 51

Some Ni-Cr contain __ to reduce fusion temp, improve casting, and refine grain structure

Back 51

Be

Front 52

Be has been shown to cause a chronic, inflammatory disease of the ___ known as berylliosis

Back 52

lung

Front 53

True or False, the body excretes Be within 1 week

Back 53

False, according to the lecture notes, the body CANNOT excrete it

Front 54

The presence of Be dust may be encountered after __ or ___ (procedures)

Back 54

melting, grinding

Front 55

Be alloys with < or = to 3% Be are tolerated to what extent compared to alloys without it?

Back 55

About the same

Front 56

True or false, Be containing alloys have proven to have devastating long term effects in dentists and patients, even at concentrations <3%

Back 56

False, no risk as long as proper ventilation is maintained in the operatory

Front 57

When working with Be containing alloys, the dentist needs to insure that ___ is close by

cotton products
HVE
Dixie, your assistant
A gumby
A herd of honey badgers

Back 57

HVE

Front 58

What is the OSHA limit for Be? (concentration/time)

Back 58

2 micrograms/m^3 for an 8-hour exposure

Front 59

List the 3 alloys currently used at OUCOD... good luck...

Back 59

1. Argebond 80 (N alloy) for MCR
2. Argenco 58 (HN alloy) for all-metal restorations
3. Argenco 42 (N alloy) for cast dowels

Front 60

List 5 alternative technologies to cast metal technology

Back 60

metal foil
CAD/CAM
Copy milling
electroforming
new technologies