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60 Cards in this Set
- Front
- Back
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 |
Predominantly Base Metal (PB)
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Ti is a base metal ___ and not an alloy
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element
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CP Ti stands for ____
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commercially pure Ti (Titanium)
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Ti is the (most/least) biocompatible metal
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most
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Ti is used to fabricate what 4 types of dental restorations?
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all-metal
metal-ceramic implants RPD framework |
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CP Ti is available in how many grades?
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5
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The 5 grades of CP Ti are based in the concentrations of ___ and ___
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O2 and Fe
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What is the range of O2 for CP Ti?
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0.18-0.40 wt%
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What is the range of Fe for CP Ti?
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0.2-0.5 wt%
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What three elements, other than Oxygen and Iron are also present in CP Ti?
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N2, C, H2
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What are the wt% of N, C and H2 in CP Ti?
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N = 0.03-0.05
C = 0.1 H2 = 0.02 |
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Grade __ is the purest and softest CP Ti
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1
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What are the 5 grade numbers of CP Ti?
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1, 2, 3, 4, 7
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Ti has (high/low) MP and (high/low) hardness
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high, high
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True or false, Ti requires special arc-melting equipment
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True
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Ti is (very/not very) resistant to sag formation and has a (high/low) CTE
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very, low
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Ti alloys have properties (better/worse) than CP Ti and slowly release what two elements?
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better, Al, V
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What is the term for the formation of protective film on the surface of a metal by a reactive element?
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passivation
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passivation is the formation of a protective film on the surface of a metal by a ___ element
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reactive
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What are three examples of "reactive elements" in passivation?
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Ti, Al, Cr
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PR alloys containing > or = to __ wt% Cr form a NONporous layer of Cr2O3 on the surfaces (before/after) exposure to atmospheric O2
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12, after
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In passivation, the oxide forms a (pore/barrier) to the flow of O2 and metal ions, preventing further oxidation and protection from corrosion
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barrier
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Modulus of elasticity is important in ___ ___ alloys because it determines how thick the different parts of the framework must be to resist ____
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denture alloys, deflection
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PB alloys, except __, are (2/4/10) times as rigid as type IV gold
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Ti, 2
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True or false, PB alloys can afford more resistance than the same thickness of Type IV gold
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True
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What happens to the modulus of elasticity of an alloy AFTER heat treatment?
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Nothing! It's only slightly affected... known as "structure-insensitive"
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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 |
harder, stronger, high
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PB alloys are (easy/hard) to polish. Why?
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hard, they have high hardness
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True or False, PB alloys can be hardened further by heat treatment
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False! This does not work!
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If Type IV gold is heat treated, it can become harder, up to __% less hardness than PB
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30
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PB alloys have (low/high) elongation values which makes them (hard/easy) to burnish
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low, hard
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which has a HIGHER specific gravity, Gold or PB?
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Gold
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HN alloys are how much denser than PB?
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twice
HN = 18.4g/cm^3 PB = 8.0 g/cm^3 |
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If you were going to make the same casting from HN and PB, which would require a larger amount of material by weight?
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HN
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HN and N are how much more expensive (per oz) than PB?
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thirty or more times as costly (wow...)
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(HN/N/PB) have high MP and require special treatment, investment, and finishing
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PB
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Cost of an alloys is usually presented as cost/____
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volume
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To calculate cost of an alloy, you must include the ___ and price per ounce
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density
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The difference in cost of a HN and PB alloy can amount to a factor of __ (#)
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80
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True or false, in calculating cost comparison, density is irrelevant as long as you know the cost/ounce
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False! you need density!
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ADA spec # __ limits the content of what element to only 2% in PB alloys?
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14, Be (Beryllium)
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Why is Be included in No-Cr alloys?
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improves the quality of the oxide layer
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The oxide layer is essential for bond formation to what material?
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porcelain
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Be in Ni-Cr enhances the castability of the alloy in concentrations < or = to __ wt%
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1.8
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Which can be casted into more intricate designs and finer detail, PB or Au alloys?
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PB
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What metal is considered the more biocompatible of all metals?
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Ti
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What two metals do some PB alloys contain that are considered potential allergens? (Hint: NOT in HN or N)
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Ni and Be
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Allergy to ___ (metal) is the most commonly encountered metal allergen and should be avoided for patients with known __-contact hypersensitivity
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Nickel, Ni
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Who is most at risk to the carcinogenic effects of Ni?
patients dentist dental techs hygienists assistants |
dental techs (exposure to Ni dust)
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What is the OSHA limit for Ni? (concentration/hour)
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15 micrograms/m^3 for a 10 hour exposure
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Some Ni-Cr contain __ to reduce fusion temp, improve casting, and refine grain structure
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Be
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Be has been shown to cause a chronic, inflammatory disease of the ___ known as berylliosis
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lung
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True or False, the body excretes Be within 1 week
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False, according to the lecture notes, the body CANNOT excrete it
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The presence of Be dust may be encountered after __ or ___ (procedures)
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melting, grinding
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Be alloys with < or = to 3% Be are tolerated to what extent compared to alloys without it?
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About the same
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True or false, Be containing alloys have proven to have devastating long term effects in dentists and patients, even at concentrations <3%
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False, no risk as long as proper ventilation is maintained in the operatory
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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 |
HVE
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What is the OSHA limit for Be? (concentration/time)
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2 micrograms/m^3 for an 8-hour exposure
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List the 3 alloys currently used at OUCOD... good luck...
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1. Argebond 80 (N alloy) for MCR
2. Argenco 58 (HN alloy) for all-metal restorations 3. Argenco 42 (N alloy) for cast dowels |
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List 5 alternative technologies to cast metal technology
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metal foil
CAD/CAM Copy milling electroforming new technologies |