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85 Cards in this Set
- Front
- Back
The lost wax technique uses ____ wax to produce crowns, inlays and veneers.
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Casting and inlay wax (1 &3)
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______ wax is used to produce patterns for metal castings through the lost wax technique. |
Inlay
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True Or false # 1 Range of temperatures at which each component of the wax will start to start to soften and then flow is referred to as melting point |
#1 false
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____ wax is used to adhere components of gypsum, metal, or resin together during fabrication and repair.
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Sticky wax
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True or false #2 Thermal expansion and contraction of waxes is greater than any other dental material |
#2 true
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The properties of waxes are ____________ |
Melting range, flow, dimensional change
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True or false #3 The wax is used to form a base into which to pour a gypsum model is boxing wax |
#3 true
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True or false #4 Temperature and time of storage for inlay pattern wax increases distortion |
#4 true
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Material that is suitable for forming a mold into which a metal or alloy is cast
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Investment
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What are the requirements for investment materials?
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A, B, C, D
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Gypsum bonded investment material is limited to ______ casting |
Gold casting
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Type of investment materials used or high fusing alloys used in metal ceramic restorations and pressable ceramics
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Phosphate bonded
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True or false #5
Spatulation of the investment materials increases the setting expansion |
#5 true
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True or false #6 Dental investments materials are classified depending on the binder material |
#6 true
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True or false #7 Increasing the water/powder ration, decreases the setting expansion time |
True #7 |
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For safety purposes always pour acid _________
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Into water
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In dental laboratories, Hydrochloric acid is primarily used for ________.
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Pickling
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Which component of Casting investments is associated with "reduction of oxidation"? |
Modifiers
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Most of gypsum investment expansion results from?
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Hygroscopic
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Muriatic acid is a trade name for ________
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Hydrochloric acid
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What is the importance of silica in dental investments
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It is a refractory skeleton
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Antiflux is used _________. |
To confine the molten solder to a definite area
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When considering "the rules for handling inlay wax", discussed in class a student will most likely have a better fitting casting if they ________ |
Always reseal the margins just before investing and invest immediately
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Contamination by copper in a pickling solution will impart a ________ color to the pickling solutions
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Blue-green
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Hydrofluoric acid is most often used __________. |
To strip porcelain
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True or false 8 Waxes have a coefficient of expansion and tend to warp and distort when allowed to stand unrestrained |
#8 true
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During soldering, fluxes act to __________. |
Prevent contact of atmospheric oxygen with the hot surfaces of the metal which would cause oxidation
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True or false #9 Fluoride is a type of flux mainly used for chrome cobalt, |
#9 true |
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Powder fluxes are used mainly for _________.
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Casting
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Fluxes containing H2O are used for __________.
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Electric soldering
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True or false #10 Type II inlay waxes have a lower flow in the mouth temperatures than type 1 inlay waxes |
#10 false
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The process of abrading a surface to eventually reduce the size of the scratches until the surface appears shiny
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Polishing
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The wearing away of a surface; irregular grooves or scratches are produces on a surface
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Abrasion
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abrasives in dentistry may be bound on the surface of:
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Burs, disks, wheels and stones
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Used to give metal a high luster
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Rouge
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In three grits; used to smooth metal or acrylic resin
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Pumice
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a powder is mixed with water to form paste |
Chalk
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Powder together with a binder. applied with a rag or brush wheel to smooth metal or acrylic resin
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Tripoly
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Used as an Arkansas stone
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Quartz
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arbor band mounted in a handpiece or lathe. Used to trim acrylic
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Emrery
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Used to finish gold; very fine |
Cuttlefish
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Highest MOH's Number |
Diamond
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True or false #11 Propane gas is cleaner and less hazardous than acetylene |
#11 true
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acetylene-compressed air may be used to melt a ceramic alloy |
#12 false |
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Colorless gas with a garlic-like odor
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Acetylene
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This type of gas is normally used in the warmer regions of the U.S. |
Butane
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True or false #13 When organic matter decomposes, it forms propane gas |
#13 false
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The temperature at which a substance changes from a liquid to a gas |
Boiling point
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gas with a triple bond
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Acetylene
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What is the smallest unit of matter that can exist as a stable independent entity?
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Atom
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Noble metals are defined by their: |
Resistance to corrosion
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When an 18Kt crown with BHN of 84 and a melting range of 1525°F1630°F is being soldered into a bridge, 650 fineness solder in the form of wire is going to be used. What percentage of this solder alloy in yellow gold?
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65%
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12 kt gold is the same as __________ fineness
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500 fineness
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Copper imparts a ______ color to gold alloys
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Red |
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pure metals are characterized by ________. |
Melting point |
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Heat hardening is accomplished by:
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Slow Cooling
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What alloy is more commonly used for partial denture frameworks? |
Type IV |
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In the grain structure lecture, the attraction of alloy component atoms or unit cells for one another are responsible for the "failure" of an alloy when:
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the load applied to the alloy was greater than the ultimate attractive force between atoms.
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How many grains are there per pennyweight?
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24 |
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When malleability increases in an alloy, what usually happens to ductility? |
It will also increase
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True or false #14 A unit cell is the smallest repeating unit of atoms fundamental to the properties of the alloy crystal. (simple bulling block) |
#14 True
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True or false #15 Grain structure is an orderly arrangement of an alloys component atoms or unit cells |
#15 true
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True or false # 16 Faced centered cubic unit cells represent the type of crystals formed by AU type alloys |
#16 True
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True or false #17 Predominant base alloys from body centered cubic cell crystals |
#17 True
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True or false #18 Imperfections in lattice structure are related to physical properties such as hardness, softness, resilience, etc. |
#18 True
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When alloy is made to be softer it also becomes ____ malleable.
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More
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Which of the following elements, when added to gold alloy, increases the hardness greatly?
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Copper |
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If a AU alloy becomes work hardened it may be returned to a soften state by:
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Controlled heating and quenching
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When an AU alloy becomes work hardened it may reveal the following characteristic:
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The metal becomes hardened and brittle
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The process of modifying gold alloy grains from granular to fiber like grain structure is called:
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Cold working.
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What other major metals are found in gold alloys for dental use? |
Platinum, Palladium, Copper. |
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_____ alloys are first cast but then shaped by mechanical forces into their final forms
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Wrought
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_______ bond, is responsible for many of the properties of metal's electrical and thermal conductivity, metallic luster and strength.
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Metallic
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What is ADA classification of a dental alloy containing 40% yellow gold, 12% platinum and 7% palladium.
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Noble
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What is ADA classification of a dental alloy with very hard characteristic.
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Type IV
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True or false #19 Porcelain metal alloy has a lower melting range than inlay gold metal |
#19 False
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True or false #20 It is a common practice to use the same crucible for both inlay gold alloy and porcelain gold alloy casting. |
False #20
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Identify causes of casting alloy porosity.
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Contamination of wax pattern, over heating of casing metal, gas trapped inside the mold, improper spruing
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Malleability is defined as:
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The ability to be mechanically formed |
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When a molten (liquid) alloy freezes, crystals______ and ______ as the material cools.
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Form;Grow
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Which of the following statements is(are) true of dental alloy crystal structure and grain?
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1, 2 and 3 are true statements.
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Which of the following statements is(are) true of the density of an alloy? |
1 and 3 are true statements
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According to the ADA classification for dental casting alloys, high noble alloys must have a noble metal content of at least ______% by weight
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60
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The___________attaches to the impression abutment and is used to replicate the implant fixture for the laboratory cast.
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Implant analog
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