Gold Filling And Wrought Alloys

Question 0

Alloyed with calcium to increase strength. May also alloy with Pd, Pt, In, Ag

Answer 0

Alloyed electrolytic precipitate

Question 1

An electrolytic precipitate crystalline form sandwiched between sheets of gold foil and formed into strips which are then cut into desired size

Answer 1

Mat gold

Question 2

Process of joining metals together by pressure at room temperature rather than by heat

Answer 2

Cold welding

Question 3

Pressurized adaptation within the spaces between the tooth structure walls or corners

Answer 3

Wedging

Question 4

Step involving non cohesive DFG passing over a flame or placed on an annealing plate at 650-700C

Answer 4

Desorption, degassing, heat treatment

Question 5

What results when there is underheating?

Answer 5

Inadequate removal of surface impurities which can cause incomplete cohesion of DFG

Question 6

What results when there is overheating?

Answer 6

May lead to excessive sintering, contamination from the tray, instruments or flame and results in incomplete cohesion, embrittlement, poor compaction characteristics

Question 7

The process of controlled heating and cooling that is designed to produce desired properties in a metal

Answer 7

Annealing

Question 8

The increase in the mean crystal size of a polycrystalline metal produced by a heat treatment process

Answer 8

Grain growth

Question 9

The process of reducing the crystal size in a solid metal through the action of specific alloying elements or compounds. Make the material stronger

Answer 9

Grain refinement

Question 10

A stage in heat treatment that results in the partial restoration of properties of a work-hardened metal without a change in the grain structure

Answer 10

Recovery

Question 11

The process of forming new stress-free crystals in a work-hardened metal through a controlled heat treatment process

Answer 11

Recrystallization

Question 12

The amount of elastic strain that a metal can recover when loaded to and unloaded from its yield strength; an important property of orthodontic wires

Answer 12

Springback

Question 13

The reduction of residual stress by heat treatment

Answer 13

Stress relief

Question 14

The ability of certain nickel-titanium alloys to undergo extensive deformation resulting from a stress-assisted phase transformation, with the reverse transformation occurring on unloading

Answer 14

Superelasticity

Question 15

Sometimes called pseudoelasticity

Answer 15

Superelasticity

Question 16

SS used for surgical and cutting instruments because of its high strength and hardness; corrosion resistance is less than ferritic and austenitic SS

Answer 16

Martensitic

Question 17

Composition of austenitic SS

Answer 17

18% Cr- 8% Al- .2% Ca

Question 18

Strengthens and stabilizes the austenite phase by preventing conversion to martensite on cooling

Answer 18

Ni

Question 19

Formation of chromium carbide which is brittle and decreases corrosion resistance due to overheating

Answer 19

Weld decay

Question 20

Type of austenitic SS when niobium, tantalum or titanium is added

Answer 20

Stabilized austenitic SS

Question 21

Elgiloy; introduce in the 50s for orthodontic appliances; excellent tarnish and corrosion resistance

Answer 21

Co-Cr-Ni

Question 22

Introduced in the 70s; shape memory, spring back properties, super elasticity; used mostly in ortho and endo

Answer 22

Ni-Ti

Question 23

Composition of Ni-Ti

Answer 23

54Ni-44Ti-3Cr

Question 24

Major orthodontic wire that is nickel-free; popular in dental implants and cast restorations

Answer 24

Beta- titanium alloy

Question 25

Provides excellent corrosion resistance and environmental stability to beta-titanium alloy

Answer 25

Passive TiO2 surface film

Question 26

Composition of beta titanium alloy

Answer 26

Ti-6Al-4V (90%Ti-6%Al-4%V)

Question 27

Gives Ti-Mo alloy high formability thus can be bent into various configurations

Answer 27

Mo

Question 28

Occasionally used as RPD clasps, orthodontic appliances, endodontic posts, retention pins for restorations

Answer 28

Noble metals

Question 29

For RPD clasps; retention pins for large restorations

Answer 29

Co-Cr

Question 30

Process by which the surfaces of the metals being joined are mixed together to form union by applying heat, pressure or both, with or without a filler material

Answer 30

Welding

Question 31

Process of uniting metals by heating them and applying a filler metal

Answer 31

Soldering

Question 32

Similar to soldering but requires heating temp above 450C but below the solidus temperature of the substrate metal

Answer 32

Brazing

Question 33

Joining two components of a fixed partial denture by means of casting molten metal into an interlocking region between the invested components

Answer 33

Cast-joining

Question 34

Temperature at which the filler metal wets and flows on the substrate metal and produces a bond

Answer 34

Flow temperature

Question 35

The temperature at which metals of an alloy system begin to solidify on cooling or become totally liquid on heating

Answer 35

Liquid us temperature

Question 36

The temperature at which metals of an alloy system become completely solidified on cooling or start to melt on heating

Answer 36

Solidus temperature

Question 37

Technical term for joining metals before firing of the veneering ceramic layers

Answer 37

Presoldering

Question 38

Technical term for joining metals after firing of the veneering ceramic layers

Answer 38

Postsoldering/ postbrazing

Question 39

Metal that is prepared for joining to another substrate metal

Answer 39

Substrate

Question 40

Removes oxide coating from the substrate metal but use should be minimal as it may be entrapped in the filler causing weakened joint or discolor porcelain

Answer 40

Flux