Dental Materials Test #2

Front 1

What is a dental amalgam?

Back 1

Silver (65%) & Tin AND Mercury

Front 2

Name two kinds of amalgam alloy

Back 2

lathe cut (grind ingot)
spherical (spray molten metal into inert atmosphere)

Front 3

When was amalgam intitially developed?

Back 3

1800s in France

Front 4

What is the composition of Low copper amalgam?

Back 4

65% Silver,
25% Tin,
less than 6% copper,
sometimes 1% zinc

Front 5

What is the function of silver, tin, copper, and zinc in amalgam?

Back 5

Silver: setting expansion, increases strength and corrosion resistance.
Tin: Setting contraction, decrease strength.
Copper (like silver): setting expansion.
Zinc: reduce oxidation

Front 6

What is the weakest and most corrosion prone phase of copper?

Back 6

Sn-HG (tin-mercury) gamma 2 phase

Front 7

What % copper is in high copper amalgams?

Back 7

10-30%

Front 8

What two factors affect the handling and performance of amalgam?

Back 8

manufacturer and dentist

Front 9

Amalgam has high ____ strength

Back 9

compressive

Front 10

Amalgam has low _____ strength

Back 10

shear

Front 11

What is creep?

Back 11

slow change caused by compression

Front 12

Dental amalgam NOT recommended for what class of restoration?

Back 12

Class IV

Front 13

Why can zinc cause an amalgam to expand?

Back 13

reacts with water to produce hydrogen gas

Front 14

What percent of patients have mercury toxicity?

Back 14

<.1%

Front 15

Gold foil are limited to what class?

Back 15

Class V

Front 16

What are luting agents?

Back 16

cement (glue things together)

Front 17

Name two things that provide pulp protection

Back 17

liner (may stimulate dentin; calicum hydroxide)
base (thermal insulation; glass ionomer)

Front 18

What protects the pulpt from an irritating base or cement?

Back 18

varnish

Front 19

Name three liquids used in dental cements

Back 19

eugenol (oil of cloves)
phosphoric acid
polyacrylic acid

Front 20

Name five kinds of dental cements

Back 20

composite (or resin) for ceramic,
glass ionomer,
ZOE,
zinc phosphate,
glass ionomer (metal)

Front 21

Name two disadvantages of ZOE cement

Back 21

inadequate strength, high soluability

Front 22

Name a disadvantage of zinc phosphate cement

Back 22

irritates pulp (low pH)

Front 23

Why is a cooled glass slap used whem mixing zinc phosphate cement?

Back 23

releases heat (exothermic)

Front 24

What are two advantages of glass ionomer cements

Back 24

release fluoride, bond to tooth structure

Front 25

What is the cement of choice for luting metal or PFM crowns?

Back 25

resin modified glass ionomer

Front 26

Name a major disadvantage of polycarboxylate cement

Back 26

not strong

Front 27

Name three advantages of polycarboxylate cement

Back 27

kind to pulp (biocompatible),
releases fluoride,
bonds to tooth structure

Front 28

Name a liner that promotes the formation of secondary dentin

Back 28

Calicum Hydroxide (Dycal)

Front 29

What is the composition of Temp Bond, a temporary cement?

Back 29

ZOE + vegetable oil

Front 30

Name three types of impression trays

Back 30

stock, custom, triple

Front 31

Name three impression materials

Back 31

inelastic,
aqueous elastomeric,
non-aqueous elastomeric

Front 32

Name three types of inelastic impression materials

Back 32

wax, plaster, ZOE

Front 33

Name two types of aqueous elastomeric impression materials

Back 33

alginate, agar

Front 34

Name four types of non-aqueous elastomeric impression materials

Back 34

polysulfides,
condensation silicones,
polyethers,
addition silicones

Front 35

Which type of impression material returns to original form after deformation?

Back 35

elastomeric

Front 36

Will not reverse to a sol once set as a gel

Back 36

alginate (irreversible hydrocolloid)

Front 37

Warmer water (increases/decreases) the setting rate of alginate

Back 37

increases

Front 38

Used for study models and casts

Back 38

alginate

Front 39

Requires special impression trays that circulate cooling water

Back 39

agar

Front 40

What is a by product of condensation silicones?

Back 40

alcohol

Front 41

What are the most popular type of elastomeric impression material?

Back 41

addition silicone

Front 42

Name three disadvantages of polysulfides

Back 42

smell, staining, long working time

Front 43

Hydrocolloids will absorb water and distort, which is called____

Back 43

Imbibition

Front 44

What is the calcination process?

Back 44

heating process of gypsum to drive off water

Front 45

Name three types of gypsum products

Back 45

plaster, stone, improved stone

Front 46

Which gypsum is weakest and least expensive?

Back 46

plaster (white)

Front 47

Which is used by ortho to make study models?

Back 47

plaster (white)

Front 48

Which type of gypsum is yellow and referred to as alpha-hemihydrate?

Back 48

stone

Front 49

Which type of gypsum is used to make dies?

Back 49

improved stone (pink)

Front 50

What is the setting reaction when hemihydrate is mixed with water?

Back 50

hydration, back to dihydrate (exothermic).
Opposite of calcination

Front 51

Why does plaster require more water to wet powder surfaces than stone?

Back 51

surfaces are irregular on particles

Front 52

What is the water/powder ratio for plaster and stone?

Back 52

plaster: 45-59 mL/100g
stone: 28-30 mL/100g

Front 53

The final setting time for gypsum products is:

Back 53

30-45 min

Front 54

A retarder used to increase setting time (sets slower) is?

Back 54

borax (or water)

Front 55

A (higher/lower) water powder ratio decreases setting time (sets faster).

Back 55

lower water (thicker mix)

Front 56

Which has the most expansion: plaster or stone?

Back 56

plaster

Front 57

Dry strength is measured when?

Back 57

excess water is gone

Front 58

Dry strenght may be ___ times stronger than wet

Back 58

2-3 times stronger

Front 59

Which is placed in the mixing bowl first: water or powder?

Back 59

water

Front 60

Indirect restorations are constructed where?

Back 60

lab (outside the mouth)

Front 61

Onlays restore what?

Back 61

cusp

Front 62

Crowns restore what?

Back 62

teeth that have lost significant tooth structure

Front 63

Bridges replace what?

Back 63

missing teeth

Front 64

Veneers are placed where?

Back 64

facial of anterior teeth

Front 65

Ceramic metals lack what?

Back 65

toughness and fracture resistance

Front 66

Another name for temporary restoration

Back 66

provisional

Front 67

Name of the wax used for crowns

Back 67

inlay casting wax (dark blue)

Front 68

Name of wax used in fabricating dentures

Back 68

baseplate wax (pink)

Front 69

Attach wax pattern to creat opening for the mold

Back 69

sprue

Front 70

Mold must expand to compensate for what?

Back 70

shrinkage of the material

Front 71

What is refractory?

Back 71

improves investment's resistance to heat (usually silica)

Front 72

What is burnishing?

Back 72

pushing metal against tooth to close a gap

Front 73

What are the noble metals?

Back 73

gold, platinum, palladium

Front 74

What are the precious metals?

Back 74

noble metals (gold, platinum, palladium) and silver

Front 75

carat is parts per ____

Back 75

24

Front 76

Fineness is parts per ____

Back 76

1000

Front 77

Twelve carats is ___ fineness?

Back 77

500

Front 78

High noble is ____% gold or noble elements?

Back 78

68%

Front 79

Base metals are less than ____% noble elements

Back 79

25%

Front 80

What is "sintering porcelain"?

Back 80

heating to change powder to solid

Front 81

What is the material of choice for implants?

Back 81

titanium

Front 82

What metal is commonly used in partial dentures?

Back 82

nickel chromium/cobalt chromium

Front 83

What is a PFM crown?

Back 83

porcelain fused to metal

Front 84

What does CAD/CAM mean?

Back 84

computer aided drafting and manufacturing