fixed

Question 1

Does impression material get larger or shrink upon setting

Answer 1

shrink

Question 2

Rigid impression materials:

Answer 2

zinc oxide and eugenol impression paste

impression plaster

Question 3

For synthetic elastomers, ____ polymerize into elastomers?

Answer 3

oligomers

Question 4

LIGHT body has ___ viscosity and ____ setting contraction

Answer 4

low viscosity

high setting contraction

Question 5

Thermoplastic polymer:

Thermoset:

Answer 5

thermoplastic: no-cross linking. physical state reversible by temp (wax)
thermoset: has cross-linking

Question 6

Condensation polymerization results in a:

Answer 6

by-product

Question 7

POLYSULFIDE needs a _____ of impression material to stay accurate

Answer 7

minimum amount

Question 8

Silicones (Polysiloxanes) are inherently ____ but the addition type can be made more ______

Answer 8

hydrophobic

hydrophilic

Question 9

Addition silicone (polyvinylsiloxane) you should wait to pour model until:

Answer 9

hydrogen liberated

Question 10

Most hydrophilic impression material?

Answer 10

polyether

Question 11

Good wetting = ____ contact angle

Answer 11

low

Question 12

Die stone has __% expansion.

Gold alloy can shrink up to __%

Answer 12

0.1%

Gold=2%

Question 13

Starting material for gypsum is calcium sulfate __hydrate

Answer 13

di-hydrate

Question 14

Typical water-to-powder ratio of high-strength die stone:

Answer 14

0.2-0.3

Question 15

Common accelerator:
Common retarder:
What can be used for both:

Answer 15

accelerator: potassium sulfate
retarder: borax
both: NaCl

Question 16

Which die stone type has lowest setting expansion and contain larger amounts of modifiers?

Which die stone is high strength AND high expansion (for “modern” use)?

Answer 16

Type IV

Type V

Question 17

Gypsum has very _____ compressive strength, but very ___tensile strength

Answer 17

high compressive

low tensile

Question 18

Composition of gypsum-bonded casting investment powder:

Answer 18

refractory (quartz): 1/2 - 2/3
binder (stone): 30-45%
chemical modifiers: 3% or less

Question 19

Gypsum is _____ form in set material

Answer 19

dihydrate

Question 20

Cristobalite, quartz, and tridymite are versions of ____.

Which has highest thermal expansion?

Answer 20

SiO2

Critobalite

Question 21

Normal thermal expansion with temp increase..
Cristobalite:
Quartz:

Answer 21

Cristobalite: 200-270C
Quartz: 575C

Question 22

What is special solution?

Answer 22

Silica sol in water

Question 23

Advantage of phosphate-bonded investment:

Answer 23

withstand burnout temp of 900*C

Question 24

Effect of length of deflection:

Effect of connector height on deflection:

Answer 24

D=L^3

D=1/(H^2)

Question 25

Crown/root ratio

Answer 25

2:3

Question 26

Modified hygienic pontic just has ____ connectors than normal

Answer 26

wider

Question 27

What is an ovale pontic

Answer 27

goes into gum space

Question 28

Retention form: | Resistance form:

Answer 28

retention: POW resist: lateral

Question 29

#1 cause of FPD failure:

Answer 29

caries (23%)

Question 30

Glass will adhere to _______ metal if covered with _____ and temp raised where _____ is partially dissolved into the metal

Answer 30

clean, gas free | adherent oxide

Question 31

You want 90* metal/porcelain junction (T/F)

Answer 31

True

Question 32

Zinc _____ cement has moderate pulp irritation. Adequate strength. Use cool glass slab. Zinc _____ is only used for single metal units with less stress.

Answer 32

phosphate polycarboxylate

Question 33

Why is glass ionomer cement hard to use?

Answer 33

any moisture ruins it.

Question 34

Which cement has highest compressive strength? Which cements release flouride

Answer 34

glass ionomer glass ionomers

Question 35

which cement is highest strength?

Answer 35

composite resin

Question 36

Pretzel has high ___ and low ___. Twizzler has high ____ ability

Answer 36

high strength, low strain strain

Question 37

What has higher tensile strength (dentin or enamel)

Answer 37

dentin

Question 38

Mechanisms to improve alloy mechanical properties:

Answer 38

solid solution hardening + grain refining

Question 39

Small amounts of _____ produce metals with very fine grains

Answer 39

Ir + Ru

Question 40

Casting alloy hardness classification.. | Type I is ____ while Type IV is _____

Answer 40

``` I = softest IV= hardest ```

Question 41

3 components of dental porcelain

Answer 41

potash feldspar quartz kaolin (clay)

Question 42

what kinds of bonds does ceramic have?

Answer 42

ionic and covalent

Question 43

Building block of dental porcelain:

Answer 43

SiO4

Question 44

Melting point of porcelain must be ____ than metal

Answer 44

LOWER

Question 45

Porcelain must ____ the surface of metal

Answer 45

wet