Dental Materials Pt. 3 (27-35)

Question 1

polysiloxanes are hydrophoboic/philic

Answer 1

hydrophobic (consequences for taking impressions)

Question 2

polysiloxanes are cross linked by

Answer 2

hydrosilation reaction

Question 3

how can surfactants affect polysiloxanes?

Answer 3

can make them hydrophilic

Question 4

advantages of polysiloxanes

Answer 4

can repour!

dimensionally stable***

Question 5

disadvantages of polysiloxane

Answer 5

overcoming hydrophobic properties

Question 6

polyethers are hydrophilic/phobic

Answer 6

hydrophobic (but better surface characteristics

Question 7

polyethers can control viscosity to control

Answer 7

thickness of impression

Question 8

advantages of polyethers

Answer 8

good dimensional stability

Question 9

disadvantages of polyethers

Answer 9

stiff, bad taste, low tear strength

Question 10

unmixed ester can cause

Answer 10

contact dermatitis

Question 11

gypsum is hydrophilic/phobic

Answer 11

hydrphobic

Question 12

gypsum is cured how

Answer 12

water cured

Question 13

advantages of gypsum

Answer 13

dimensionally stable, doesn’t stain, no odor or taste

Question 14

disadvantages of gypsum

Answer 14

hard to vary set time, lots of bubbles, expensive

Question 15

if you add silicone to gypsum it releases

Answer 15

hydrogen gas

Question 16

calcination reaction

Answer 16

gypsum +water via heat= plaster

Question 17

reverse gypsum reaction

Answer 17

add water it releases heat and goes back to calcium sulfate

Question 18

properties of gypsum are dependent on

Answer 18

density and crystal structure

Question 19

is dental stone or plaster used for models?

Answer 19

dental stone

Question 20

denture base is normally

Answer 20

VLC

Question 21

provisionals are normally

Answer 21

chemically cured

Question 22

Mouthguards purpose

Answer 22

absorb impact

Question 23

mouthguards are thermoplastic or thermoset?

Answer 23

thermoplastic

Question 24

thermoplastic

Answer 24

can be melted and reformed

Question 25

thermoset

Answer 25

cant be melted and reformed

Question 26

function of cement

Answer 26

bind restorations to tooth

Question 27

requirements for cements

Answer 27

low viscosity
good mechanical properties
25 um thickness

Question 28

how are cement properties modified?

Answer 28

powder to liquid ratio

Question 29

More filler (powder) means more

Answer 29

viscosity

Question 30

restoration ratio of p/l

Answer 30

2.7:1

Question 31

low powder/liquid ratio increases

Answer 31

working and setting time

Question 32

resin cements are ____ based

Answer 32

water

Question 33

viscosity and strength of resin cements controlled by

Answer 33

powder to liquid ratio

Question 34

glass ionomers are ____ based

Answer 34

water

Question 35

glass ionomers adhere to

Answer 35

tooth structure

Question 36

glass ionomers release

Answer 36

fluoride

Question 37

disadvantages of glass ionomers

Answer 37

slow setting and looks bad

Question 38

purpose of bases and liners

Answer 38

protect pulp and minimize post op sensitivity

thermal/chemical barrier, controls inflammation, movement

Question 39

liners are a thin material used to protect

Answer 39

dentin from residual reactants

Question 40

liners have a ___ viscosity

Answer 40

low

Question 41

bases provide ____ for pulp

Answer 41

thermal protection

Question 42

bases provide mechanical support by distribution of

Answer 42

local stresses from restoration to underlying dentin

Question 43

calcium hydroxide is used for

Answer 43

pulp capping

Question 44

calcium hydroxide stimualates

Answer 44

odontoblast formation

Question 45

ZOE is used for

Answer 45

pain reduction

Question 46

ZOE can/cant be used with composite

Answer 46

cant, as it inhibits polymerization

Question 47

ZOE is a

Answer 47

sedative

Question 48

Wax requirements are

Answer 48

temporary, melt at low temps, carvable burn off, dimentionally stable

Question 49

lower molecular weight materials in between

Answer 49

polymers and organic liquids

Question 50

for mouthguards, copolymers control

Answer 50

properties