Test #2-3

Question 1

What are the requirements of impression material

Answer 1

ease of manipulation
resonable cost
adequate viscosity properites
safety
pt acceptance
compatability with die
adequate shelf life
appropriate setting time

Question 2

what should be the mechanical strength of impression materials

Answer 2

should resist tearing and permanent deformation during removal

Question 3

what is an important requirement of imp material

Answer 3

dimensionally accurate

Question 4

when are impressions used during fixed restorations

Answer 4

crowns, bridges, inlays, onlays, study models

Question 5

what are impressions used for in removable appliances

Answer 5

pediatric, ortho appliances, dentures, partials, study models

Question 6

what are impressions used for in esthetic appliances

Answer 6

bleaching trays, temporary partials

Question 7

what is rigid

Answer 7

unable to remove from undercuts

Question 8

what is flexible

Answer 8

capable of removal from undercuts

Question 9

what is a hydrocolloid

Answer 9

a colloidal suspension in which water is the liquid*

Question 10

what is a colloid

Answer 10

substance dispersed evenly throughout another substance * liquid/solid/gas

Question 11

agar

Answer 11

organic hydrophilic colloid extracted from seaweed

Question 12

what are reversible hydrocolloid steps

Answer 12

• advanced prep of material
• prep immediately before impression
• impression

Question 13

what are the components of a reversible hydrocolloid

Answer 13

agar, thixotropic materials, structure, thickness

Question 14

What is an example of a irreversible hydrocolloid*

Answer 14

alginate

Question 15

what are alginate impressions accurate enough for

Answer 15

study models, working casts, pt education , bleach trays, essex trays, temps

Question 16

• what can alginate not be used for

Answer 16

-to fabricate indirect restorations

Question 17

can alginate be softened after setting

Answer 17

no

Question 18

what is imbibition*

Answer 18

taking on water

Question 19

what is syneresis*

Answer 19

shrinkage

Question 20

what does warm water do to alginate*

Answer 20

accelerates reaction

Question 21

what does cold water do to alginate*

Answer 21

slows reaction

Question 22

how does alginate set

Answer 22

by chemical reaction

Question 23

what are inelastic/rigid impression materail

Answer 23

plaster, compound, ZOE

Question 24

What is ZOE used for*

Answer 24

impressions, bite registration, perio dressings, temp cements, temp restorative materials

Question 25

When can you use a rigid/inelastic impression compound

Answer 25

for single tooth impressions

Question 26

What is the viscosity of a flexible elastomeric-rubber base impression material

Answer 26

light body (low viscosity, better flow/detail)

Question 27

When is regular body elastomeric used

Answer 27

when detail is not critical

Question 28

when is heavy body elastomeric used

Answer 28

for the bulk of the tray-stability

Question 29

how is the elastomeric impression material packaged

Answer 29

- 2 tubes: light, medium, heavy body - cartridge - disposable pouches - putty

Question 30

how many types of rubber bases are there

Answer 30

4

Question 31

what is a polysulfide rubber base*

Answer 31

catalyst is lead-hazardous oldest rubber base sulfur- bad odor

Question 32

what is a polyether rubber base

Answer 32

shortest working time can pour repeatedly in 24 hrs irritates skin poor tear strength

Question 33

what are condensation silicone rubber bases

Answer 33

- base dimethyl siloxane - catalyst- tin octoate - gives off water/shrinks - less flexible than addition silicones

Question 34

what are addition silicone rubber bases

Answer 34

polyvinylsiloxane most popular and most costly no shrinkage as it sets

Question 35

what are some qualities about addition silicones

Answer 35

more accurate and stable tasteless odorless colorless doesnt stain clothes quick and easy to mix

Question 36

gypsum

Answer 36

calcium sulfate, mined from the earth and processed

Question 37

what is gypsum used for

Answer 37

models, indirect and direct restorations, mouth guards, bleach trays

Question 38

what are models

Answer 38

replicas of hard and soft tissue for study

Question 39

what are casts

Answer 39

working replicas of hard and soft tissues for use in the fabrication of appliances or restorations

Question 40

what is a die

Answer 40

working replicas of one or more teeth used for fabrication of a restoration

Question 41

what is an expoly die*

Answer 41

- resin molecule | - made by mixing epoxy material and forcing into the impression

Question 42

what is electroplating*

Answer 42

metal plating by electrolysis, plated to form metalized working dies

Question 43

what is electrolysis*

Answer 43

the decomposition of a substance by passage of an electric current through it

Question 44

What is made from calcium dyhydrate*

Answer 44

all gypsum products, plaster and stone

Question 45

when calcium hemihydrate powder is mixed with water for impression it reacts with the hemihydrate it then ________________*

Answer 45

reverts back to a dihydrate

Question 46

What color is plaster

Answer 46

white

Question 47

What kind of particles does platster have

Answer 47

porous irregularly shaped particles

Question 48

what color is dental stone

Answer 48

buff or yellow color

Question 49

what are the particles like in stone

Answer 49

denser more regular shaped particles

Question 50

What color is die stone

Answer 50

pink, green , blue or yellow

Question 51

What are factors that determine properties of gypsum products

Answer 51

size, shape, and porosity of the particles

Question 52

what are the desireable qualities of gypsum products

Answer 52

accuracy, dimensional stability, fine detail, strength and resistance to abraision, ease of adaption

Question 53

waht kind of reactions do gypsum products have

Answer 53

*exothermic

Question 54

** what is the written mixing reaction

Answer 54

calcium sulfate hemihydrate (plaster/stone)-calcium sulfate dihydrate (gypsum)+ heat

Question 55

what does extra water do to the setting time of model and die materials

Answer 55

increases the setting time

Question 56

**When you increase the temp of the water for model and die materials what happens? decrease the temp?

Answer 56

- faster setting | - slower setting

Question 57

*what can decrease the setting time of model and die material

Answer 57

potassium sulfate

Question 58

*what can increase the setting time of model and die material

Answer 58

borax

Question 59

What is type 1 plaster and stone*

Answer 59

impression plaster

Question 60

What is type 2 plaster and stone*

Answer 60

model plaster

Question 61

What is type 3 plaster and stone*

Answer 61

laberatory stone

Question 62

What is type 4 plaster and stone*

Answer 62

die stone