Impression composition materials

Question 1

2 types of impression composition materials?

Answer 1

green (greenstick)
red

Question 2

greenstick rigid or flimsy?

Answer 2

rigid (non-elastic) impression material

Question 3

What is greenstick used for?

Answer 3

used for border moulding of impression trays especially the post dam region

Question 4

is greenstick mucocompressive or mucostatic?

Answer 4

mucocompressive

Question 5

Why should greenstick be mucocompressive?

Answer 5

to get an accurate impression - usually on special tray

ensure adequate peripheral seal

also good at control and retaining amount of impression material in impression tray - allows it to not flow everywhere

Question 6

chemical constituents to control consistency of greenstick?

Answer 6

reisns (shellac)

waxes (colophony, beeswax etc)

Question 7

what might pt be allergic to in greenstick?

Answer 7

the colophony wax

Question 8

fillers used in greenstick?

Answer 8

calcium carbonate

Question 9

what is used to control consistency an rigidity of greenstick>

Answer 9

limestone

Question 10

what is used as a colouring agent in greenstick?

Answer 10

talc

Question 11

How would you describe greenstcok in relation t heating?

Answer 11

termoplastc material

Question 12

thermoplastic material meaning?

Answer 12

when heated it softens an dcolled down it hardens again

Question 13

transition temo f greenstick?

Answer 13

55-60 dc

Question 14

How to heat greenstick?

Answer 14

water or flame

Question 15

Market name for red compo?

Answer 15

Kerr hawe

Question 16

Indication for red compo?

Answer 16

first impressions in the edentulous arch

Question 17

Describe reed compo in relation to heating?

Answer 17

thermoplastic

Question 18

Chemical constituents of red compo to control consistency?

Answer 18

resins (e.g. shellac)

waxes (e.g. bees wax or colophony)

Question 19

constituents in red compo:

fillers
control consistency an rigidity
colouring agent?

Answer 19

calcium carbonate

limestone

talc

Question 20

trasnsition temp of red compo?

Answer 20

55-60

softens above this temp and hardens belwo

Question 21

What occurs if you overheat the impression compounds?

Answer 21

excessive heating causes some volatile components to be lost from the material

or leach out into hot water

Question 22

What happens if the material isnt completely softenened>

Answer 22

internal strains occur

Question 23

wet kneaded?

Answer 23

material is manipulated by hand when wet - improves flow

Question 24

viscosity of red compo?

Answer 24

highly viscous

Question 25

red compo mucocompressive or mucostatic?

Answer 25

mucocompressive as it is highly viscous

Question 26

Flaws of red compo?

Answer 26

poor reprocdction of fine detail - ok for primary imp

dimenstional stability poor - 1.5% shrinkage

Question 27

How quickly do you need to cast the primary impression using red compo?

Answer 27

within the hour

Question 28

Chairside hanfling of red compo?

Answer 28

very hot water required

water cooled quickly so may need to reheat to soften adequately

line dish with guaze

leave for a minute to soften

manipulate material to ensure the bulk is fully softened

place into the impression tray

replace back into the bath to resoften the material

check it is not too hot for intra-oral use

impression taken

cool impression under cold running water and removal

can replace cold impression back in mouth to check retention of impression

Question 29

impression decontamination steps for red compo?

Answer 29