impression materials

Question 1

impression material classification via clinical classification (two types)

Answer 1

1. mucostatic = replica with soft tissues not compressed

2. mucocompressive = replica with soft tissues compressed

Question 2

impression material classification via its properties (two types)

Answer 2

elastic or non elastic
> viscoelastic = more strain needs applied to cause permanent deformation (but always some) = why remove from mouth in swift motion

Question 3

ideal properties of impression material clinically and for patient

Answer 3

clinically

• low viscosity for flow into tiny details
• no dimensional change in setting
• complete elastic recovery
• no dimensional change over time
• tear strength
• compatible with cast material

for patient

• taste
• non irritant/toxic
• no damage to oral tissues
• quick setting

Question 4

temp of water for alginate (impression material)

Answer 4

18-24 degrees celsius

Question 5

setting of alginate (impression material)

Answer 5

• long cross linked fibril entangling undissolved particles

Question 6

names for uptake and release of water from alginate impression material

Answer 6

uptake = imbibition 
release = syneresis

Question 7

alginate impression material negatives

Answer 7

• dimensional change in storage likely

- poor tear strength = avoid deep undercuts