Impression Materials (basics) Quiz 2

Question 1

What is the objective of impression material?

Answer 1

to obtain an accurate negative copy of an intra-oral structure: single tooth, quadrant, arch, soft tissue

Question 2

general concept of impression material?

Answer 2

A material that is initially viscous but flowable liquid that can transform into a rigid brittle inelastic solid OR an elastomeric solid (allows the to make molds/impressions)

Question 3

What is desired elastic strain and modulus for elastomeric material?

Answer 3

a material with low elastic modulus, high elastic strain limit. Desire a snap set after the try is seated

Question 4

clinical classifications?

Answer 4

1) inelastic

2) elastomeric

Question 5

setting mechanism classification

Answer 5

1) chemical reaction

2) change of state (cooling)

Question 6

Inelastic used for?

Answer 6

soft tissue, edentulous

Question 7

elastomeric used for?

Answer 7

Dentulous mouth, can be withdrawn from around undercuts without permanent distortion; general purpose

Question 8

Explain setting mechanism chemical reaction

Answer 8

2 or more ingredients mixed, primary bonds formed, irreversible

Question 9

setting mechanism: examples of change of state

Answer 9

cooling. secondary bonds, reversible, thermoplastic

Question 10

Requirments of impression material

8

Answer 10

1) minimum dimensional change during polymerization
2) no dimensional change during storage
3) suitable working, setting times
4) good tear strength
5) requires minimum equipment
6) compatible with gypsum
7) non-toxic, non-irritating
8) acceptable odor and taste