Elastomeric Impression Materials Flashcards Preview

BDS2 Dental Material Science > Elastomeric Impression Materials > Flashcards

Flashcards in Elastomeric Impression Materials Deck (12)
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1
Q

what are examples of elastomer materials used in dentistry?

A
  • polyethers

- addition silicone

2
Q

what is an essential property of elastomeric materials required in dentistry?

A

must have elastic recovery as close to 100% as possible

3
Q

what are some essential properties an elastomer impression material must have in order to record accurate surface detail?

A
  • low viscosity (ability to flow over tooth surface)

- good wettability/contact angle between the tooth and material

4
Q

how might the stiffness of an elastomeric impression material affect its use in practise?

A

stiffness will determine how readily removed the material is from the mouth

5
Q

what is the ISO dental standard for impression materials?

A

grooves/indentations of either 20um or 50um (depending on material viscosity) are replicated

6
Q

what are the ideal properties of an elastomeric impression material when dealing with removal & undercuts within the mouth?

A
  • high tear/tensile strength

- low rigidity (flexible) so it is able to disengage easily & overcome bulbous part of tooth

7
Q

what is meant by viscosity? how does this property determine a materials use as an impression material?

A
  • a measure of a materials ability to flow

- determines a materials potential for making close contact with hard/soft tissue surfaces

8
Q

why is surface wetting important in an elastomeric impression material?

A

impression material must make intimate contact with teeth/mucosa surfaces (so all of surface is replicated)

9
Q

what would 100% elastic recovery in an impression material mean?

A

NO permanent strain on removal from mouth

10
Q

when removing an impression from the mouth, why is it done in a quick and hard manner?

A

if LOAD TIME is less, and impression is removed with a sharp pull, there is less overall permanent strain

11
Q

what is the tear strength of a material?

A

the stress a material will withstand before fracturing

12
Q

if a material is rigid, what is meant by this?

A

a large stress is needed to cause material to change shape