IMPRESSION MATERIALS Flashcards

1
Q

Negative reproduction

A

Impression

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2
Q

Positive reproduction

A

Model or cast

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3
Q

Compression of tissues during impression to stimulate amount of pressure during function

A

Pressure (functional)

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4
Q

Oversize tray,no border molding,Zoe impression paste

A

Non selective (mucostatic)

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5
Q

Uses custom trays,best suited for withstanding forces of mastication

A

Selective

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6
Q

Most common,used to any patient

A

Perforated stock trays

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7
Q

Any individual jaw
Advantage: stability,lack of displacement

A

Custom trays

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8
Q

Most important factor in takin accurate impression

A

Size of impression tray

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9
Q

Hydrocolloid

A

Alginate
Agar hyrdrocolloid

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10
Q

Elastomeric

A

Addition silicones
Polyether
Condensation silicone
Polysulfide

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11
Q

Bite registration

A

Addition silicones
Polyether

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12
Q

Rigid

A

Impression compond
Zinc oxide eugenol

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13
Q

Types of impression materials in dentistry

A

Hydrocolloid
Elastomeric
Bite registration
Digital
Rigid

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14
Q

-Flexible cross linked polymers when set

-dominate the market mainly as a result of their greater accuracy, dimensional stability with time, and
ability to record detail as compared with the hydrocolloid materials.
-The first elastomeric impression mate

A

Elastomeric impression Materials

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15
Q

-AKA: polysiloxanes (VPS)
-Two paste or a two putty system
-no volatile by-product (such as water or ethanol) is formed in this reaction, minimal dimensional change occurs during polymerization.

A

Addition silicone

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16
Q

It is poorly wetted by water with a contact angle of 90°

A

hydrophobic surface

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17
Q

is readily wetted by water with a low contact angle.

A

hydrophilic surface

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18
Q

-have properties similar to the addition silicones.
-is hydrophilic and exhibits good wetting properties, even in a moist field.
-have the disadvantage of limited dimensional stability over time and older materials had poor taste.
-supplied as a base and catalyst system.

A

Polyether

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19
Q

Notes as short working times 1.5 to 3 minutes

A

Addition silicones

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20
Q
  • This impression material is supplied as a base and an accelerator
    -The multifunctional ethyl silicate produces a network or cross-linked structure that partly accounts for the low values of permanent deformation and flow
    -are not used commonly in the dental office but rather are used as an accurate duplicating material in the dental laboratory.
    -The setting reaction is sensitive to moisture and heat, with increases in either resulting in shorter setting and
    working times
A

Condensation silicone

21
Q

-Also called rubber base or mercaptan
-supplies as two paste
-The permanent deformation values of 2% to 3% (elastic recovery of 97% to 98%)
-shrink 0.3% to 0.4% dur- ing the first 24 hours

A

Polysulfide

22
Q

Impression compound
ZOE

A

Rigid impression material

23
Q

Impression compound is composed of?

A

-resins
-waxes
-organic acids
-fillers
-coloring agents
-sticks or cones

24
Q

Low fusing material 45c

A

Type 1

25
Q

High fusing material 70c

A

Type 2

26
Q

High fusing material 70c

A

Type 2

27
Q

Hard set of ZOE?
TYPE 1 OR 2?

A

TYPE 1

28
Q

Soft set of ZOE?
Type 1or 2?

A

Type 2

29
Q

-material consists of a matrix of amorphous zinc eugenolate that holds the unreacted zinc oxide particles together.
-Elastomeric impression materials almost have eliminated the use of zinc oxide–eugenol impression pastes for
edentulous impressions.

A

Zinc oxide eugenol

30
Q

Tube 1 base?

A

Zink oxyde 87%

31
Q

Tube 2 reactor?

A

Eugenol 12-15%

32
Q

1st impression material, least dimentionally stable

A

Hydrocolloid

33
Q

Process of absorbing water

A

Imbibition

34
Q

Process of releasing water= shrinkage

A

Syneresis

35
Q

Mixture of 2 phases

A

Colloid

36
Q

Colloid that contains water

A

Hydrocolloid

37
Q

-First successful flexible aqueous impression material use in dentistry
-longest shelf life

A

Agar “irreversible hydrocolloid”

38
Q

The agar gel is converted to a sol by heating in water, usually boiling, 100° C, and becomes a gel again by cooling to 43.3° C

A

Hysterisis

39
Q

Agar hydrocolloid impression material is called a

A

reversible hydrocolloid

40
Q

Agar Component:
Main component

A

Agar

41
Q

Agar Component:
Strengthen the gel

A

Borax

42
Q

Agar Component:
Plaster hardner

A

Sulfates

43
Q

Agar Component:
Most abundant

A

Water

44
Q

Components:
Fillers

A

Wax

45
Q

Agar Component:
Plasticizer

A

Glycerine

46
Q

Agar Component:
Bactericidal

A

Thymol

47
Q

-is one of the most widely used aqueous dental impression materials
-used extensively to prepare study models of either the entire dental arch or a segment of it.
-They also are used to prepare gypsum models for the preparation of athletic mouth protectors.

A

Alginate

48
Q

Function:
To dissolve in water

A

Sodium or potassium alginate salt

49
Q

Function:
to react with dissolve alginate to form insoluble calcium alginate

A

Calcium sulfate