Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Dental Materials LEC > Elastomers > Flashcards

Elastomers Flashcards

1
Q

The process of changing the rubber
base product or liquid polymer to a rubber-like material.

A

Vulcanization/Curing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Classification of Elastomers based on chemical composition

A
  1. Polyether
  2. Polysulfides
  3. Silicones
    a. Addition
    b. Condensation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Types of consistency/viscosity for rubber impressions

A
  1. Light bodied impression
  2. Regular/medium bodied
  3. Heavy bodied
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

A group of flexible chemical polymers that are either chemically
or physically cross-linked.

A

Elastomeric Impression Materials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

T or F

Elastomeric impression materials can be easily stretched and rapidly recover their original dimensions when applied stresses are released

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Introduced in Germany in late 1960’s and first elastomer to be developed as impression material.

A

Polyether

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Polyether Base and Catalyst

A

Base
- polyether polymer
- colloidal silica (filler)
- glycol ether or phthalate

Catalyst
- alkyl aromatic sulfonate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Advantages of polyether

A
  • Fast working and setting time
  • Less hydrophobic (better wetting)
  • Long shelf life
  • Proven accuracy
  • Adequate tear strength
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Disadvantages of polyether

A
  • Clean but tastes bad
  • Slightly more expensive
  • Stiffness requires blocking undercuts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

First non-aqueous elastomeric impression material often called “rubber” or “rubber base”

A

Polysulfide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Polysulfide Base and Catalyst

A

Base
- Lithopone and titanium
dioxide (filler)
- Dibutyl phthalate (plasticizer)
- Sulfur (0.5%)

Catalyst
- Lead dioxide (dark
brown color)
- Oleic and stearic acid
(retarders)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Polysulfide disadvantages

A
  • Requires a custom tray
  • Odor (unpleasant)
  • Messy and stains
    clothes
  • Second pour is less
    accurate
  • Potential for significant
    distortion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

It was the first type of silicone impression material, and also known as conventional silicones.

A

Condensation silicone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

supplied as a base paste and a low-viscosity liquid catalyst, a two-paste system, or a two-putty system

A

Condensation silicone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Condensation silicones advantages

A
  • Adequate working and
    setting time
  • Pleasant odor and no
    staining
  • Adequate tear strength
  • Better elastic properties
    on removal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Condensation silicone base and catalyst

A

Base
- Colloidal silica
- Metal oxide (filler)
- Colorants (homogenous
mix)

Catalyst
- Alkyl silicate and organo-tin compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Condensation silicones disadvantages

A
  • Poor dimensional
    stability
  • Slightly more expensive
  • Putty wash method is
    technique sensitive.
  • Potential for significant
    distortion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Frequently called as polyvinyl siloxane, and introduced after condensation silicones.

A

Addition silicone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Commonly used in complete denture.

A

Addition silicone

16
Q

Advantages of Addition silicones

A
  • Shorter setting time.
  • Easy to mix (automatic mixing devices)
17
Q

Addition silicones disadvantages

A
  • More expensive (automatic mixing
    device)
  • Hydrogen gas evolution
    in some materials
18
Q

Suspension of fine particles within a liquid.

A

Colloids

19
Q

Colloids in water

A

hydrocolloid

20
Q

Types of Colloids (2)

A

Lyophilic - liquid loving sols
Lyophobic - liquid hating

21
Q

Any solution in which the unit of the
solute are sufficiently large so that it will not dialyze through a suitable
membrane.

A

Colloids

22
Q

A substance that forms a gel with water.

A

Hydrocolloid

23
Q

Tis is made up of submicroscopic fibrils, with spaces in between called _____

A

Micelles

24
Q

Particles in a solution.

A

Dispersed particles

25
Q

solution containing a suspension of
particles.

A

Dispersed Medium

25
Q

Suspension

A

The dispersed phase and the dispersion medium are not of like phase.

25
Q

Tendency to demonstrate a strong
aversion to water.

A

Hydrophilic

26
Q

The dispersed phase is of the same
phase as of the dispersion medium.

A

Emulsion

26
Q

Tendency to demonstrate a strong
affinity for water.

A

Hydrophilic

27
Q

(agar) a colloid that contains water as the dispersion phase.

A

Hydrocolloid

28
Q

Agar impression material.

A

Reversible Hydrocolloid

29
Q

Alginate impression material.

A

Irreversible Hydrocolloid

30
Q

The transformation from a hydrocolloidnsol to gel.

A

Gelation

31
Q

The time needed to transform sol to gel.

A

Gelation time

32
Q

the temperature in which the sol is
transformed into gel.

A

Gelation temperature

33
Q

The transformation from gel to sol.

A

Liquefaction

34
Q

Time needed to transform gel to sol

A

Liquefaction time

35
Q

the temperature at which the gel is
transformed to sol at a higher
temperature. (60-70C)

A

Liquefaction temperature

36
Q

the difference between gelation
and liquefaction temperature.

A

Hysteresis

37
Q

Process of water sorption

A

Imbibition

38
Q

expression of fluid onto the surface of gel structures.

A

Syneresis

39
Q

expression of fluid onto the surface of gel structures.

A

Setting time

40
Q

The total time from the start of mixing to the final time at which an impression tray can be fully seated without distortion.

A

Working time

Dental Materials LEC (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions