Brainscape's Knowledge GenomeTM

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


See full index

Dm > Elastic Impression > Flashcards

Elastic Impression Flashcards

1
Q

non aquas Elastomeric

A

Groub of synthtic polymer that atr vhemicaliy cross linked and can be streched and returns to its original shape

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

Non-aqueous Hydrocolloids

A

Dif in the setting meachnism and physical and chemical properties

Base paste + base catalist = either by product or not

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

Polysulfides

A

Has a base filler and
Catalist or reacter filler - lead dioxide - gives strenght and brown stain

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

Polysulfides raction

A

It has a water by product

Lossing of the material can affect the dimintional stability of the impression

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

Polysulfides
Proprties

A

Working time/ 5-7 which is the longest amoung the elastomers
Setting time /8-12 long
High tear strenth and elastic proprties

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

Why the Polysulfides not liked by the paitents

A

Odor taste
Long setting time
Premanent stain on the clothes -Lead peroxides-

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

Polysulfides
Clinical Tips During Manipulation

A

Humdifiy and tm decrease the working time
Hydrophobic - nomouiseter during preparation
Slight contraction during polymrizition - costum impression tray-

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

Polysuflied For maximum accuracy,

A

Pouring the cast: impression must be poured within 30 min. to 1 hr.

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

Condensation Silicone material

A

2 paste system
2 putty system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Two putty system

A

Putty used as a tray in conjction with the lo viscosty silicon
Putty wash technique

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Condensation Silicone by product

A

Eythel-alchol and wen its evaporate it will cause contraction of the impression

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

Condensation Silicone
Properties:
• OVERCOME some of polysulfide’s disadvantages

A

Odorless and pigmented
Less setting time / 6-8 min
Less afected by the heat and tm / humidity

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

Who’s more stable

A

The polysufied more stable than the condensition silicon but the silicon moe stable than the reversible hydrocolloid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Condensation Silicone
Clinical Tips During Manipulation

A

Its hydrophobic in nature during the pouring its harder to avoid air bubbles in con silicon than any other elastomric material

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

Addition Silicone

A

Polyvinyl Siloxane (PVS)——-Vinyl Polysiloxane (VPS)
§ The base paste contains:
- Polymethylhydrosiloxane
- Divinylpolysiloxane.
§ The catalyst (or accelerator) paste contains:
- Divinylpolysiloxane
- Platinum salt.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Addition silicon by product

A

It has no byproduct so its dimintionally stable

But if there is any reminings from the polyether then a 2nd reaction will happen which will produce hydrogen gas and still wont affect the stability

17
Q

Addition Silicone
Properties:
Similar to condensation silicone in may aspects, EXCEPT

A

Affected by the tm
More dimintionly stable

18
Q

Addition Silicone
Properties: abt the hydrophobic

A

Some formulition has a hydrophilic proprties Surfactant/ Surfactant migrates toward the surface of the impression material and makes the surface more wettable by water.

19
Q

Addition Silicone
Clinical Tips During Manipulation

A
  • Delayed Pouring (Earlier product)
    Hydrogen gas evolved result in > pinpoint voids in the gypsum casts poured soon after removal of the impression from the mouth.

-Immediate Pouring (Newer product)
Manufacturers may add a noble metal, such as palladium, as a scavenger for the released hydrogen gas

-No latex gloves during mixing
§ Setting inhibition caused by some brands of latex gloves

20
Q

Polyether

A

§ The material is supplied as two pastes

The base paste contains:
- the polyether polymer,
- Filler: colloidal silica
- Plasticizer : glycol ether or phthalate.

The accelerator paste contains: - an alkyl-aromatic sulfonate
- in addition to Filler &Plasticizer

21
Q

Polyether byproducts

A

None

22
Q

Polyethyer Properties:

A

Short working time / decreased the number of teeth that will be captured during one impr
Short setting time
Stefness of the matirial
Alrergic reaction

23
Q

Properties of the polyether

A

Hydrophilic in natrure
Stable only if stored dry

24
Q

VPES

A

New impresion
Polyeteh+vps

Excelent flow
High tear strenght
Hydrophilicty
Elastisty

25
Q

Making impressions with elastomeric materials
Fabrication of gypsum models ,casts and dies involves 6 major steps:

A

1- prepare the try
2-prepare the tissue
3-prepare the matirial
4-taking the impression
5-remove the impression
6-prepare the stone cast

26
Q

Prepare the tray

A

To use less impression matirial as possible
Equal distribution of the impresion between the object and the tray -Especially for polysulfide impression material-

In case of severe undercuts the tray is avoided

Adhesive application
Prior to impression making, uniform thickness of adhesive should be applied to the tray

27
Q

Prepare the tissue

A

Gingival retraction cord to displace
the gingival tissue laterally
away from the margin of the preparation.

28
Q

Manipulation Of Impression
Materials

A

§ Hand mixing
§ Static mixing
§ Dynamic mechanical mixing

29
Q

This technique transforms two fluid (or paste-like) materials into a homogeneous
mixture without mechanical mixing

A

Static mixing

30
Q

Device uses motor to drive parallel plungers, forcing the materials
into a mixing tip and out into an impression tray or syringe.

A

Dynamic mechanical mixing

31
Q

Making the Impression - multible mix techniqe

A

Light body - syrenige
Heavy body- tray

32
Q

Multiple-mix technique

A

One step> light paste on the prepared tooth and over the tray which has the heavy body then take the impreasion by one step
2 steps > adhisve on the tray heavy body on the tray and take the ipressionn then place the light material on the prepared tooth then over the tray and take the impression again

33
Q

Monophase technique

A

Meduim body

Polyether and addition silicon

34
Q

Monophase mixing

A

Only one mixture is made and a part of the material is placed in
the tray and another portion in syringe for injection in the prepared tissues.—-> which will makes its viscisty to reduse and it will easliy flow over the teeth and tray

35
Q

Putty-wash technique

A

Condensation silicone
- To minimize the effect of associated dimensional changes .

36
Q

Removal of the impression

A

Remove after completly cured

Impression should be ready for removal within at least 10 min from time of mixing, allowing 6-8 min for impression to remain in mouth.

37
Q

Remove the impression

A

The first step: is to break the addhision between the impression and tray
Second step: stretch the impression to drive at the height of contour

38
Q

has the lowest viscosity and ranks as one of the least stiff of the elastomeric impression materials of a similar consistency.

A

Polysulfide

39
Q

All elastomeric impression materials are viscoelastic, and it is necessary to use a quick snap to minimize plastic deformation of the impression during the final step of the removal

A

Impo

Dm (5 decks)

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