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DENT 113 > L4 impression material > Flashcards

L4 impression material Flashcards

1
Q

Impression compound should be soft outside the mouth (___ temp) and gradually hardens in the mouth (lowers to ___ temp)

A

43° - 55°
37.5 - 38°

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2
Q
  • High fusing (soften at 70°C) used as custom tray
  • Used to take final impression
  • SOFT (b27)
  • No longer used in dentistry now due to its bad properties : prone to warping, unstable
A

TYPE II (TRAY COMPOUND)

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3
Q
  • Low fusing (soften at 45°- 55° C) used to record (primary impression and tracing)
  • HARD (b27)
  • Stick form - used for border molding (b27)
A

TYPE I (IMPRESSION COMPOUND)

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4
Q

IMPRESSION CMPD USES

A
  • Primary impression for EDENTULOUS PATIENTS.
  • Modeling or tracing of special acrylic tray
  • Support other impression material (tray for wash
    impression)
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5
Q

different forms of type 1 impression cmpds (4)

A

sheets
sticks
cylinders
cones

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6
Q

type i impression cmpds are capable of recording sharp grooves from ___ wide

A

0.2-4mm

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7
Q

type 1 impression cmpds are _____: Able to record soft tissues under compressed state due to high viscosity

A

mucocompressive material

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8
Q

can be used to extend/line the borders of the tray to copy the shape of the ORAL MUCOSA AND VESTIBULE

A

stick

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9
Q
  • Used for taking impressions of a single tooth
  • A hollow open-ended copper tube is used as a tray
A

COPPER RING TECHNIQUE

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10
Q

causes of warpage: (4)

A
  1. residual stress
  2. incomplete homogenous softening
  3. removal of impression matrial before complete hardenting
  4. delaying in pouring the impression
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11
Q
  • Tray customized for the patient
  • Not used anymore because acrylics and plastics are better and more stable
  • Not distorted at mouth temperature
  • Used for corrective wash impression by adapting soften compound on study model and border of denture area trimmed
  • Tray compound lacks dimensional stability and strength
    thus replaced by acrylics and plastics
A

TYPE II tray compound

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12
Q

viscosity of impression compounds

A

4000 pas (most viscous of impression material)
- 70x > impression plaster
- 100x > light body elastomers

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13
Q

Significance of tray cmpd

A

Limits degree of fine detail which can be recorded in
impression
Characterizes compound as a mucocompressive
impression material

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14
Q

disinfection of tray cmpd

A

immerse for 10mins in 2% alkaline glutaraldehyde solution, rinsed and pour

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15
Q

ada spec of zinc oxide eugenol (ZOE) impression paste

A

16

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16
Q

ZOE can be found in 2 forms of pastes:

A

○ Base (white)
○ Accelerator/Reactor/Catalyst (red)

17
Q

ZOE types of paste

A

type i - soft
type ii - hard

18
Q

[mucostatic/mucocompressive]

  • ZOE
  • Impression plaster
  • Impression paste
A

Mucostatic (Minimal soft tissue displacement)

19
Q

[mucostatic/mucocompressive]

Impression compound

A

Mucocompressive (Squishes soft tissue)

20
Q

classify acc to dental use [complete denture / dentulous mouth]

ZOE
Impression plaster
Impression compound

A

complete denture

21
Q

classify acc to dental use [complete denture / dentulous mouth]

Alginate
Rubber base impression

A

dentulous mouth

22
Q

ELASTOMERIC IMPRESSION MATERIALS

  • AKA RUBBER IMPRESSION MATERIAL
  • Rubber-like polymers that show an elastic behavior at
    the time of load application
A

elastomeric

23
Q

ELASTOMERIC IMPRESSION MATERIALS

  • Long chain of chemical repeating units that attach
    together to form the set mass (polymers)
24
Q

ELASTOMERIC IMPRESSION MATERIALS
- These polymer molecules have weak interactions in between
(_____ what force ____), although they are tied together in 3D
network

A

Van der Wall forces

25
TYPES OF ELASTOMERIC MATERIALS
1. polysulfide (hydrophobic) 2. silicones 3. polyether (hydrophilic)
26
[hydrophobic/philic] ALL impression materials are ____! If indicated HYDROPHILIC, an ADDITIVE is only added to make it _____
HYDROPHOBIC, PHILIC
27
part of elastomeric impression materials - In rubber impression material, after it sets there will ALWAYS be a by-product - Material sets via CONDENSATION POLYMERIZATION reaction - WATER is the reaction by-product
polysulfide rubber
28
polysulfide rubber of elastomeric impression materials ___ is toxic and has bad smell, so it has been replaced in the recent products by peroxide compounds
lead oxide
29
part of elastomeric impression materials - Material sets via CONDENSATION POLYMERIZATION reaction - ETHYL ALCOHOL is the reaction by-product > Alcohol could cause air bubble in the stone cast
condensation silicone
30
Condensation silicone is ____, and can be electroplated with either silver or copper
hydrophobic
31
part of elastomeric impression materials: - Material sets via ADDITION POLYMERIZATION reaction (no by-product) → more dimensionally stable than condensation polymerized materials - HYDROGEN GAS may release from a side reaction in presence of moisture or imbalance of reactants
additional silicone
32
Additional silicone is ____ and can be electroplated, however adding of surfactants turns the material ___
hydrophobic, hydrophilic
33
part of elastomeric impression materials: - Material sets via ADDITION POLYMERIZATION REACTION (NO BY-PRODUCT) → more dimensionally stable than condensation polymerized materials - Set material is so STIFF (as a result of high rate of crosslinking), so tray adhesive must be used to retain the material within the tray at the time removing an impression - once nagset, mahirap alisin
polyether rubber
34
Polyether rubber is ____ and can absorb water in wet condition (swelling), accordingly. - Cannot be electroplated - Should be stored in dry environment to preserve its dimensional accuracy
HYDROPHILIC
35
types of tray for elastomeric impression compounds [stock tray/special tray/ wash impression] - Used with heavy and putty consistency - Retention come through tray perforations, rim locks, or tray adhesive - Used to be small, medium, or large only
stock tray
36
types of tray for elastomeric impression compounds [stock tray/special tray/ wash impression] - Used with light and medium consistency - Retention comes from tray perforations and tray adhesive - Used in full-dentures
special tray
37
types of tray for elastomeric impression compounds [stock tray/special tray/ wash impression] - Sometimes heavy or putty impressions act as special tray for light
wash impression
38
Which characteristic makes Polyether rubber challenging to remove from the tray after setting?
too stiff due to high cross-linking
39
the elastomeric material has the highest tear strength
polyether

DENT 113 (5 decks)

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