Elastomeric impression materials
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Elastomeric Impression Materials. DA 122 Dental Materials. Elastomeric Impression Materials. Polysulfide Polyether Polyvinylsiloxane (known as addition silicone ) All are supplied as 2-paste systems (tubes): Base + catalyst

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Elastomeric Impression Materials

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Elastomeric impression materials

Elastomeric Impression Materials

DA 122 Dental Materials


Elastomeric impression materials1

Elastomeric Impression Materials

  • Polysulfide

  • Polyether

  • Polyvinylsiloxane (known as addition silicone)

    • All are supplied as

      • 2-paste systems (tubes): Base + catalyst

      • Automix: Extruder guns (catalyst + base) with cartridge and mixing tips

    • Base and Catalyst are mixed to homogeneous consistency

      • Base = paste in tube, cartridge, or putty

      • Catalyst = paste in tube, cartridge, or liquid in bottle with dropper (AKA “accelerator”)

    • Self-curing (chemical action)


Mixing elastomeric impression material

Mixing elastomeric impression material

  • Objective when mixing elastomeric impression materials is:

    • To obtain a homogenous mix

    • To obtain a uniform cure of the mix

    • Wear non-latex gloves


Tubes

Tubes

  • Base and catalyst tubes

  • Narrow stiff

    impression spatula

  • Large mix pad (6X6)

  • Syringe for light-body

    material

  • Adhesive-prepared

    tray for heavy-body

    material


Cartridges

Cartridges

  • Light-body cartridge with

    applicator tip or

    syringe

  • Heavy-body

    cartridge

  • Extruder gun; one

    for each cartridge;

    hand-held or mechanical


Automatic mixing

Automatic Mixing

  • Mechanical device for

    mixing cartridges

    Ex. MixStar

    Pentamix


Putty polyvinyl siloxane addition silicone

Putty-Polyvinyl SiloxaneAddition Silicone

  • Base = jar or bucket

  • Catalyst = jar or liquid

  • Large mix pad (6X6)

  • Narrow, stiff spatula

  • Non-latex gloves

  • Impression tray

    • Prepared with adhesive


Curing stages

Curing Stages

  • Self-cure = polymerization

  • Initial set: includes mix and work time until

    material stiffens and you cannot manipulate

    it

  • Final set: in mouth; material goes from elasticity phase into rubber phase

  • Final cure: takes place from 1 – 24 hours after final set; slight dimensional changes can occur


Viscosities

Viscosities

  • Light-bodied = syringe type

    • “wash”

    • Thin body, can flow in and around tooth structure

    • Used in syringe or extruder gun and placed directly on tooth or structures in mouth

  • Regular or heavy-bodied = tray type

    • Thicker

    • Used to fill tray to make chairside custom tray which will hold light-bodied material against teeth for better detail


Polysulfide impression material

Polysulfide Impression Material

Common Uses

Characteristics:

Known as “rubber base” or mercaptan

Unpleasant odor (sulphur)

Long setting time

Stains clothing (mercaptan)

Shrinkage after setting (disadvantage-lacks dimensional stability)

Greater strength and tear resistance than colloids

Flexible

  • Final impressions for dentures and partial dentures

  • RATIO:

    • Equal amounts

    • Mix to homogeneous consistency


Polysulfide

Polysulfide

Armamentarium

Clean-up

Orange solvent

2x2 gauze squares

Wait until set to peel set material off spatula

Remove used sheet of mixing pad

Recap impression materials

MIX Surface: paper mixing pad

MIX instrument:

Stiff, narrow spatula

  • Stiff, narrow impression spatula

  • Paper mixing pad

  • Catalyst and base

  • 2x2 gauze squares

  • Adhesive-painted custom impression tray

  • Syringe to apply light-bodied material


Polysulfide1

Polysulfide

Times

Appearance

Shiny light blue or

chocolate brown

Homogenous end product

COMMON BRAND NAMES:

Permlastic

Coe-flex

Kerr

  • Mix = 60 seconds

  • Work = 3-6 minutes

  • Set = 10 – 20 minutes in mouth


Polysulfide impression material1

Polysulfide Impression material


Polyether impression material

Polyether Impression Material

Common Uses

Special Properties

Accuracy

Stability

Stiff enough to be used without putty on tray

Shorter working time

  • Final impression for crowns, bridges, indirect inlays or onlays

  • RATIO:

    • Base : Catalyst

    • Equal amounts


Polyether impression material1

Polyether Impression Material

Armamentarium

Clean-up

Wait until material sets and then peel it off of spatula or other non-porous surfaces

Wipe item clean with rubbing alcohol

MIX surface: paper pad

MIX instrument:

Narrow, stiff spatula

**automatic mix units available **

  • Impression tray prepared with adhesive

  • Narrow, stiff spatula

  • 6x6 paper mix pad

  • Base and catalyst

  • Syringe for application


Polyether impression material2

Polyether Impression Material

Times:

Appearance

Shiny color

Common Brand Names:

Impregum

Polyjel NF (we use)

  • Mix = 30 – 45 seconds

  • Work = 2 – 3 minutes

  • Set = 6 – 7 minutes in mouth


Polyether impression material3

Polyether Impression material


Polyvinylsiloxane impression material also known as addition silicone

Polyvinylsiloxane Impression Material (also known as addition silicone)

Common Uses

Special Properties

Available in range of viscosities (“bodies”) or forms:

Light, medium, heavy body

Highly accurate

Easy to spatulate

Odor-free

Tends to bubble on setting

Latex gloves may inhibit set; use vinyl or nitrile gloves

  • Final Impressions: crowns, bridges, indirect inlays or onlays, implant crowns

  • Bite registrations

  • RATIO:

    • equal amounts of base and catalyst


Polyvinylsiloxane impression material

Polyvinylsiloxane Impression Material

Armamentarium

Clean-up

Immediately on porous surfaces; can stain

Wait to set to peel off non-porous surfaces

Mix surface/instrument:

Not necessary because extruder gun is used

  • Extruder gun with

    • Cartridge

    • Tips

  • Adhesive-prepared impression tray (custom or stock)

  • Also available in automatic mix machine


Extruder gun dispenser

Extruder gun dispenser

  • Extruder gun dispenser for impression materials:

    • Impression material moves plunger forward to force the:

      • Base and accelerator from the individual chambers

      • Then the pastes move into mixing tip

      • They blend and exit tip as a uniform paste


Polyvinylsiloxane

Polyvinylsiloxane

  • Disadvantage of polyvinylsiloxane (also known as silicone)

    • Expensive

    • Short shelf life


Polyvinylsiloxane impression material1

Polyvinylsiloxane Impression Material

Times:

Appearance:

Brightly colored, shiny, rubbery when set

Common Brand Names:

Take 1

Express

President

  • Mix = 30 seconds

  • Work = 2 minutes

  • Set = 5 minutes in mouth


Techniques for polyvinylsiloxane

Techniques for Polyvinylsiloxane

Wash Technique

  • Heavy body + light body

  • Heavy body = putty in tray

  • Light body=put in syringe


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