1. Elastomeric Impression Materials
DA 122 Dental Materials

2. 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)

3. 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

4. Tubes Base and catalyst tubes Narrow stiff impression spatula
Large mix pad (6X6)
Syringe for light-body
material
Adhesive-prepared
tray for heavy-body

5. Cartridges Light-body cartridge with applicator tip or syringe
Heavy-body
cartridge
Extruder gun; one
for each cartridge;
hand-held or mechanical

6. Automatic Mixing Mechanical device for mixing cartridges Ex. MixStar
Pentamix

7. Putty-Polyvinyl Siloxane Addition Silicone
Base = jar or bucket
Catalyst = jar or liquid
Large mix pad (6X6)
Narrow, stiff spatula
Non-latex gloves
Impression tray
Prepared with adhesive

8. 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

9. 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

10. Polysulfide Impression Material
Common Uses
Characteristics:
Final impressions for dentures and partial dentures
RATIO:
Equal amounts
Mix to homogeneous consistency
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

11. Polysulfide Armamentarium Clean-up Stiff, narrow impression spatula
Paper mixing pad
Catalyst and base
2x2 gauze squares
Adhesive-painted custom impression tray
Syringe to apply light-bodied material
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

12. Polysulfide Times Appearance Mix = 60 seconds Work = 3-6 minutes
Set = 10 – 20 minutes in mouth
Shiny light blue or
chocolate brown
Homogenous end product
COMMON BRAND NAMES:
Permlastic
Coe-flex
Kerr

13. Polysulfide Impression material

14. Polyether Impression Material
Common Uses
Special Properties
Final impression for crowns, bridges, indirect inlays or onlays
RATIO:
Base : Catalyst
Equal amounts
Accuracy
Stability
Stiff enough to be used without putty on tray
Shorter working time

15. Polyether Impression Material
Armamentarium
Clean-up
Impression tray prepared with adhesive
Narrow, stiff spatula
6x6 paper mix pad
Base and catalyst
Syringe for application
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 **

16. Polyether Impression Material
Times:
Appearance
Mix = 30 – 45 seconds
Work = 2 – 3 minutes
Set = 6 – 7 minutes in mouth
Shiny color
Common Brand Names:
Impregum
Polyjel NF (we use)

17. Polyether Impression material

18. Polyvinylsiloxane Impression Material (also known as addition silicone)
Common Uses
Special Properties
Final Impressions: crowns, bridges, indirect inlays or onlays, implant crowns
Bite registrations
RATIO:
equal amounts of base and catalyst
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

19. Polyvinylsiloxane Impression Material
Armamentarium
Clean-up
Extruder gun with
Cartridge
Tips
Adhesive-prepared impression tray (custom or stock)
Also available in automatic mix machine
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

20. 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

21. Polyvinylsiloxane
Disadvantage of polyvinylsiloxane (also known as silicone)
Expensive
Short shelf life

22. Polyvinylsiloxane Impression Material
Times:
Appearance:
Mix = 30 seconds
Work = 2 minutes
Set = 5 minutes in mouth
Brightly colored, shiny, rubbery when set
Common Brand Names:
Take 1
Express
President

23. Techniques for Polyvinylsiloxane
Wash Technique
Heavy body + light body
Heavy body = putty in tray
Light body=put in syringe