1. Impression Material

2. IMPRESSION MATERIALS, TYPES and TRAYS
Impression are negative reproduction of teeth and surrounding structure
Preliminary Impression
done by the assistant
poor dimensional stability
stock impressions trays
Final Impressions
done by the doctor only
good dimensional stability
stock impressions trays /custom trays

3. Preliminary Impression Material
Irreversible Hydrocolloid/Alginate
Thermo-dots
Polyvinylsiloxane Condensation material
Uses:
Diagnostic models
Opposing arch models
Fabrication of custom trays
Fabrication of provisional restorations

4. IMPRESSION TRAYS Full arch custom made preformed plastic
perforated rim lock
max/mand
Quadrant
Triple Tray
quadrant
sextant
take upper and lower in one
Sextant Tray
custom made
preformed plastic
perforated rim lock
ant/post

5. INITIAL IMPRESSIONS
Negative is poured in gypsum to create a positive model.
Models can be articulated together, articulator recreates the TMJ.
Models can be used as opposing for bite registration

6. FINAL IMPRESSIONS Negatives poured in gypsum to create positive model
Models are articulated together and the prep tooth is cut out of the model to create a die
A die is a replication of the prepared tooth or teeth or the edentulous mouth

7. CUSTOM TRAYS Acrylic light cured or self cured resin material
need a polymer and monomer
polymerization = setting

8. CUSTOM TRAYS Vacuum formed custom trays
resin sheets are heated and formed over the initial impression using heat and vacuum

9. CUSTOM TRAYS Thermoplastic tray material
beads or buttons that are pliable when heated

10. Preformed rim lock
Locks impression material into tray

11. Preformed Plastic
Need tray adhesive

12. Triple Trays
Takes final impression, opposing impression, and bite registration

13. CUSTOM TRAYS Acrylic resin tray Much like the thermoplastic beads
Needs spacer and stops because of the custom fit
Spacer can be pink wax, aluminum foil or wax paper

14. ELASTOMERIC MATERIALS
Rubberlike qualities
Used when precise duplication is needed
No distortion, great dimensional stability
Supplied in a two paste system
base and catalyst
Supplied in either a two tube system or extruder gun
Can be one or multiple body types

15. Polysulfide Advantages good stability,accuracy sharpness in detail
light = syringe, wash medium, heavy = tray material
long shelf life
used for crown, bridge, partial, denture impressions
Disadvantages
stains, tastes bad and stinks
ten minute setting time

16. Polyether Advantages excellent accuracy great dimensional stability
medium body only, used as both syringe and tray material
used for crown, bridge, denture and partial impressions
Disadvantages
only one body type

17. Silicone Polysiloxane Polyvinylsiloxane Condensation – putty
used for bite registration, custom tray
Polyvinylsiloxane
addition silicone
advantages
high degree of accuracy and dimensional stabilty
three body types
disadvantages
expensive

18. Bite Registration Polysiloxane bite registration material
open bite (shown)
closed bite
Wax bite registration material
pink wax
horseshoe wax
bees wax
aluwax

19. Preparation for Impression
Mix syringe material, deliver to provider
Mix tray material, place in tray and deliver to provider
Remove impression. disinfect and evaluate
Prepare provisional if necessary
Select material
Select type of tray or trays
Obtain an opposing arch, if necessary
Apply adhesive as directed to impression tray

20. What to send to Lab Lab slip Final Impression Opposing arch
Bite registration
It is important to give the lab tech everything they will need to produce a quality product

21. Deliver Appointment
Prosthetic should be due two days before appointment.
Any adjustments can be done outside the mouth before cementation or placement
Final adjustment of cemented appliance can be done in the mouth
Oral hygiene instructions