1. Final Impressions for
Complete Dentures

2. Polyvinyl Siloxanes
Addition Reaction Silicone
• Hydrophobic
• Newer materials more hydrophilic
– Similar to Polysulfides & Polyethers
• Flow
– Thixotropic
– Require pressure to flow

3. Polyvinyl Siloxanes
Addition Reaction Silicone
• Good dimensional stability
• Excellent elastic recovery
• Excellent dimensional
accuracy
• Material of choice

4. Wax Spacer Removal
• After border molding, remove
wax spacer
• Do not dislodge border molding

5. Custom Trays
• Smooth sharp surfaces of
border molding or tray

6. Effect of Sharp Borders

7. Custom Trays
• Place holes in tray to allow
release of hydraulic
pressure

8. Adhesive
• Paint inside of tray &
border molding
• Allow to dry 7-15 minutes

9. Final Impressions
• Dry tissues with 2x2 gauze
folded in cotton pliers

10. Tissue Rest
• Leave dentures out 24 hours
– Tissue recovery
• Use low viscosity polyvinyl
siloxane material
– Use adhesive

11. Tray Insertion
• Insert side of tray
against commissure of
mouth & rotating the
tray into place while
pulling outward on
the commissure of the
contralateral side

12. Final Impressions
• Seat tray front to
back - use gauze
over holes in tray
• Ensure tray is
centered &
properly
oriented
Subsurface Voids
Subsurface Voids
Tech.
Tech.
Dentist
Dentist
A
A
B
B
C
C
TOTAL
TOTAL
F-B
2
1
6
F-B 3
3
2
1
6
Even 4
3
6
13
Even 4
3
6
13
B-F
6
4
3
13
B-F
6
4
3
13
__________________________
__________________________
TOTAL 13
TOTAL 13
9
9
10
10
32
32

13. Tissue Manipulation
Maxilla
• Slight manipulation of
cheeks, lips
• Patient moves mandible to
side to side for maxillary
impression

14. Tissue Manipulation
Mandible
• Hold tray in position &
have patient:
– Pucker lips
– Lift & move tongue
forward & side to side

15. Impressions Videos
Final Impressions
Two Mirror Impression Technique

16. Set Time
• Most polyvinyl siloxane
materials set within 6
minutes

17. Evaluating Impression Video

18. Post-palatal Seal
• Compensates for
polymerization shrinkage
away from palate
• Enhances retention

19. Post-palatal Seal
• Mark post-palatal seal with indelible stick
– Glandular area & vibrating line
• Place impression in mouth, line transfers
to impression

20. Post-palatal Seal
•
•
•
•
Disinfect
Refresh the line with new indelible stick
Prescribe a mechanical post-palatal seal
Pour impression in Type III stone (ie.
Microstone)

21. Boxing Final Impressions
Rationale
• Superior hardness of cast surface
• Provides land area & preserves
peripheral role
• Minimizes trimming

22. Trimming the Cast

23. Trimming the Cast
Land Area = 4mm Wide

24. Boxing Impression Video