final impressions anas laheq

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final impressions anas laheq

  1. 1. Final Impressions for Complete Dentures
  2. 2. Polyvinyl Siloxanes Addition Reaction Silicone • Hydrophobic • Newer materials more hydrophilic – Similar to Polysulfides & Polyethers • Flow – Thixotropic – Require pressure to flow
  3. 3. Polyvinyl Siloxanes Addition Reaction Silicone • Good dimensional stability • Excellent elastic recovery • Excellent dimensional accuracy • Material of choice
  4. 4. Wax Spacer Removal • After border molding, remove wax spacer • Do not dislodge border molding
  5. 5. Custom Trays • Smooth sharp surfaces of border molding or tray
  6. 6. Effect of Sharp Borders
  7. 7. Custom Trays • Place holes in tray to allow release of hydraulic pressure
  8. 8. Adhesive • Paint inside of tray & border molding • Allow to dry 7-15 minutes
  9. 9. Final Impressions • Dry tissues with 2x2 gauze folded in cotton pliers
  10. 10. Tissue Rest • Leave dentures out 24 hours – Tissue recovery • Use low viscosity polyvinyl siloxane material – Use adhesive
  11. 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. 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. 13. Tissue Manipulation Maxilla • Slight manipulation of cheeks, lips • Patient moves mandible to side to side for maxillary impression
  14. 14. Tissue Manipulation Mandible • Hold tray in position & have patient: – Pucker lips – Lift & move tongue forward & side to side
  15. 15. Impressions Videos Final Impressions Two Mirror Impression Technique
  16. 16. Set Time • Most polyvinyl siloxane materials set within 6 minutes
  17. 17. Evaluating Impression Video
  18. 18. Post-palatal Seal • Compensates for polymerization shrinkage away from palate • Enhances retention
  19. 19. Post-palatal Seal • Mark post-palatal seal with indelible stick – Glandular area & vibrating line • Place impression in mouth, line transfers to impression
  20. 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. 21. Boxing Final Impressions Rationale • Superior hardness of cast surface • Provides land area & preserves peripheral role • Minimizes trimming
  22. 22. Trimming the Cast
  23. 23. Trimming the Cast Land Area = 4mm Wide
  24. 24. Boxing Impression Video

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