09. Final Impressions for CD
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Transcript of 09. Final Impressions for CD
Final Impressions for Complete Dentures
Polyvinyl Siloxanes Polyvinyl Siloxanes Addition Reaction SiliconeAddition Reaction Silicone
• Hydrophobic • Newer materials more hydrophilic – Similar to Polysulfides & Polyethers
• Flow– Thixotropic– Require pressure to flow
Polyvinyl Siloxanes Polyvinyl Siloxanes Addition Reaction SiliconeAddition Reaction Silicone
• Good dimensional stability• Excellent elastic recovery• Excellent dimensional
accuracy• Material of choice
Wax Spacer RemovalWax Spacer Removal
• After border molding, remove wax spacer
• Do not dislodge border molding
Custom TraysCustom Trays
• Smooth sharp surfaces of border molding or tray
Effect of Sharp BordersEffect of Sharp Borders
Custom TraysCustom Trays
• Place holes in tray to allow release of hydraulic pressure
AdhesiveAdhesive• Paint inside of tray &
border molding • Allow to dry 7-15 minutes
Final ImpressionsFinal Impressions
• Dry tissues with 2x2 gauze folded in cotton pliers
Tissue RestTissue Rest
• Leave dentures out 24 hours – Tissue recovery
• Use low viscosity polyvinyl siloxane material –Use adhesive
Tray InsertionTray Insertion
• Insert side of tray against commissure of mouth & rotating the tray into place while pulling outward on the commissure of the contralateral side
Subsurface VoidsSubsurface Voids
Tech.Tech. Dentist Dentist
AA BB CC TOTAL TOTAL
F-BF-B 33 22 11 66 EvenEven 44 33 66 1313 B-FB-F 66 44 33 1313____________________________________________________
TOTALTOTAL 1313 99 1010 32 32
Final ImpressionsFinal Impressions
• Seat tray front to back - use gauze over holes in tray
• Ensure tray is centered & properly oriented
Tissue ManipulationTissue ManipulationMaxillaMaxilla
• Slight manipulation of cheeks, lips • Patient moves mandible to side
to side for maxillary impression
Tissue ManipulationTissue ManipulationMandibleMandible
• Hold tray in position & have patient:– Pucker lips– Lift & move tongue
forward & side to side
Impressions Videos
Final ImpressionsTwo Mirror Impression Technique
Set TimeSet Time
• Most polyvinyl siloxane materials set within 6 minutes
Evaluating Impression Video
Post-palatal SealPost-palatal Seal
• Compensates for polymerization shrinkage away from palate• Enhances retention
Post-palatal Seal Post-palatal Seal
• Mark post-palatal seal with indelible stick – Glandular area & vibrating line
• Place impression in mouth, line transfers to impression
Post-palatal SealPost-palatal Seal• Disinfect• Refresh the line with new indelible stick• Prescribe a mechanical post-palatal seal• Pour impression in Type III stone (ie.
Microstone)
Boxing Final ImpressionsBoxing Final ImpressionsRationaleRationale
• Superior hardness of cast surface• Provides land area & preserves
peripheral role• Minimizes trimming
Trimming the CastTrimming the Cast
Trimming the CastTrimming the CastLand Area = 4mm WideLand Area = 4mm Wide
Boxing Impression Video