final impressions anas laheq

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  • Final Impressions for Complete Dentures

  • Potential Impression MaterialsIrreversible Hydrocolloid Hydrophilic but viscous Stock tray distorts vestibular tissues

  • Potential Impression MaterialsZinc oxide & eugenol Fast setRigid (undercuts difficult), Poor taste

  • Potential Impression MaterialsPolysulfides Poor tastePoor dimensional stability Poor elastic recovery

  • Potential Impression MaterialsSilicones Addition reactionAcceptable tasteDimensionally stableElastic recovery

  • Potential Impression MaterialsPolyethers Poor tasteDimensionally stableElastic recoveryExpensive

  • Polyvinyl Siloxanes Addition Reaction SiliconeHydrophobic Newer materials more hydrophilic Similar to Polysulfides & PolyethersFlowThixotropicRequire pressure to flow

  • Polyvinyl Siloxanes Addition Reaction SiliconeGood dimensional stabilityExcellent elastic recoveryExcellent dimensional accuracyMaterial of choice

  • Wax Spacer RemovalAfter border molding, remove wax spacer Do not dislodge border molding

  • Custom TraysSmooth sharp surfaces of border molding or tray

  • Effect of Sharp Borders

  • Custom TraysPlace holes in tray to allow release of hydraulic pressure

  • AdhesivePaint inside of tray & border molding Allow to dry 7-15 minutes

  • Final ImpressionsDry tissues with 2x2 gauze folded in cotton pliers

  • Tissue RestLeave dentures out 24 hours Tissue recovery Use low viscosity polyvinyl siloxane material Use adhesive

  • Final ImpressionsEnough material to replace wax spacerLoad quickly - viscosityAvoid bubbles when loading tray

  • Final ImpressionsCover all border molding with impression material

  • Tray InsertionInsert side of tray against commissure of mouth & rotating the tray into place while pulling outward on the commissure of the contralateral side

  • Subsurface Voids

    Tech. Dentist


    F-B3216 Even43613 B-F64313__________________________


    Final ImpressionsSeat tray front to back - use gauze over holes in trayEnsure tray is centered & properly oriented

  • Tissue ManipulationMaxillaSlight manipulation of cheeks, lips Patient moves mandible to side to side for maxillary impression

  • Tissue ManipulationMandibleHold tray in position & have patient:Pucker lipsLift & move tongue forward & side to side

  • Impressions VideosFinal ImpressionsTwo Mirror Impression Technique

  • Set TimeMost polyvinyl siloxane materials set within 6 minutes

  • Evaluating Impression Video

  • Evaluation of BordersMaterial should not be more than l mm thick over border molding (otherwise it was not fully seated)

  • Final Impressions

  • Final Impressions

  • Final Impressions

  • Post-palatal SealCompensates for polymerization shrinkage away from palateEnhances retention

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

  • Post-palatal SealDisinfectRefresh the line with new indelible stickPrescribe a mechanical post-palatal sealPour impression in Type III stone (ie. Microstone)

  • Boxing Final ImpressionsRationaleSuperior hardness of cast surfaceProvides land area & preserves peripheral roleMinimizes trimming

  • Boxing ImpressionTrimming Alginate

  • Pour the Model

  • Trimming the Cast

  • Trimming the CastLand Area = 4mm Wide

  • Boxing Impression Video