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Impression Material. 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 - PowerPoint PPT Presentation

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Impression Material

Impression MaterialIMPRESSION MATERIALS, TYPES and TRAYSImpression are negative reproduction of teeth and surrounding structurePreliminary Impression done by the assistantpoor dimensional stabilitystock impressions traysFinal Impressionsdone by the doctor onlygood dimensional stabilitystock impressions trays /custom traysPreliminary Impression MaterialIrreversible Hydrocolloid/AlginateThermo-dotsPolyvinylsiloxane Condensation materialUses:Diagnostic modelsOpposing arch modelsFabrication of custom traysFabrication of provisional restorationsIMPRESSION TRAYSFull archcustom madepreformed plasticperforated rim lockmax/mandQuadrantcustom madepreformed plastic perforated rim lock

Triple Trayquadrantsextanttake upper and lower in oneSextant Traycustom made preformed plasticperforated rim lockant/postINITIAL IMPRESSIONSNegative 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

FINAL IMPRESSIONSNegatives poured in gypsum to create positive modelModels are articulated together and the prep tooth is cut out of the model to create a dieA die is a replication of the prepared tooth or teeth or the edentulous mouth

CUSTOM TRAYSAcrylic light cured or self cured resin materialneed a polymer and monomerpolymerization = setting

CUSTOM TRAYSVacuum formed custom traysresin sheets are heated and formed over the initial impression using heat and vacuum

CUSTOM TRAYSThermoplastic tray materialbeads or buttons that are pliable when heated

Preformed rim lockLocks impression material into tray

Preformed Plastic Need tray adhesive

Triple TraysTakes final impression, opposing impression, and bite registration

CUSTOM TRAYSAcrylic resin trayMuch like the thermoplastic beadsNeeds spacer and stops because of the custom fitSpacer can be pink wax, aluminum foil or wax paper

ELASTOMERIC MATERIALSRubberlike qualitiesUsed when precise duplication is neededNo distortion, great dimensional stabilitySupplied in a two paste systembase and catalystSupplied in either a two tube system or extruder gunCan be one or multiple body typesPolysulfideAdvantagesgood stability,accuracysharpness in detaillight = syringe, wash medium, heavy = tray materiallong shelf lifeused for crown, bridge, partial, denture impressionsDisadvantagesstains, tastes bad and stinksten minute setting time

PolyetherAdvantagesexcellent accuracygreat dimensional stabilitymedium body only, used as both syringe and tray materialused for crown, bridge, denture and partial impressionsDisadvantagesonly one body type

SiliconePolysiloxaneCondensation putty used for bite registration, custom trayPolyvinylsiloxaneaddition siliconeadvantageshigh degree of accuracy and dimensional stabiltythree body typesdisadvantagesexpensive

Bite RegistrationPolysiloxane bite registration materialopen bite (shown)closed biteWax bite registration materialpink waxhorseshoe waxbees waxaluwax

Preparation for ImpressionSelect materialSelect type of tray or traysObtain an opposing arch, if necessaryApply adhesive as directed to impression tray

Mix syringe material, deliver to providerMix tray material, place in tray and deliver to providerRemove impression. disinfect and evaluatePrepare provisional if necessary

What to send to LabLab slipFinal ImpressionOpposing archBite registrationIt is important to give the lab tech everything they will need to produce a quality product

Deliver AppointmentProsthetic should be due two days before appointment. Any adjustments can be done outside the mouth before cementation or placementFinal adjustment of cemented appliance can be done in the mouthOral hygiene instructions

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