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1 Elastomeric Impression Materials DA 122 Dental Materials

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Elastomeric Impression Materials

Elastomeric Impression MaterialsDA 122 Dental Materials#Elastomeric Impression MaterialsPolysulfidePolyetherPolyvinylsiloxane (known as addition silicone)All are supplied as2-paste systems (tubes): Base + catalystAutomix: Extruder guns (catalyst + base) with cartridge and mixing tipsBase and Catalyst are mixed to homogeneous consistencyBase = paste in tube, cartridge, or puttyCatalyst = paste in tube, cartridge, or liquid in bottle with dropper (AKA accelerator)Self-curing (chemical action)#Mixing elastomeric impression materialObjective when mixing elastomeric impression materials is:To obtain a homogenous mixTo obtain a uniform cure of the mix

Wear non-latex gloves#TubesBase and catalyst tubesNarrow stiff impression spatulaLarge mix pad (6X6)Syringe for light-body materialAdhesive-prepared tray for heavy-body material

#CartridgesLight-body cartridge with applicator tip or syringeHeavy-body cartridgeExtruder gun; one for each cartridge; hand-held or mechanical

#Automatic MixingMechanical device for mixing cartridges

Ex. MixStar Pentamix

#Putty-Polyvinyl SiloxaneAddition SiliconeBase = jar or bucketCatalyst = jar or liquidLarge mix pad (6X6)Narrow, stiff spatulaNon-latex glovesImpression trayPrepared with adhesive

#Curing StagesSelf-cure = polymerizationInitial set: includes mix and work time until material stiffens and you cannot manipulate itFinal set: in mouth; material goes from elasticity phase into rubber phaseFinal cure: takes place from 1 24 hours after final set; slight dimensional changes can occur#ViscositiesLight-bodied = syringe typewashThin body, can flow in and around tooth structureUsed in syringe or extruder gun and placed directly on tooth or structures in mouthRegular or heavy-bodied = tray typeThickerUsed to fill tray to make chairside custom tray which will hold light-bodied material against teeth for better detail#Polysulfide Impression MaterialCommon UsesFinal impressions for dentures and partial dentures

RATIO:Equal amountsMix to homogeneous consistencyCharacteristics:Known as rubber base or mercaptanUnpleasant odor (sulphur)Long setting timeStains clothing (mercaptan)Shrinkage after setting (disadvantage-lacks dimensional stability)Greater strength and tear resistance than colloidsFlexible

#PolysulfideArmamentariumStiff, narrow impression spatulaPaper mixing padCatalyst and base2x2 gauze squaresAdhesive-painted custom impression traySyringe to apply light-bodied materialClean-upOrange solvent2x2 gauze squaresWait until set to peel set material off spatulaRemove used sheet of mixing padRecap impression materials

MIX Surface: paper mixing padMIX instrument:Stiff, narrow spatula#PolysulfideTimesMix = 60 secondsWork = 3-6 minutesSet = 10 20 minutes in mouth

AppearanceShiny light blue or chocolate brownHomogenous end product

COMMON BRAND NAMES:PermlasticCoe-flexKerr#Polysulfide Impression material

#Polyether Impression MaterialCommon UsesFinal impression for crowns, bridges, indirect inlays or onlays

RATIO:Base : CatalystEqual amountsSpecial PropertiesAccuracyStabilityStiff enough to be used without putty on trayShorter working time#Polyether Impression MaterialArmamentariumImpression tray prepared with adhesiveNarrow, stiff spatula6x6 paper mix padBase and catalystSyringe for applicationClean-upWait until material sets and then peel it off of spatula or other non-porous surfacesWipe item clean with rubbing alcoholMIX surface: paper padMIX instrument: Narrow, stiff spatula**automatic mix units available **

#Polyether Impression MaterialTimes:Mix = 30 45 seconds

Work = 2 3 minutes

Set = 6 7 minutes in mouth

AppearanceShiny color

Common Brand Names:ImpregumPolyjel NF (we use)#Polyether Impression material

#Polyvinylsiloxane Impression Material (also known as addition silicone)Common UsesFinal Impressions: crowns, bridges, indirect inlays or onlays, implant crownsBite registrations

RATIO:equal amounts of base and catalystSpecial PropertiesAvailable in range of viscosities (bodies) or forms:Light, medium, heavy bodyHighly accurateEasy to spatulateOdor-freeTends to bubble on settingLatex gloves may inhibit set; use vinyl or nitrile gloves

#Polyvinylsiloxane Impression MaterialArmamentariumExtruder gun with CartridgeTipsAdhesive-prepared impression tray (custom or stock)Also available in automatic mix machineClean-upImmediately on porous surfaces; can stainWait to set to peel off non-porous surfaces

Mix surface/instrument:Not necessary because extruder gun is used

#Extruder gun dispenserExtruder gun dispenser for impression materials:Impression material moves plunger forward to force the:Base and accelerator from the individual chambersThen the pastes move into mixing tipThey blend and exit tip as a uniform paste#PolyvinylsiloxaneDisadvantage of polyvinylsiloxane (also known as silicone)ExpensiveShort shelf life#Polyvinylsiloxane Impression MaterialTimes:Mix = 30 seconds

Work = 2 minutes

Set = 5 minutes in mouthAppearance:Brightly colored, shiny, rubbery when set

Common Brand Names:Take 1ExpressPresident

#Techniques for Polyvinylsiloxane Wash TechniqueHeavy body + light body

Heavy body = putty in trayLight body=put in syringe


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