Impression Materialswww.indiandentalacademy.com
www.indiandentalacademy.com*
www.indiandentalacademy.comINDIAN DENTAL ACADEMYLeader in continuing dental educationwww.indiandentalacademy.com
www.indiandentalacademy.com
Impression MaterialsNon-elasticElasticAqueous HydrocolloidsNon-aqueous ElastomersCondensationAdditionAgar (reversible)Alginate (irreversible)OBrien Dental Materials & their Selection 1997www.indiandentalacademy.com
www.indiandentalacademy.com*
OBrien Dental Materials & their Selection 1997www.indiandentalacademy.com
www.indiandentalacademy.com*
Impression MaterialsNon-elasticElasticAqueous hydrocolloidsAgarAlginateNon-aqueous elastomersPolysulfideSiliconesCondensationAdditionPolyether
www.indiandentalacademy.com
www.indiandentalacademy.com*
IndicationsDiagnostic castspreliminaryopposing Indirect reconstructionfixedremovableBite registration
Giordano Gen Dent 2000www.indiandentalacademy.com
www.indiandentalacademy.com*
Elastomeric Impression MaterialsViscoelasticphysical properties varyrate of loadingRapidly removedecreases permanent deformationchains recoil from a recoverable distanceincreases tear strength
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
Aqueous HydrocolloidsColloidal suspensionschains align to form fibrilstraps water in intersticesTwo formssolviscous liquidgelelastic solidPlaced intra-orally as solconverts to gelthermal or chemical process
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
Aqueous HydrocolloidsSemi-permeable membranespoor dimensional stabilityEvaporationSyneresisfibril cross linking continuescontracts with timeexudes waterImbibitionwater absorptionswells
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
Reversible Hydrocolloid (Agar)Indicationscrown and bridgehigh accuracyExampleSlate Hydrocolloid (Van R)
www.indiandentalacademy.com
www.indiandentalacademy.com*
CompositionAgarcomplex polysaccharideseaweedgelling agentBoraxstrength
Potassium sulfateimproves gypsum surfaceWater (85%)
OBrien Dental Materials & their Selection 1997www.indiandentalacademy.com
www.indiandentalacademy.com*
ManipulationGel in tubessyringe and tray material
www.indiandentalacademy.com
www.indiandentalacademy.com*
Manipulation3 chamber conditioning unit(1) liquefy at 100C for 10 minutesconverts gel to sol(2) store at 65Cplace in tray(3) temper at 46C for 3 minutesseat traycool with water at 13C for 3 minutesconverts sol to gel
OBrien Dental Materials & their Selection 1997www.indiandentalacademy.com
www.indiandentalacademy.com*
AdvantagesDimensionally accurateHydrophilicdisplace moisture, blood, fluidsInexpensiveafter initial equipmentNo custom tray or adhesivesPleasantNo mixing required
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
DisadvantagesInitial expensespecial equipmentMaterial prepared in advancedTears easilyDimensionally unstableimmediate poursingle castDifficult to disinfect
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
Irreversible Hydrocolloid (Alginate)Most widely used impression material Indicationsstudy modelsremovable fixed partial denturesframeworkExamplesJeltrate (Dentsply/Caulk)Coe Alginate (GC America)
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
CompositionSodium alginatesalt of alginic acidmucous extraction of seaweed (algae)Calcium sulfatereactor
Sodium phosphateretarderFillerPotassium fluorideimproves gypsum surface
OBrien Dental Materials & their Selection 1997www.indiandentalacademy.com
www.indiandentalacademy.com*
ManipulationWeigh powderPowder added to waterrubber bowlvacuum mixerMixed for 45 sec to 1 minPlace trayRemove 2 to 3 minutes after gelation (loss of tackiness)
Caswell JADA 1986www.indiandentalacademy.com
www.indiandentalacademy.com*
AdvantagesInexpensiveEasy to useHydrophilicdisplace moisture, blood, fluidsStock trays
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
DisadvantagesTears easilyDimensionally unstableimmediate pour single castLower detail reproductionunacceptable for fixed prosHigh permanent deformationDifficult to disinfect
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
Non-Aqueous ElastomersSynthetic rubbersmimic natural rubberscarce during World War IILarge polymerssome chain lengtheningprimarily cross-linking Viscosity classeslow, medium, high, puttymonophasic
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
OBrien Dental Materials & their Selection 1997www.indiandentalacademy.com
www.indiandentalacademy.com*
PolysulfideFirst dental elastomersIndicationscomplete dentureremovable fixed partial denturetissuecrown and bridgeExamplesPermlastic (Kerr)Omni-Flex (GC America)
www.indiandentalacademy.com
www.indiandentalacademy.com*
CompositionBasepolysulfide polymersfillersplasticizersCatalystlead dioxide (or copper)fillersBy-productwater
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
--SH HS---------------------SHHS-- S H
O = Pb = OHS
-S-S---------------S-S- S S
+ 3PbO + H2OPolysulfide ReactionOBrien Dental Materials & their Selection 1997www.indiandentalacademy.com
www.indiandentalacademy.com*
ManipulationAdhesive to trayUniform layer custom trayEqual lengths of pastesMix thoroughlywithin one minuteSetting time 8 12 minutesPour within 1 hour
www.indiandentalacademy.com
www.indiandentalacademy.com*
AdvantagesLower costcompared to silicones and polyethersLong working timeHigh tear strengthHigh flexibilityGood detail reproduction
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
DisadvantagesPoor dimensional stabilitywater by-productpour within one hoursingle pourCustom traysMessypaste-paste mixbad odormay stain clothingLong setting time
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
Condensation SiliconeIndicationscomplete denturescrown and bridgeExamplesSpeedex (Coltene/Whaledent)Primasil (TISS Dental)
www.indiandentalacademy.com
www.indiandentalacademy.com*
CompositionBasepoly(dimethylsiloxane)tetraethylorthosilicatefillerCatalystmetal organic esterBy-productethyl alcohol
Phillips 1996Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
Condensation Silicone Reactionmetal organic ester ethanolPhillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
ManipulationMix thoroughlypaste - pastepaste - liquidPutty-wash techniquereduces effect of polymerization shrinkagestock trayputty placedthin plastic sheet spacerpreliminary impressionintraoral custom trayinject wash material
www.indiandentalacademy.com
www.indiandentalacademy.com*
AdvantagesBetter elastic propertiesClean, pleasantStock trayputty-washGood working and setting time
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
Disadvantages
Poor dimensional stabilityhigh shrinkagepolymerizationevaporation of ethanol pour immediatelywithin 30 minutesHydrophobicpoor wettability
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
Addition SiliconesAKA: Vinyl polysiloxaneIndicationscrown and bridgedenturebite registrationExamplesExtrude (Kerr)Express (3M/ESPE)Aquasil (Dentsply Caulk)Genie (Sultan Chemists)Virtual (Ivoclar Vivadent)
Click here for DIS evaluations of VPS impression materialswww.indiandentalacademy.com
www.indiandentalacademy.com*
CompositionImprovement over condensation siliconesno by-productFirst pastevinyl poly(dimethylsiloxane)prepolymerSecond pastesiloxane prepolymerCatalystchloroplatinic acid
Phillips 1996Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
Chloroplatinic Acid Catalyst
Addition Silicone ReactionPhillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
ManipulationAdhesive to tray Double mixcustom trayheavy-bodylight-body to prepPutty-washstock tray
Craig Adv Dent Res 1988www.indiandentalacademy.com
www.indiandentalacademy.com*
AdvantagesHighly accurateHigh dimensional stabilitypour up to one weekStock or custom traysMultiple castsEasy to mixPleasant odor
Phillips Science of Dental Materials 1996www.indiandentalacademy.com
www.indiandentalacademy.com*
DisadvantagesExpensiveSulfur inhibits set latex glovesferric and Al sulfateretraction solutionPumice teeth beforeimpressingShort working timeLower tear strengthPossible hydrogen gas releasebubbles on diepalladium added to absorb
Manikos Aust Dent J 1998www.indianden
