Impression Materials Miu

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    Material is introduced in the mouth in a plastic condition to set against the oral tissues. It is then removed from the mouth when hardened .

    21 3

    4 5 6

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    The set impression is a negative reproduction of the oral tissues.

    A positive reproduction is obtained bypouring a suitable model or die material into it.

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    Ideal Re uirements of anIdeal Re uirements of animpression materialimpression material

    1. Accuracy:. Accuracy:a restoration or an appliance fabricated in thea restoration or an appliance fabricated in thelaboratory cannot be more accurate than thelaboratory cannot be more accurate than theimpression from which the used model isimpression from which the used model is

    prepared.prepared.2. Biologically acceptable:. Biologically acceptable:

    An impression material should beAn impression material should be non-toxic, non-non-toxic, non-irritant and of acceptable odour and tasteirritant and of acceptable odour and taste ..

    33 . . It shouldIt should not be affected by the oral fluidsnot be affected by the oral fluids ..4.4. Easily manipulated Easily manipulated , with minimal equipment., with minimal equipment.5.5. It should have aIt should have a suitable wor in! timesuitable wor in! time to allowto allowfor placement of the impression material in thefor placement of the impression material in the

    tray and then insertion of the tray into the mouthtray and then insertion of the tray into the mouthbefore be!innin! of hardenin!.before be!innin! of hardenin!.

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    Accuracy of the impression materials"Accurac

    y of the impression materials"#.#. $i!h$i!h flow at the beginning flow at the beginning , i.e. the material must be, i.e. the material must be

    in a fluid or plastic state on insertion into the mouth,in a fluid or plastic state on insertion into the mouth, totorecord fine detailsrecord fine details ..

    %.%. Dimensionally accurate Dimensionally accurate "" shouldshould not expand, contractnot expand, contractor warpor warp durin! settin!durin

    ! settin! ..

    3.3. Dimensionally stable Dimensionally stable "" onon stora!estor

    a!e of the impression inof the impression inthe dental laboratory before pourin! the castthe dental laboratory before pourin! the cast

    4.4. &hould be&hould be elastic on removal from the mouthelastic on removal from the mouth so thatso thatundercuts can be recordedundercuts can be recorded without distortionwithout distortion of theof theimpression.impression.

    5.5. 'urin! removal from the mouth, it should be'urin! removal from the mouth, it should beadherent to the trayadherent to the tray ..

    (.(. Compatible with the gypsum productsCompatible with the gypsum products "" not need anot need a

    separatin! medium.separatin! medium.

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    Classification of Impression MaterialsClassification of Impression Materials

    I!"ccording to manner of setting#!I!"ccording to manner of setting#!1$1$ %hemical &irreversi'le$#%hemical &irreversi'le$#

    harden through a chemical reaction(harden through a chemical reaction( e)g)e)g) plaster impression(plaster impression(

    *inc o+ide and eugenol( alginate and ru''er 'ase impression*inc o+ide and eugenol( alginate and ru''er 'ase impression

    materials)materials)

    2$2$ ,hysical &reversi'le$#, hysical &reversi'le$# they set as a result of a change of temperature withoutthey set as a result of a change of temperature without

    chemical changes(chemical changes( e)g)e)g) agar agar( impression compound andagar agar( impression compound and

    impression wa+es)impression wa+es)

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    II. )ehavior after settin!"II. )ehavior after settin !"'ependin! on their'ependin! on their ability to re!ain theirability to re!ain theirori!inal shape after removal from theori!inal shape after removal from theundercuts.undercuts.

    #. Inelastic#. Inelastic impression materials e.!. wax,impression materials e.!. wax,*laster of *aris, +n eu!enol and impression*laster of *aris, +n eu!enol and impressioncompound. hey are used only when nocompound. hey are used only when noundercut exists.undercut exists.

    %. /lastic%. /lastic impression materials e.!.impression materials e.!.

    hydrocolloids and rubber impression materials.hydrocolloids and rubber impression materials.

    hey can be used whenhey can be used when undercut exists.undercut exists.

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    Impression 0aterialsIm pression 0aterials

    Inelastic Inelastic Elastic Elastic Plaster of Plaster of Impression Impression Zinc oxide Zinc oxide

    Paris Paris compoundcompound eugenol eugenol

    Hydrocolloids Elastomers Hydrocolloids Elastomers

    gar gar lginate gar gar lginate

    Polysulphide !ilicones Polyether Polysulphide !ilicones Polyether

    Condensation dditionCondensation ddition

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    According to uses According to uses

    EdetulousPatient

    Partialy edentulouspatient

    Plaster, impression compoundand Zinc oxide and eugenol,hydocolloids, rubbers

    Hydocolloids, rubbers

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    According to the Accuracy According to the Accuracy

    1ry Impression

    (stock tray)

    2ry Impression

    (special tray)ompound

    impression material

    !lginate impression

    material

    Plaster impressionmaterial

    Zinc oxide"eugenolimpression material

    !gar !gar impressionmaterial

    #ubbersimpressionmaterials

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    *laster of *aris*laster of *arisUsed for impression ofUsed for impression of edentulous patientsedentulous patients ..

    1omposition"1om position" powder 2 waterpowder 2 water"#"# ## Ca!$%."&'H'$Ca!$%."&'H'$ (( notnot and or improvedand or improved stonestone

    because"because"

    )ea*er+)ea*er+ So it will break during removal from the undercut and thus avoidsSo it will break during removal from the undercut and thus avoidsinjury to the patient and the fractured part can be reassembled accuratelinjury to the patient and the fractured part can be reassembled accuratel $i!her * ratio$i !her * ratio ,, which increases the flow at the beginning and thuswhich increases the flow at the beginning and thus

    records fine details.records fine details.

    ess exothermic heatess exothermic heat evolved during taking of the impressionevolved during taking of the impression ..'. ,odifiers+'. ,odifiers+66 47 8 66 47 8 %%&& 44 decreases the setting expansion and the setting timdecreases the setting expansion and the setting tim

    99 6666 #7 borax#7 borax as a retarder as a retarder

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    -. atural gums+-. atural gums+ Improve itsImprove its handlin! characteristicshandlin! characteristics . They. Theyincrease its cohesion and facilitate border moldingincrease its cohesion and facilitate border moldingof the impression.of the impression.

    %. /lavoring agent+%. /lavori ng agent+oreore acceptable to the patientacceptable to the patient , through, through

    agreeable taste.agreeable taste.

    0. Coloring materials+0. Colori ng materials+!istinguish the impression!istinguish the impression from the cast, whichfrom the cast, whichwill also be made of gypsum products.will also be made of gypsum products.

    1. Potato starch+1. Potato starch+

    To obtain theTo obtain the soluble plastersoluble plaster . "fter the impression. "fter the impressionis cast and hardened, it is soaked in hot water andis cast and hardened, it is soaked in hot water andthethe starch swellsstarch swells and the impression disintegratesand the impression disintegratesand will beand will be easy to removeeasy to remove ..

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    Accuracy of plaster impression "

    a)a) -aterial is-aterial is semi!fluid when insertedsemi!fluid when inserted into the mouthinto the mouthit hasit has e+cellent recordinge+cellent recording of the fine details)of the fine details)

    ')') TheThe dimensional changes on setting in the mouthdimensional changes on setting in the mouthare negligi'leare negligi'le due to anti!e+pansion additives)due to anti!e+pansion additives)

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    c.c. A plaster impressionA plaster impression fractures on removalfractures on removalfrom undercutsfrom undercuts and can be reassembled.and can be reassembled.

    e.e. Elasticity+ Elasticity+ )ein! inelastic, it will)ein! inelastic, it will not recordnot recordthe formthe form of the under cut.of the under cut.

    f.f. hen pourin! a plaster impression in plaster orhen pourin! a plaster impression in plaster orin stone, ain stone, a separating medium should beseparating medium should beused used , otherwise, the pores of the impression, otherwise, the pores of the impressionwill be filled with the cast material, and bothwill be filled with the cast material, and both

    will bewill be interloc ed and becomeinterloc ed and becomeinseparableinseparable . he film of separation should be. he film of separation should beas thin as possible, in order to avoid theas thin as possible, in order to avoid theinaccuracies. he use of a separatin! medium isinaccuracies. he use of a separatin! medium isconsidered a disadvanta!e since fine detailsconsidered a disadvanta!e since fine detailsmi!ht be obliterated.mi!ht be obliterated.

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    Impression compoundIm pression compound pplication+ pplication+

    #.#. :ull ;aws impression in edentulous mouth.:ull ;aws impression in edentulous mouth.

    %.%. Impression traysImpression trays3.3. *eripheral seal materials.*eripheral seal materials.4.4. &in!le impression with copper band for inlays and crowns.&in!le impression with copper band for inlays and crowns.

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    ypes"ypes"#- Impression compound = ype I>"#- Im pression compound = ype I>" 67ower fusing materials67ower fusing materialsa.a. /or/or recording prosthetic impressionsrecording prosthetic impressions ++ &uch as preliminary&uch as preliminary

    impressions of edentulous patients, supplied in sheetsimpressions of edentulous patients, supplied in sheetsabout 4-5 mm thic .about 4-5 mm thic .

    b.b. Peripheral seal materials Peripheral seal materials ..

    c.c. &upplied in stic form or cone shape for&upplied in stic form or cone shape for

    copper band impressionscopper band impressions for inlays and crownsfor inlays and crowns

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    2! Tray compound &Type II$#2! Tray compound &Type II$#(Higher fusing materials):(Higher fusing materials):

    .sed as.sed as traytray materials( which are sufficientlymaterials( which are sufficientlyrigid to support other impression materialsrigid to support other impression materials &wash impression$)&wash impression$)

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    Accuracy of impression compound"Accurac y of impression compound"a. /low+a. /low+ not sufficiently fluidnot sufficiently fluid to record all the fine details.to record all the fine details.

    ypeIypeI materials is %&' at (&)* but less than +& at -)*,materials is %&' at (&)* but less than +& at -)*,

    TypeIITypeII materials is - ' at (&)* but less than /' at -)*.materials is - ' at (&)* but less than /' at -)*.

    b. Dimensional accuracy and dimensional stability+b. Dimensional ac curacy and dimensional stability+'imensional chan!es'imensional chan!es durin! hardenin! are !reat?????durin ! hardenin! are !reat?????

    999 999

    $i!h coefficient of thermal expansion$i!h coefficient of thermal expansion

    .

    .

    0101 2n cooling during setting, there is considerable cooling2n cooling during setting, there is considerable coolingshrinkage.shrinkage.

    $eatin! the surface of the set material in a flame and$eatin! the surface of the set material in a flame andrema in! the impression minimi

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    Impression 1ompound should be castImpression 1ompound should be castmaximum within an hour???maximum within an hour??? ..

    666'istortion"666'istortion" 0101 6emoval from undercuts since they are6emoval from undercuts since they are plastic andand

    have certain percentage ofhave certain percentage of flow after settin! inflow after settin! inthe mouth.the mouth.

    /1/1 Stresses can be set up within the material,Stresses can be set up within the material,subse#uently distortion can occur during storage ofsubse#uently distortion can occur during storage ofan impression due toan impression due to [email protected] of these stresses .

    c.c. The material isThe material is non-elasticnon-elastic the most serious drawbackthe most serious drawbackof this material is that it drags and distorts when beingof this material is that it drags and distorts when beingremoved from an undercut area.removed from an undercut area.

    d. compatible with model d. compatible with model and die materialsand die materials and doand do

    not need a separating medium.not need a separating medium.

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    1onductivity"1onductivi ty" 1ompound has1ompound has poor thermal conductivity poor thermal conductivity

    ime must be allowed durin! eitherime must be allowed durin! eitherheatin! or coolin! to allow the dentalheatin! or coolin! to allow the dentalcompound to come to a uniformcompound to come to a uniform

    temperature.temperature.hese impression can be removed fromhese impression can be removed from

    the mouth,the mouth, re-softened and reinserted forre-softened and reinserted for

    any correctionsany corrections re:uired re:uired ....Accept additionsAccept additions to the impressionto the impression

    1an be1an be electroplated with copper.electroplated with copper.

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    inc 0+ide ugenol Impression"s two separate pastes"s two separate pastes

    ne paste called the base paste"ne paste called the base paste"+inc oxide B7.+inc oxide B7.Inert oil #57 to form a paste.Inert oil #57 to form a paste.$ydro!enated resin$ydro!enated resin ..

    !econd paste called the accelerator contains+ !econ d paste called the accelerator contains+il of cloves oril of cloves or /u!enol #%-#5/u!enol #%-#5 7.7.

    $il of cloves+$il o f cloves+ &ometimes used instead of the eu!enol, since it is&ometimes used instead of the eu!enol, since it is lesslessirritant irritant than eu!enol.than eu!enol.

    Cum rosin and oilsCum rosin and oils (57(57 ++ CivesCives bodybody andand coherencecoherence andandimpartsimparts thermoplastic propertiesthermoplastic properties to the set materials for easyto the set materials for easyremoval from the cast by softenin! it in hot water.removal from the cast by softenin! it in hot water.:iller tal :iller tal or aolin or diatomaceous earth to form a paste.or aolin or diatomaceous earth to form a paste.

    0oisture.0oisture. A very sli!ht amount ofA very sli!ht amount of moisture water moisture water is added to theis added to the

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    ManipulationManipulation

    etting Reaction#ettin g Reaction#n 0 n 0 2200 n &0 $ n &0 $

    n &0 $2 2 ugenoln &0 $2 2 ugenol n ugenolate 20n ugenolate 20 &7ase$&7ase$&"cid$ & alt$&"cid$ & alt$ %helation Reaction%helation Reaction

    8ithout 8ithout 22 00 ( i)e) if eugenol is completely( i)e) if eugenol is completelydehydrated 'efore mi+ing with n0 powder( thedehydrated 'efore mi+ing with n0 powder( the

    resulting paste will not harden)resulting paste will not harden)

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    Accuracy of

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    Point ofcomparison Plasterimpressionmaterials

    1)Form ofsupply

    ,owder /water

    59!55ml/199gm

    Impressioncompound

    Thermoplasticmaterial

    heets

    tic:s

    cones

    Zinc/ !ide "eugenol

    impressionmaterial

    2 pastessystem

    0r ,/;

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    #) $pplication

    8holeedentulous

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    %)

    Composition

    a$o %&1"2 H 2 '1 highest

    "p ratio

    high *lo

    2 +eak

    -ess

    *eeling o*heat e.ol.ed

    1/hermoplastic materials0

    axes natural resin

    2 *illers add

    body

    Plastici ers

    lubricants

    % coloringagent

    Paste 1 Paste 2

    345 Zn' 165 'il o*clo.es oreugenol165

    inert oil

    Hydroge

    natedresin

    765 8um rosinthermoplasticity

    9illers

    :oisture

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    &)

    'etting

    reaction

    0n mi+ingpowder water=

    %a 0 4)1/2 20 20

    %a 0 4)2 20

    ompound(hard)

    ompound(so*t)

    ;

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    I $ccuracy

    %)

    imensional

    accuracy

    Properties

    1) Flo*

    #) +lasticity

    &)

    imensionalsta,ility

    +cellent

    >on elastic

    ?racture can 'ereassem'led

    9)[email protected]+pansion

    hrin:agemay resultdoes notaffect

    accuracy

    Type II#[email protected] at 45B%[email protected] at 3AB%

    Type I# at 45B%[email protected]

    at 3A % [email protected]

    >on elastic

    Distortionon removalof undercuts

    9)[email protected]%ontraction

    Distortiondue torelease ofinternal

    stresses

    Eery good

    >on elastic

    Distortion

    hrin:age9)[email protected]

    ightemperaturecausedistortion

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    I $ccuracy

    Properties

    -)Compati,ility*ith Cast

    Incompati'leeparating

    medium

    ,otato

    starch

    %ompati'le %ompati'le

    .)

    $dhesion

    ith the tray

    %ompati'le'ecause ofthe addition

    of gum

    "dhesive

    &resin$

    "dhesive

    &resin oil$

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    II)

    0aste

    - .npleasant- Dehydratesthe softtissue

    III)Manipulation

    I ) $ddition

    asy

    Does notaccept

    addition

    - ,leasant

    asy

    "ccept

    addition

    %an 'eelectroplated

    - ,leasant

    asy

    "cceptaddition

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    lastic Impression -aterialslastic Im pression -aterials

    " ueous" ueous elastic impression materialselastic impression materials& ydrocolloids$& ydrocolloids$

    >on!a ueous>on!a ueous elastic impressionelastic impression

    materialsmaterials &ru''er 'ases$&ru''er 'ases$

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    Elastic Impression Materials

    Hydrocolloids

    !gar agar

    !lginate

    Elastomers

    Polysulphide

    $ilicon

    Polyether

    ondensation !ddition

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    $ol.ent and $olute

    $olutionsingle phase( whichsingle phase( whichmeans ameans a homogenoushomogenousmi+turemi+ture ( where the solute( where the solute

    e+ists as smalle+ists as smallmolecules or ions in themolecules or ions in thesolvent)solvent)

    olloids

    Emulsionheterogeneousheterogeneous two!phasetwo!phasesystem( a dispersed phasesystem( a dispersed phase

    of particles of at leastof particles of at leastsufficient si*e to 'e seensufficient si*e to 'e seenmicroscopically( dispersedmicroscopically( dispersedin a medium)in a medium)

    Hydrocolloids

    $

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    A. $G'H 1 I'&"A. $G'H 1 I'&"1olloids1olloids between these two extremes.between these two extremes.

    hetero!eneous two-phase system, li e suspensionsystem, li e suspensionparticle si, in a networphase, to form fibrils or chains of molecule>, in a networpattern, calledpattern, called brush heap structure ..A!!lomeration of the molecules of the dispersed phaseA!!lomeration of the molecules of the dispersed phase totoform chains of molecules in a networ pattern,form chains of molecules in a networ pattern,

    ;y ; y "" H eduction in temperatureeduction in temperature =reversible as in a!ar>, =reversible as in a!ar>,or aor a

    1hemical reaction1hemical reaction =irreversible as in al!inate>. =irreversible as in al!inate>.

    C l i f h d ll idC

    l i f h d ll id

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    Ceneral properties of hydrocolloidsCene ral properties of hydrocolloids

    ".

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    '. Dimensional changes after setting+'. Dimensional changes after setting+A !el can either loose or ta e up water.

    TheThe loss of waterloss of water is termedis termed synersis andandoccurs either by8occurs either by89vaporation.9vaporation.9xcruding of fluids.9xcruding of fluids.

    The upta e of water is called imbibition ,,synersis and imbibition of the !el should be avoided asthe former causes shrin a!e, and the latter results inswellin! and expansion.

    &tora!e media, such as"&tora!e media, such as" 1111 %7 potassium sulfate or%7 potassium sulfate or 6666 #BB7 relative humidity#BB7 relative humidity ,,

    reduce the dimensional changes.reduce the dimensional changes.The best results are obtained with 0 ' relative humidityThe best results are obtained with 0 ' relative humidity

    3storage in 0 ' relative humidity results in minimum3storage in 0 ' relative humidity results in minimum

    amount of shrinkage5.amount of shrinkage5.

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    -. Disinfection+-. Disinfection+:ydrocolloid impression must be poured within a short:ydrocolloid impression must be poured within a short

    time after removal from the mouthtime after removal from the mouth;; Disinfection should be relatively rapid Disinfection should be relatively rapid

    to prevent dimensional changest o prevent dimensional changes ..'isinfectant is sprayed on the exposedsurface ..

    TheThe impression should not be soa ed in theim pression should not be soa ed in thedisinfectantdisinfectant . Immediately wrap the impression in a. Immediately wrap the impression in adisinfectant soaked paper towel and place it in adisinfectant soaked paper towel and place it in asealed plastic bag for 0 minutes.sealed plastic bag for 0 minutes.

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    %. Compatibility with gypsum+%. Compatibility with gypsum+ =+

    This may beThis may be due to the presence of the water on theon thesurface of the hydrocolloid which affects the settingsurface of the hydrocolloid which affects the settingand surface properties of the gypsum castand surface properties of the gypsum cast

    rr due todue to thethe chemical composition of somechemical composition of somehydrocolloids which retard the settin!hydrocolloids which retard the settin! of gypsumof gypsum

    products. products.his disadvanta!e can be overcome by two ways"his disadvant a!e can be overcome by two ways"

    1111 $y immersing the impression in a solution containing an$y immersing the impression in a solution containing anaccelerator for the settin! of !ypsum products, beforeaccelerator for the settin! of !ypsum products, before

    pourin! the impressionpourin! the impression with the gypsum.with the gypsum.1111 $y$y incorporatin! a plaster hardener or accelerator ininthe hydrocolloid material by the manufacturer.the hydrocolloid material by the manufacturer.

    111111 he cast should not be left too long in contact with the impression. he set stone absorbs waterfrom the water-filled impression. he result is a

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    Point of

    comparison $gar agar

    1) Form ofsupply

    Fel in sealedcontainer orcollapsi'le

    tu'e

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    #) $pplication

    8holeedentulous

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    &)

    'etting

    reaction

    !gar agar(gel)

    !gar agar(sol)

    %

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    Point ofcomparison $gar agar

    1) Form of

    supply

    Fel in sealedcontainer or

    collapsed tu'e

    $lginate

    ,owder and

    water

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    #) $pplication

    8hole

    edentulous 2 $' %

    3 5 ater

    9illers

    8hole

    edentulous orammonium alginate125& It reacts ith

    calcium ions to gi.ecalcium alginate gel&

    2) Calcium sulfate 125& It releases aions to react ithalginate (reactor)&

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    %)

    Composition

    3) Trisodium phosphate 2%: It reacts ith a==

    to gi.e a (P4 %), to delay the gel

    *ormation, (retarder)4) Filler: diatomacous earth;45*orstrength

    ) Fluoride: /o impro.e the sur*ace o*the stone model by acceleratingsetting time&

    !) Fla"oring agents: /o make thematerial acceptable to the patient&

    #) Chemical indicator: /o change thecolor ith ph changes in order toindicate the di**erent stages inmanipulation&

    3) 8lycol0 dustless&

    ?) @isin*ectant agents&

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    &) 'etting

    reaction

    Agar agar(gel)

    Agar agar(sol)

    43°C100°C

    1) $etardation $eaction:

    /risodium phosphate =

    calcium sulphate

    alcium phosphate =

    $odium sulphate

    alcium sul*ate =

    Potassium alginate

    (sol)alcium !lginate=

    &gel$ ,otassium sulphate

    2) elation reaction

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    I $ccuracy $gar $lginate

    %)imensional

    accuracy

    Properties

    1) Flo*

    #) +lasticity

    &)imensional

    sta,ility

    +cellent

    lastic

    HC)[email protected]

    Im'i'itionand synersis

    %an record finedetails

    lastic HA)[email protected]

    >o dimensionalchanges

    Im'i'itionandsynersis

    >odimensionalchanges

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    .) $dhesion

    ith the tray

    -) Compati,ility

    *ith Cast

    Manipulation pecial e uipments >o pecial e uipments

    $ddition accept addition Does not accept addition0ear strength low used in 4!6mm in tray

    +lectroplating %an not 'e electroplated

    Dipped [email protected] 2 0 4

    pecialperforatedtray

    Removedeasily

    needs perforated stoc:tray

    Dipped [email protected] 2 0 4

    Removedeasily

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    Rubber impression materials

    :&+ polymers (liAuid) = #eactor

    $olid rubbers ith :&+

    • Polysulphide

    • $ilicon0• ondensation silicon

    • !ddition silicon

    • Polyether

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    Point ofcomparison

    Polysulphideru,,ers

    1) Form of

    supply

    'iliconPolyetherru,,ers

    $upplied as t o pastes system

    -ight

    #egular

    hea.y

    -ight#egular

    Hea.y

    Putty

    -ight

    #egular

    hea.y

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    #)

    $pplication8hole edentulous

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    %)Composition

    Paste 1

    Paste 2

    Polysulphideith $H

    terminal gp(liAuid)

    -ead oxide *orpolymeri ation

    9illers 1 6%5

    Paste 1

    Paste 2

    Polydimethylsiloxane ith'H terminal

    gp

    /in octoate

    Fillers

    Paste 1

    Paste 2

    -o :&+&polymer ithsilane gp

    hloroplatinicacid

    9illers

    Paste 1

    Paste 2

    Polyetherpolymer ithethylene amine

    gp

    !romaticsulphonicacid ester

    9illers

    Polysulphideru,,ers

    'ilicon Polyetherru,,ers

    Condensation

    'ilicon

    $ddition

    'ilicon

    Plastici ersto regulatethe .iscositySulfur aids

    the reaction

    #etarders

    'rthoalkylsilicate *orcross linking

    -iAuid0 diluent

    paste0thickening

    agent

    -o :&+&polymer ith.inyl gp

    9illers

    Plastici ers

    9illers

    Plastici ers

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    Manipulation

    Special tray ith adhesi!eSpecial tray ith adhesi!e

    E"ual length of the t o pastesE"ual length of the t o pastes

    2#$mm in thic%ness2#$mm in thic%ness inside the tray

    except for polyether due to its hi!h stiffness

    Polysulphide 'ilicon Polyether

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    I $ccuracy

    %)

    imensional

    accuracy

    Properties

    1) Flo*

    #) +lasticity

    &)

    imensional

    sta,ility

    Record fine details according toconsistency

    [email protected]

    9)[email protected]:age

    hould 'e cast within 1hr)

    y pru,,ers ilicon

    Polyetherru,,ers

    Condensation'ilicon

    $ddition'ilicon

    HH)[email protected] HC)[email protected]

    9)[email protected]:age

    9)[email protected]:age

    9)[email protected]:age

    hrin:age also occurs due to differences in temperatu'etween the mouth the room as well as 'y products)

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    I $ccuracy

    Properties

    -)Compati,ility*ith Cast

    %ompati'leDoes notneedsurfactantto improvetheweta'ility

    Incompati'leevolution of

    2

    %ompati'le

    .)

    $dhesion

    ith the tray

    >eeds adhesive

    Polysulphideru,,ers

    'ilicon Polyetherru,,ers

    Condensation'ilicon

    $ddition'ilicon

    urfactant is needed to improvetheir weta'ility

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    II) 0aste ulfur odour

    III) 0earstrength

    I )isinfection "electroplating

    igh

    %an 'e

    - ,leasant

    ;east

    %an 'e

    - ,leasant

    less

    Can not bebecause it ishydrophilic

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    http://www.dentalcompare.com/details/4280/PerfectIM---Blue-Velvet.html