elastomeric imp.pptx

8/19/2019 elastomeric imp.pptx

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ELASTOMERICIMPRESSION

MATERIALS


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Elastomeric Impression

Materials


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ADA specifcation number 19

Non aqueous elastomeric dental impression

material.Liquid polymers which can convert to solid

rubber at room temperature , by mixin asuitable catalyst

!ubber base or rubber impression material"lastomers or elastomeric impression material


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Elastomeric =

Rubber-like polymers tat so! anelastic bea"ior at te time o# loa$

application

#hese polymer molecules

have wea$ interaction in

between (Van der Wall forces), althouh they are tiedtoether in 3D networ$.

%n stretchin (on loading) chainsuncoil

At rest (o loading) chains snapbac$ C

e m

i c a

l N

a t u r e


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%i&er tear stren&t

More stable $imensionally instora&e

(No Synersis, Imbibation or Evaporation)

Ability to be electroplate$

'ut( )uite E*pensi"e ++++nco

mparso

n

o

y $

r o c o l l o i

$ s


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t y p e s


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#

o r m s

Materials’Consistency

Light

Medium

Heavy

PuttySilicone materials only


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&eneral 'eatures o' elastomeric

impressions"xcellent reproduction o' details

(ydrophobic

&ood elastic recovery

Dimensionally stable

&ood tear strenth


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)ses*mpression in fxed partial denture cases

*mpression o' dentulous and edentulous

arches+ite reistration

+order moldin o' special trays

Duplicatin material.


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Polysul.$e RubberImpression Material


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C%EMISTR/

A0 Composition1

Base paste1. LMW Polysulfide with two terminal and one pendant

SH groups

2. Fillers (Titanium dioxide)3. Plasticizer (Dibutyl phethalate)

Catalyst paste

1. Lead dioxide (rown) or organic peroxides (!ray) reactor 2. Fillers (Titanium dioxide)3. Plasticizer (Dibutyl phethalate)

R u

b b e

r


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R u

b b e

r

B. Setting eaction!

Condensation poly"erization(exothermi" # shrin$age) #it$

releasing of %2& as reaction

'y(product

)t occurs as a series of si"pleoxidation reactions

&xidation of ter"inal S%

groups poly"er c$ains

&xidation of pendent S%

groups Cross(lin*ing


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Material sets +ia condensation poly"erization

reaction

Water is t$e reaction 'y(product ,+aporation of #ater - poly"erization s$rin*age

i"ensional c$anges in storage

Water could cause air 'u''les in stone cast

Polysulfide is $ydrop$o'ic/ and can 'e electroplated

Lead dioxide is toxic and $as 'ad s"ell/ so it

$as 'een replaced in recent products 'y

peroxide co"pounds

R u

b b e

r

O'2IO3S C%ARACTERS


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Con$ensation Silicone

Impression Material


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C%EMISTR/

A0 Composition1

Base paste

1. LMW silicone poly"er with terminal OH groups2. Fillers (%olloidal sili"a or titanium dioxide) (white)

Catalyst paste1. 0l*yl silicate (%ross lin$ing)

2. in dilaurate or Stannous octoate (&"tivator)

S i l i c o n

e


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B. Setting eaction!

Condensation poly("erization (exothermi" # shrin$age)

releasing C2%&% as reaction 'y(product

)t occurs as a series of cross(lin*age of siloxane poly"er

to al*yl silicate in presence of t$e acti+ator/ to for" a 3D

poly"er net#or*

S i l i c o n

e


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Material sets +ia condensation poly"erization

reaction

,t$yl alco$ol is t$e reaction 'y(product ,+aporation of alco$ol - poly"erization s$rin*age

i"ensional c$anges in storage t$at of polysulfide 0lco$ol could cause air 'u''les in stone cast

Cond. silicone is $ydrop$o'ic/ and can 'e electroplated

eit$er #it$ sil+er or copper

S i l i c o n

e

O'2IO3S C%ARACTERS


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A$$ition SiliconesImpression Materials


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A $ $ i t i o n

S i l i c o n e s

C%EMISTR/

A0 Composition1

Base paste1. Poly "et$yl $ydrogen siloxane (Hydried or silane

terminated sili"one)

2. &t$er Siloxane pre(poly"ers

3. Fillers

Catalyst paste1. i+inyl poly4di"et$yl siloxane52. Platinu" salt acti+ator (%hloroplatini" a"id)

3. Siloxane pre(poly"ers

6. Fillers


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B. Setting eaction!

0ddition poly"erization (exothermi" # shrin$age) #it$ no

release of 'y(product

)t occurs as a series of cross(lin*age 'et#een +inyl(

ter"inated silicon and silane(ter"inated (hydried) silicon

"olecules/ in presence of t$e catalyst ( platinum salt ) to

for" a 3D poly"er net#or*

0 side reaction (Releasing hydrogen gas Air bubbles ingypsum cast) "ay occur if !

1. No balance between vinyl siloxane and the hydried silicone

2. Moisture react with hydrides o the base polymer

0dding no'le "etal (platinum or palladium) to t$eco"position #ill act as $ydrogen a'sor'er

A $ $ i t i o n

S i l i c o n e s


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0dding surfactants (sur'a"e tension redu"ingagents) to t$e co"position of add. silicone $elpturns t$e "aterial to 'e $ydrop$ilic (water lover)

0d+antages!

1. !etter wetting o sot tissue registration o better details

2. ↓ Air bubbles in gypsum cast

isad+antages!1. "iicult to be electroplated

2. #etting reaction could be retarded in presence o sulur (inlatex gloves) or sulate compounds (in gingival retra"tion"ords)

%/4ROP%ILIC SILICONE

A $ $ i t i o n

S i l i c o n e s


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Material sets +ia 0ddition poly"erization reaction (Nobyprodu"t) More di"ensionally sta'le t$ancondensation(poly"erized "aterials

%ydrogen gas "ay release fro" a side reaction inpresence of "oisture or i"'alance of t$e reactants.But, adding noble metal to the "omposition prevents therelease o' hydrogen gas no air bubbles in the gypsum"ast

0dd.silicone is $ydrop$o'ic and can 'eelectroplated/ $o#e+er adding of surfactants turnst$e "aterial $ydrop$ilic

A $ $ i t i o n

S i l i c o n e s

O'2IO3S C%ARACTERS


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Polyeter RubberImpression Material


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C%EMISTR/

A0 Composition1

Base paste1. LMW polyet$er with terminal imine groups

2. Filler ("olloidal sili"a)2. Plasticizer (dibutyl phethalate or gly"oether)

Catalyst paste

1. 0ro"atic sulfonate reactor (Sul'oni" a"id ester)2. Fillers

3. Plasticizer

P o

l y e

t e r R u

b b e r


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C%,M)S7

B. eaction! 4Cont.d5 Material sets +ia ring opening addition poly(

"erization reaction (No byprodu"t) of i"ine(ter"inated polyet$er #it$ t$e aro"atic sulfonate

L)8%(C9, P&L7,%, )t is 'ased on polyetherurethane dimetha"rylate/

photoinitiator , a""elerator $ and sili"one 'iller (hasreractive index similar to resin that helps inmaximi%ing the depth o curing)

$is "aterial is no longer 'e used P o

l y e

t e r R u

b b e r


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Material sets +ia 0ddition poly"erization reaction(No byprodu"t) More di"ensionally sta'le t$ancondensation poly"erized "aterials

Set "aterial is so stiff (as a result o' high rate o'

"rosslin$ing)/ so tray ad$esi+e "ust 'e used toretain t$e "aterial #it$in t$e tray at t$e ti"e ofre"o+ing an i"pression

Polyet$er is $ydrop$ilic and can a'sor' #ater in

#et condition 4s#elling5/ accordingly Can not be electroplated should be stored in dry environment to preserve its

dimensional accuracy

O'2IO3S C%ARACTERS

P o

l y e

t e r R

u b b e r


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Comparati"e Properties

o# Elastomeric ImpressionMaterials


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Biological properties!

1. Lead dioxide 4polysulfide5 is toxic/ 'ut follo#ingt$e "anufacturer:s instruction #ill decrease t$is

ris*

2. 0lco$ol 'y(product 4cond. Silicone5 is irritant to

oral soft tissues

3. 0ro"atic sulfonate 4polyet$er5 is irritant/ 'utproper "ixing #ill decrease t$is irrita'ilityo

mpara

"e

P r o p e r t i e s


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)nterfacial properties!

1. %ydrop$ilicity; &olysulide$ cond. #ilicone$ ' add. #ilicone are

hydrophobic ydrophilic silicone and polyether are ydrophilic

2. Co"pati'ility #it$ "odel and die "aterials... ydrophilic materials can not be electroplated &olysulide could be electroplated with silver $ while

silicones could be electroplated either with silver or copper

hydrophobic materials may cause air bubbles in stonecastso

mpara

"e

P r o p e r t i e s


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)nterfacial properties! (cont.d)

3. Separating "edia;here is no need (elastic materials) or separating

medium beore pouring the cast

6. etail reproduction; Although$ hydrophilic materials show better registration

o details than hydrophobic ones$ &olysulide is the bestdetail reproducer due to its higher low rate

o

mpara

"e

P r o p e r t i e s


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Mec$anical properties!

1. Flexi'ility...&olysulide *ond. #ilicone add. #ilicone polyether

2. Flo#...

&olysulide *ond.silicone &olyether Add. #ilicone

3. Per"anent defor"ation;&olysulide *ond.silicone &olyether Add. #ilicone

6. ear strengt$;&olyether polysulide silicones

. eco+ery;

Rubber materials are vis"oelasti" $ so impressions shouldbe poured +, min ater removal rom the patient mouth in

order to get the whole elastic and delayed recovery oimp.mat.

o

mpara

"e

P r o p e r t i e s


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C$e"ical properties!

1. i"ensional c$anges;*ond. silicone polysulide &olyether add silicone

All materials are associated with setting (polymeriation)shrin-age

All condensation polymeri%ed materials are less stable instorage as a result o evaporation o the reaction byproduct

2. &dor;

/ead dioxidecontaining polysulide has bad smell

P

r o p e r t i

e s


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Practica'ility!

1. Mixing ti"e... (0 sec. 1 min.)2. Wor*ing ti"e... (average min.)

3. Setting ti"e... (average 12 min)

6. Coast... higher than hydrocolloids

. S$elf life;storage in rerigerator elongate theshel lie


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Materials5 Manipulation

M a

n i p u l a t

i o n


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Mixing!

1. 9sing paper pad (!lass slab) and Spatula

/ight$ medium and heavy consistencies

2. %and =neadingeavy or putty consistency

3. 0uto"ixer and ispenser

*artridge orm only (/ight$ medium$ heavy)

6. 0uto"atic "ixing

All consistencies$ special electric mixer 4 special material orm M a

n i p u l a t

i o n


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M a

n i p u l a t

i o n


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rays!

1. Stoc* tray....5sed with heavy and putty consistency.Retention come through6 tray perorations$ rim loc-s$ or tray

adhesive

2. Special tray;.5sed with light and medium consistency.Retention comes rom6 tray perorations and tray adhesive

3. Was$ i"pression....#ome times heavy or putty impressions act as special tray or

light consistency material M a

n i p u l a t

i o n


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9ses!

1. )"pression "a*ing... *opper ring impression

Monophase impression

"ouble mix single phase impression

"ouble mix double phase impression (overwash impression)

*losed mouthdouble arch impression

2. &cclusal 'ite registration;

A specially supplied rubber material is used or this purpose

(commonly cartridge orm)

M a

n i p u l a t

i o n


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/our Comments

are appreciate$

elastomeric imp.pptx

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