rubber impression material

RUBBER IMPRESSION RUBBER IMPRESSION MATERIALMATERIAL

RUBBER IMPRESSION MATERIALSRUBBER IMPRESSION MATERIALS

1.1. POLYSULFIDE RIMPOLYSULFIDE RIM

2.2. SILICONE RIMSILICONE RIM

A. A. CONDENSATION TYPECONDENSATION TYPE

B. B. ADDITION TYPEADDITION TYPE

3. 3. POLYETHER RIMPOLYETHER RIM

1. POLYSULFIDE RIM1. POLYSULFIDE RIM

PACKAGINGPACKAGING

Supplied as two pastes with one tube labeled Supplied as two pastes with one tube labeled CATALYST or ACCELERATOR and the other CATALYST or ACCELERATOR and the other marked BASE.marked BASE.

3 Types:3 Types:

a. light bodya. light body

b. regular bodyb. regular body

c. heavy bodyc. heavy body

COMPOSITIONCOMPOSITIONa. catalyst or acceleratora. catalyst or accelerator

1. Inert oil – 1. Inert oil – dibutyl or dioctyl phthalatedibutyl or dioctyl phthalate2. Most common catalyst – 2. Most common catalyst – lead dioxide lead dioxide

with or without manganese dioxide; copper with or without manganese dioxide; copper hydroxidehydroxideb. baseb. base

- 80% low molecular weight organic - 80% low molecular weight organic polymer containing reactive mercaptan groupspolymer containing reactive mercaptan groups

- 20% reinforcing agents- 20% reinforcing agentsa. titanium dioxidea. titanium dioxideb. zinc sulfateb. zinc sulfatec. copper carbonatec. copper carbonated. silicad. silica

SETTING REACTIONSETTING REACTION

Mercaptan + Lead dioxide Mercaptan + Lead dioxide Polysulfide + H20 Polysulfide + H20

• • reaction is reaction is sensitive to moisture and sensitive to moisture and temperaturetemperature. Increases in either one will accelerate . Increases in either one will accelerate the setting reaction. the setting reaction.

PROPERTIES:PROPERTIES:1.1. ToxicityToxicity

2.2. Color of the base & acceleratorColor of the base & accelerator

3.3. Time required for mixingTime required for mixing

4.4. Working timeWorking time

5.5. ConsistencyConsistency

6.6. Permanent deformation during removalPermanent deformation during removal

7.7. Dimensional stabilityDimensional stability

8.8. Flow after settingFlow after setting

9.9. FlexibilityFlexibility

10.10. Reproduction of detailReproduction of detail

11.11. Compatibility with die and model materialCompatibility with die and model material

12.12. Deterioration during storage of the unmixed material Deterioration during storage of the unmixed material

MANIPULATIONMANIPULATION

TWO-PASTE TYPETWO-PASTE TYPE

1.1. Equal lengths of the base & accelerator Equal lengths of the base & accelerator are are extruded onto a paper pad. extruded onto a paper pad.

2.2. A A tapered, stiff-bladed spatula tapered, stiff-bladed spatula is used in mixing is used in mixing the accelerator with the base for 5 to 10 seconds the accelerator with the base for 5 to 10 seconds in a in a circular motioncircular motion..

3.3. The blade of the spatula is wiped on the pad and The blade of the spatula is wiped on the pad and then with a paper towel – this procedure makes then with a paper towel – this procedure makes it easier to obtain a mix free from streaks later.it easier to obtain a mix free from streaks later.

4.4. The mixing is continued with a The mixing is continued with a wide sweeping wide sweeping motion until the mix is free from streaks and motion until the mix is free from streaks and uniform in coloruniform in color. The mixing should be . The mixing should be accomplished in about 45 seconds.accomplished in about 45 seconds.

5.5. If the material is If the material is light-bodied, it is loaded into a light-bodied, it is loaded into a syringe and is injectedsyringe and is injected into the cavity into the cavity preparation and the tray containing the heavy-preparation and the tray containing the heavy-bodied material is placed over the light-bodied bodied material is placed over the light-bodied material and the tray is seated.material and the tray is seated.

6.6. When the material has set, When the material has set, the impression is the impression is removed with a steady forceremoved with a steady force. A snap removal of . A snap removal of the impression is not possible or necessary since the impression is not possible or necessary since the tear strength of the polysulfides is much the tear strength of the polysulfides is much higher.higher.

7.7. After removal of the impression, it is After removal of the impression, it is checked checked for completeness and detail, is thoroughly for completeness and detail, is thoroughly cleaned by rinsing with tap water, then cleaned by rinsing with tap water, then disinfected and rinsed again with waterdisinfected and rinsed again with water. The . The excess water is shaken off and any residual excess water is shaken off and any residual moisture is removed by a gentle stream of air.moisture is removed by a gentle stream of air.

2. SILICONE RIM2. SILICONE RIM

PACKAGINGPACKAGING

Supplied in light-, regular-, heavy-bodied Supplied in light-, regular-, heavy-bodied consistency as well as a very heavy consistency consistency as well as a very heavy consistency called a PUTTY.called a PUTTY.

COMPOSITIONCOMPOSITION

2 Types:2 Types:

a. a. CONDENSATIONCONDENSATION

- supplied as a BASE & an - supplied as a BASE & an ACCELERATOR or CATALYSTACCELERATOR or CATALYST

- BASE contains- BASE contains

- moderately low-molecular weight - moderately low-molecular weight silicone liquid (silicone liquid (DIMETHYLSILOXANEDIMETHYLSILOXANE))

- SILICA – reinforcing agent- SILICA – reinforcing agent

- ACCELERATOR contains- ACCELERATOR contains

- tin organic ester suspension- tin organic ester suspension

- alkyl silicate (ortho-ethyl silicate)- alkyl silicate (ortho-ethyl silicate)

b. b. ADDITION (ADDITION (VINYL SILICONEVINYL SILICONE))

- supplied as a two-paste or a two-putty - supplied as a two-paste or a two-putty system with one containing a low-molecular system with one containing a low-molecular weight silicone having terminal vinyl groups, weight silicone having terminal vinyl groups, reinforcing filler and a chloroplatinic acid catalyst reinforcing filler and a chloroplatinic acid catalyst and the other containing a low-molecular weight and the other containing a low-molecular weight silicone having silane hydrogens and reinforcing silicone having silane hydrogens and reinforcing filler.filler.


CONDENSATION TYPECONDENSATION TYPE

Dimethylsiloxane + Ortho-ethyl silicate + tin octate Dimethylsiloxane + Ortho-ethyl silicate + tin octate

silicone rubber + ethyl alcoholsilicone rubber + ethyl alcohol

ADDITION TYPEADDITION TYPE

Hydrgen-containing siloxane + vinyl-terminal siloxane + Hydrgen-containing siloxane + vinyl-terminal siloxane + Chloroplatinic acid Silicone rubberChloroplatinic acid Silicone rubber

CONSISTENCIESCONSISTENCIES


Supplies as a:Supplies as a:

a. light-bodied – tubea. light-bodied – tube

b. putty-base material – jarb. putty-base material – jar

c. catalyst – tube either as a liquid or pastec. catalyst – tube either as a liquid or paste

ADDITION TYPEADDITION TYPESupplied as a:Supplied as a:

a. light-, medium-, or heavy-bodied base and a. light-, medium-, or heavy-bodied base and catalyst pastescatalyst pastes

b. base and catalyst putty (very heavy-bodied) b. base and catalyst putty (very heavy-bodied) – jar– jarPutty Putty consistencies are available as a soft- or regular-consistencies are available as a soft- or regular-set type.set type.The The light- to heavy-bodied light- to heavy-bodied materials and one materials and one manufacturer’s very heavy-bodied material are manufacturer’s very heavy-bodied material are available in a dual cartridge system called auto-mixing available in a dual cartridge system called auto-mixing systems.systems.Monophase materials Monophase materials – single-consistency material – single-consistency material that can be used as both a light- and a heavy-bodied that can be used as both a light- and a heavy-bodied material.material.

PROPERTIESPROPERTIES


1.1. Working time and setting time (6-8 minutes) is Working time and setting time (6-8 minutes) is shorter.shorter.

2.2. Viscosity is less thus easier mixing.Viscosity is less thus easier mixing.

3.3. Dimensional change during 24 hours after Dimensional change during 24 hours after setting is larger.setting is larger.

4.4. Permanent deformation is lowerPermanent deformation is lower

5.5. Flow values 1 hour after setting are much lower.Flow values 1 hour after setting are much lower.

6.6. Flexibility is also lower.Flexibility is also lower.

7.7. Materials are non-toxicMaterials are non-toxic

8.8. Readily reproduce fine details of the surface.Readily reproduce fine details of the surface.

9.9. Compatible with model plaster and high-Compatible with model plaster and high-strength stone.strength stone.

10.10. Wettability is poor.Wettability is poor.

11.11. Have reasonable shelf-life but is usually shorter.Have reasonable shelf-life but is usually shorter.

12.12. Tear strength is lower – about 17 lb/in (3000 Tear strength is lower – about 17 lb/in (3000 gm/cm)gm/cm)

ADDITION TYPEADDITION TYPE

1.1. Dimensional change is very lowDimensional change is very low

2.2. Permanent deformation is the lowest of all Permanent deformation is the lowest of all impression materialsimpression materials

3.3. Flow values is very lowFlow values is very low

4.4. Working time is shorterWorking time is shorter

5.5. Flexibility is lowerFlexibility is lower

6.6. Removal from undercut areas may present Removal from undercut areas may present difficulties because of its stiffnessdifficulties because of its stiffness

7.7. Causes less tissue reactionCauses less tissue reaction



1.1. The putty is dispensed with a scoop.The putty is dispensed with a scoop.

2.2. Depressions are made in the surface of the putty, Depressions are made in the surface of the putty, and the appropriate number of drops or the and the appropriate number of drops or the appropriate length of catalyst is added.appropriate length of catalyst is added.

3.3. A stiff spatula is used to mix the putty and liquid A stiff spatula is used to mix the putty and liquid or paste catalyst.or paste catalyst.

4.4. Once the catalyst is well incorporated, mixing Once the catalyst is well incorporated, mixing may be continued by hand for 30 seconds or may be continued by hand for 30 seconds or until free from streaks. The hands should be until free from streaks. The hands should be moist to prevent sticking.moist to prevent sticking.

5.5. The putty is placed in a perforated stock tray or The putty is placed in a perforated stock tray or an adhesive-treated nonperforated tray, and a an adhesive-treated nonperforated tray, and a preliminary impression is made before preparing preliminary impression is made before preparing the teeth.the teeth.

6.6. The impression tray is rocked to provide 1 to 2 The impression tray is rocked to provide 1 to 2 mm of space for the wash material, and the putty mm of space for the wash material, and the putty is allowed to set.is allowed to set.

7.7. After cavity preparation, the wash material is After cavity preparation, the wash material is mixed as is any syringe material, and the mixed as is any syringe material, and the material is injected into the impression area and material is injected into the impression area and sometimes into the putty impression area.sometimes into the putty impression area.

8.8. The tray, plus the putty impression, is inserted The tray, plus the putty impression, is inserted and held firmly until the wash material sets.and held firmly until the wash material sets.

ADDITION TYPEADDITION TYPE1.1. The two pastes of the light-, regular-, and heavy-The two pastes of the light-, regular-, and heavy-

bodied materials are dispensed onto a mixing bodied materials are dispensed onto a mixing pad in equal lengths and spatulated in the same pad in equal lengths and spatulated in the same manner as described for the polysulfides. manner as described for the polysulfides. Mixing time – 30 to 40 seconds.Mixing time – 30 to 40 seconds.

2.2. The base and catalyst putties are dispensed in The base and catalyst putties are dispensed in equal quantities and are mixed by hand until free equal quantities and are mixed by hand until free from streaksfrom streaks

3.3. Automix system Automix system – –

a. the cartridge is inserted into the gun and a. the cartridge is inserted into the gun and the cap on the end is removed.the cap on the end is removed.

b. the plungers are advanced by the trigger b. the plungers are advanced by the trigger until the base and catalyst paste are extruding until the base and catalyst paste are extruding uniformlyuniformly

c. the tip is wiped off and a static mixing c. the tip is wiped off and a static mixing tip is placed on the end of the cartridge.tip is placed on the end of the cartridge.

d. the trigger is used to extrude and mix d. the trigger is used to extrude and mix the base and catalyst through the mixing tip. The the base and catalyst through the mixing tip. The material is thoroughly mixed as it exits the tip.material is thoroughly mixed as it exits the tip.

3. POLYETHER RIM3. POLYETHER RIM

PACKAGINGPACKAGING

Supplied as a BASE & CATALYST system.Supplied as a BASE & CATALYST system.

COMPOSITIONCOMPOSITION

BASE – moderately low-molecular weight BASE – moderately low-molecular weight polyether, containing ethylene imine terminal polyether, containing ethylene imine terminal groups.groups.

CATALYST – aromatic sulfonic acid esterCATALYST – aromatic sulfonic acid ester


Polyether + sulfonic ester cross-linked Polyether + sulfonic ester cross-linked rubberrubber

PROPERTIESPROPERTIES1.1. Working time is shortestWorking time is shortest

2.2. Permanent deformation is less than that of the Permanent deformation is less than that of the polysulfides but is not as low as that of the polysulfides but is not as low as that of the silicones.silicones.

3.3. Exhibits less flow under small loadsExhibits less flow under small loads

4.4. High stiffnessHigh stiffness

5.5. Dimensional change is lower than that of any Dimensional change is lower than that of any other rubber impression material except the other rubber impression material except the addition silicones. addition silicones.

6.6. Absorbs water and changes dimension if stored Absorbs water and changes dimension if stored in contact with water until equilibrium is in contact with water until equilibrium is reached.reached.

7.7. Viscosity of mixes can be reduced by using a Viscosity of mixes can be reduced by using a thinner. The thinner increases working time to 4 thinner. The thinner increases working time to 4 minutes and flexibility to 6%minutes and flexibility to 6%

8.8. Have a good shelf life and should be usable after Have a good shelf life and should be usable after 2 years of storage at room temperature.2 years of storage at room temperature.


1.1. Equal lengths are extruded onto a paper mixing Equal lengths are extruded onto a paper mixing pad. A uniform mix free of streaks should be pad. A uniform mix free of streaks should be obtained in 30 to 45 seconds.obtained in 30 to 45 seconds.

2.2. The use of a tray that follows for a thickness of The use of a tray that follows for a thickness of at least 4 mm of impression material helps in the at least 4 mm of impression material helps in the removal of the fairly stiff impression.removal of the fairly stiff impression.

3.3. The impression should be pulled slowly to break The impression should be pulled slowly to break the seal and then removed in a single stroke; it the seal and then removed in a single stroke; it should be rinsed with cold water, disinfected, should be rinsed with cold water, disinfected, and blown dry.and blown dry.

DISINFECTION OF RUBBER IMPRESSIONSDISINFECTION OF RUBBER IMPRESSIONSDisinfectants used:Disinfectants used:

1. Neutral glutaraldehyde1. Neutral glutaraldehyde2. Acidified glutaraldehyde2. Acidified glutaraldehyde3. Neutral phenolated glutaraldehyde3. Neutral phenolated glutaraldehyde4. Phenol4. Phenol5. Iodophor5. Iodophor6. Chlorine dioxide6. Chlorine dioxide

POLYSULFIDEPOLYSULFIDE

ADVANTAGESADVANTAGES– Good wettabilityGood wettability

– Good surface detailGood surface detail

– Easy to removeEasy to remove

– High tear strengthHigh tear strength

DISADVANTAGEDISADVANTAGE– High permanent High permanent

deformationdeformation

– Unpleasant taste & Unpleasant taste & odorodor

– Must pour within 1 hrMust pour within 1 hr

– Long setting timeLong setting time

– Take care when Take care when disinfectingdisinfecting

CONDENSATION SILICONECONDENSATION SILICONE

ADVANTAGESADVANTAGES– Good surface detailGood surface detail– Good dimensional Good dimensional

accuracyaccuracy– Low permanent Low permanent

deformationdeformation– Wide range of Wide range of

viscositiesviscosities– Easy to disinfectEasy to disinfect– Highly acceptable to Highly acceptable to

patientpatient

DISADVANTAGESDISADVANTAGES– HydrophobicHydrophobic

– Shrinks on storageShrinks on storage

– Must pour within 1 hrMust pour within 1 hr

– Low tear strengthLow tear strength

ADDITION SILICONEADDITION SILICONE

ADVANTAGESADVANTAGES– Good surface detailGood surface detail

– Good dimensional accuracyGood dimensional accuracy

– Good storage stabilityGood storage stability

– Low permanent Low permanent deformationdeformation

– Wide range of viscositiesWide range of viscosities

– Easy to disinfectEasy to disinfect

– Highly acceptable to patientHighly acceptable to patient

DISADVANTAGESDISADVANTAGES– Hydrophobic unless Hydrophobic unless

surfactant is addedsurfactant is added


POLYETHERPOLYETHER

ADVANTAGESADVANTAGES– HydrophilicHydrophilic

– Good surface detailGood surface detail

– Good dimensional Good dimensional accuracyaccuracy

– Good resistance to Good resistance to deformationdeformation

– Highly acceptable to Highly acceptable to patientpatient

DISADVANTAGESDISADVANTAGES– High permanent High permanent

deformationdeformation

– Swells in disinfectants Swells in disinfectants or moist environmentsor moist environments

– Difficult to removeDifficult to remove


– Take care when Take care when disinfectingdisinfecting

Elastomere Chemistry & compositionMain component

Setting reaction Packaging

I. Polysulfide multifunctional mercaptan or polysulfide polymerLead dioxide- gives a characteristic brown color

Mercaptan+

Lead dioxide↓

Polysulfide + H2Osensitive to moisture and temperature & hot and humid conditions accelerates the setting reaction

a. base paste - polysulfide polymer - filler (e.g. lithopone or titanium dioxide) to provide strength - plasticizer (e.g. dibutyl phthalate) to give viscosity - sulfur to accelerate reactionb. catalyst or accelerator paste (reactor) - lead dioxide - same plasticizer and filler - oleic or stearic acid as retarder to control rate of setting reaction

II. condensation-polymerizing silicone

Α-ω-hydroxyl-terminated polydimethyl siloxaneTri- or tetra-functional alkyl silicates ( tetraethyl orthosilicate and stannous octoate)

Dimethylsiloxane+

Ortho-ethyl silicate+

tin octoate↓

Silicone rubber +

ethyl alcohol(accounts for the contraction of set silicone elastomer)

a. base paste - putty (to overcome the large polymerization shrinkage)b. low-viscosity liquid catalyst (paste catalyst)



III. addition-polymerizing silicone (polyvinyl siloxane or vinyl polysiloxane)*hydrophobic - nonionic surfactants added to render it hydrophilic

vinyl siliconehydride silicone

Hydrogen-containing siloxane +

vinyl-terminal siloxane +

Chloroplatinic acid ↓

Silicone rubber(presence of impurities leads to development of hydrogen gas)-addition of platinum or palladium to prevent formation of pinpoint voids in the gypsum casts.-Wait an hour or more before pouring the impression

a. base paste - polymethyl hydrogen siloxane & other siloxane prepolymersb. catalyst paste - divinyl polydimethyl siloxane & other siloxane prepolymers(if the catalyst contains platinum salt activator then the base must contain the hybrid silicone)* latex gloves – inhibits setting



IV. Polyether Copolymer of ethylene oxide & tetrahydrofuran*initiator – aromatic sulfonate ester

Polyether +

Sulfonic ester ↓

Cross-linked rubber

a. base paste - polyether polymer - colloidal silica (filler) - glycolether or phthalate (plasticizer)b. accelerator paste - alkyl-aromatic sulfonate -filler -plasticizer

MAKING AN IMPRESSION:5 major steps:•preparing a tray•preparing the material•making an impression•removing the impression•preparing stone casts and dies

rubber impression material

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