non-elastic impression material

Non-elastic impression Non-elastic impression

materialmaterial

dr.Manish dr.Manish kumarkumar

CONTENTSCONTENTS

DEFINITIONSDEFINITIONSCLASSIFICATIONCLASSIFICATION IMPRESSION PLASTERIMPRESSION PLASTER IMPRESSION COMPOUNDIMPRESSION COMPOUND IMPRESSION WAXESIMPRESSION WAXESZINC OXIDE EUGENOL IMPRESSION ZINC OXIDE EUGENOL IMPRESSION

PASTEPASTE

DEFINITIONDEFINITIONssImpression:Impression:

A negative likeness or copy in reverse of A negative likeness or copy in reverse of the surface of an object; (an imprint of the the surface of an object; (an imprint of the teeth and adjacent structures for use in teeth and adjacent structures for use in dentistry) dentistry) – GPT8– GPT8

Impression materialImpression material::

Any substance or combination of Any substance or combination of substances used for making an impression substances used for making an impression or negative reproduction or negative reproduction - GPT8- GPT8

CLASSIFICATION OF DENTAL IMPRESSION CLASSIFICATION OF DENTAL IMPRESSION MATERIALS BY SETTING MECHANISM AND BY MATERIALS BY SETTING MECHANISM AND BY

ELASTICITY AND USEELASTICITY AND USEBY SETTING BY SETTING

MECHANISMMECHANISM

BY ELASTICITY AND USEBY ELASTICITY AND USE

INELASTIC OR RIGIDINELASTIC OR RIGID ELASTICELASTIC

MATERIAL USE MATERIAL USE

*PLASTER OF

PARIS.*ZINC OXIDE

EUGENOL.

EDENTULOUS RIDGE.

*INTEROCCLUSAL RECORDS.

ALGINATE HYDROCOLLOID,NON-AQUEOUS ELASTOMERS,POLY SULFIDE,POLY ETHER,

CONDENSATION SILICONE,ADDITIONSILICONE.

CHEMICAL REACTION

(IRREVERSIBLE)

THERMALLY INDUCED

PHYSICAL REACTION.

(REVERSIBLE)

COMPOUND WAX.

PRELIMINARY IMPRESSION.

AGARHYDROCOLLOID.

TEETH AND

SOFT TISSUES.

TEETHAND

SOFT TISSUES.

IMPRESSION PLASTERIMPRESSION PLASTER

Impression plaster is similar in composition to Impression plaster is similar in composition to dental plaster used to construct models and dental plaster used to construct models and

dies.dies.

COMPOSITIONCOMPOSITION A calcined, A calcined, beta calcium sulphate hemihydrate beta calcium sulphate hemihydrate

Potassium sulphate:- Potassium sulphate:- anti expansion agentanti expansion agent accelerates setting reaction accelerates setting reaction Borax:- Borax:- a retardera retarder Alazarin red:- Alazarin red:- a pigment agenta pigment agent

Diatomacious earth, quartz, lime:- Diatomacious earth, quartz, lime:- to make the plaster more brittleto make the plaster more brittle

Soluble plasterSoluble plaster

Potato starch is added to impression Potato starch is added to impression plaster which acts as a separating media plaster which acts as a separating media while removing the impression from the while removing the impression from the cast.cast.

SETTING REACTIONSETTING REACTION

CaSOCaSO4 .4 .1/2H1/2H22o o CaSOCaSO44.2H.2H22O+HEAT+O+HEAT+

expansion app.0.1%expansion app.0.1%

WATER POWDER RATIOWATER POWDER RATIO

used at higher water powder ratio used at higher water powder ratio

0.40-0.750.40-0.75

SETTING TIMESETTING TIME

Lesser than other gypsum productsLesser than other gypsum products

4 minutes 4 minutes

IMPRESSION TRAYS USED FOR IMPRESSION TRAYS USED FOR IMPRESSION PLASTERIMPRESSION PLASTER

too fluid to be used in stock tray.too fluid to be used in stock tray.

Special trays are normally constructed Special trays are normally constructed using 1-1.5mm spacer. using 1-1.5mm spacer.

MANIPULATIONMANIPULATION

Dispensing of water and powderDispensing of water and powder

SpatulationSpatulation

Working time- 3 minutesWorking time- 3 minutes

FACTORS AFFECTING THE FACTORS AFFECTING THE SETTING REACTIONSETTING REACTION

Manipulation Manipulation VariablesVariables

Setting Setting

timetime

Consist- Consist- encyency

SettingSetting

ExpansionExpansion

Compre-Compre-ssivessive

strengthstrength

Increased Increased W/P ratioW/P ratio

Increased Increased rate of rate of spatulationspatulation

Increased Increased water temp.water temp.

no changeno changedecreaseddecreasedincreasedincreased

IMPRESSION TECHNIQUEIMPRESSION TECHNIQUE

The technique for insertion of impression into The technique for insertion of impression into the mouth involves “puddling” the impression the mouth involves “puddling” the impression into place into place

The tray containing impression plaster is The tray containing impression plaster is seated in patient’s mouth and then gently seated in patient’s mouth and then gently move from side to side and antero-move from side to side and antero-posteriorly, this allow the material to flow in posteriorly, this allow the material to flow in every area of the mouth every area of the mouth

Primary Impression with impression Primary Impression with impression plasterplaster

DISINFECTIONDISINFECTION

Sodium hypochlorite in 1:10 dilutionSodium hypochlorite in 1:10 dilution2% alkaline gluteraldehyde solution2% alkaline gluteraldehyde solution IodophoresIodophoresPhenolic sprayPhenolic spray

PROPERTIES OF IMPRESSION PROPERTIES OF IMPRESSION PLASTERPLASTER

Regarding properties the difference between Regarding properties the difference between impression plaster and model plaster isimpression plaster and model plaster is ::

1 They have more rapid setting in order to avoid 1 They have more rapid setting in order to avoid inconvenience.inconvenience.

2 Have smaller setting expansion for greater 2 Have smaller setting expansion for greater accuracy.accuracy.

3.3. Much lower strength ; fractures easily if the Much lower strength ; fractures easily if the material engages an undercut.material engages an undercut.

4.4. Colouring agent for contrastColouring agent for contrast

USESUSES

Recording impression of patient with Recording impression of patient with excessively mobile soft tissues overlying excessively mobile soft tissues overlying the residual alveolar bone.the residual alveolar bone.

Wash impressionWash impression

DISADVANTAGEDISADVANTAGE

VERY RIGIDVERY RIGIDMAY DRY SOFT TISSUESMAY DRY SOFT TISSUESFRACTURES IF UNDERCUT PRESENTFRACTURES IF UNDERCUT PRESENT

OLD FASHION – OLD FASHION – NOT FREQUENTLY USEDNOT FREQUENTLY USED

IMPRESSION COMPOUNDIMPRESSION COMPOUND

Impression compound is a thermoplastic Impression compound is a thermoplastic material having the properties similar to material having the properties similar to

dental waxes.dental waxes.

TYPES OF IMPRESSION TYPES OF IMPRESSION COMPOUNDCOMPOUND

TYPE I (LOWER FUSING):TYPE I (LOWER FUSING): Used for Used for taking impression.taking impression.

TYPE II(HIGHER FUSING): TYPE II(HIGHER FUSING): Used for Used for construction of impression trays.construction of impression trays.

MODES OF DISPENSIONMODES OF DISPENSION

Type I materials are supplied either in sheet Type I materials are supplied either in sheet or stick form. or stick form.

Sheet form is used for recording impression of Sheet form is used for recording impression of edentulous ridges.edentulous ridges.

Stick form is used for border extension on Stick form is used for border extension on impression tray or for recording impression of impression tray or for recording impression of single crown using copper ring technique.single crown using copper ring technique.

CompositionComposition

Ingredient Ingredient parts in %parts in % RosinRosin 3030 Copal resinCopal resin 3030 Carnauba waxCarnauba wax 1010 Stearic acidStearic acid 55 TalcTalc 2525 Colouring agentColouring agent Appropriate amountAppropriate amount


The sheet material is normally softened using a The sheet material is normally softened using a water bath.water bath.

Softening temperature range 55-60’C Softening temperature range 55-60’C It should not be so long and it should not be too It should not be so long and it should not be too

short short If the conditioning temperature is too low the If the conditioning temperature is too low the

material does not soften properly and if too material does not soften properly and if too high, it becomes sticking and unmanageablehigh, it becomes sticking and unmanageable

The stick material is generally softened The stick material is generally softened using a flame.using a flame.

The material is then tempered in water The material is then tempered in water bath before placing in patient’s mouth.bath before placing in patient’s mouth.

PROPERTIESPROPERTIES

fairly rigid after setting and is non-elastic fairly rigid after setting and is non-elastic in nature. in nature.

high viscosity.high viscosity. a mucocompressive impression materiala mucocompressive impression material poor thermal conductivity.poor thermal conductivity. The material have large values of The material have large values of

coefficient of thermal expansion and coefficient of thermal expansion and undergo considerable shrinkage on undergo considerable shrinkage on removal from the mouth.removal from the mouth.

Fusion temperature-indicates definite Fusion temperature-indicates definite reduction in the plasticity during coolingreduction in the plasticity during cooling

43.5’C.43.5’C.Glass transition temperature-is the Glass transition temperature-is the

temperature at which material forms a rigid temperature at which material forms a rigid massmass

39’C.39’C.

Permissible flow values for dental compounds Permissible flow values for dental compounds as defined by ANSI/ADA specification No.3as defined by ANSI/ADA specification No.3

MATERIAL MATERIAL Flow Flow

AT 37oC at 45oCAT 37oC at 45oC

Type I less than 6%Type I less than 6% more more than85%than85%

(impression compound) (impression compound)

Type II less than 2% 70%-85%.Type II less than 2% 70%-85%.

(trey compound)(trey compound)

USESUSES

for making edentulous impression for making edentulous impression

border extension on impression traysborder extension on impression trays

recording impression of single crown recording impression of single crown using using copper ringcopper ring technique technique

to check undercut in inlay preparationto check undercut in inlay preparation Stabilizes the matrix band. Stabilizes the matrix band.

ADVANTAGESADVANTAGES

Can be reusedCan be reusedEasy to useEasy to useNon irritantNon irritantNon toxicNon toxicCheaperCheaper

DISADVANTAGESDISADVANTAGES

Difficult to record detailsDifficult to record detailsPoor dimensional stabilityPoor dimensional stabilityEasy to distort when withdrawn from the Easy to distort when withdrawn from the

mouthmouthNo fine details are obtainedNo fine details are obtained

Impression waxesImpression waxes

Also used the term Also used the term corrective impression corrective impression waxwax

A A thermoplasticthermoplastic impression material impression material

COMPOSITIONCOMPOSITION

No ADA specification for impression waxNo ADA specification for impression wax

Paraffin waxParaffin wax

Bees waxBees wax

CeresinCeresin

Metal particlesMetal particles

MANIPULATION MANIPULATION

MeltedMeltedApplied to defectApplied to defectReseated under firm finger pressureReseated under firm finger pressureAllow the wax to setAllow the wax to set

OTHER USESOTHER USES

Wax veneer Wax veneer Mucocompressive impression-Applegate Mucocompressive impression-Applegate

techniquetechnique


Thermoplastic materialThermoplastic materialRelatively soft at room temperatureRelatively soft at room temperatureFlow is measured by penetration at 37 c is Flow is measured by penetration at 37 c is

100%100%

Zinc oxide /eugenol impression Zinc oxide /eugenol impression pastespastes

Zinc oxide Eugenol is a non-elastic Zinc oxide Eugenol is a non-elastic impression materialimpression material..

TYPESTYPES

According to According to ADA specification no.16ADA specification no.16 ; ; based on based on consistency and hardnessconsistency and hardness,,

Type I - hard(10mins)Type I - hard(10mins)

Type II - soft(15mins)Type II - soft(15mins)

CHEMICAL COMPOSITIONCHEMICAL COMPOSITION Material is normally supplied as two paste which are mixed Material is normally supplied as two paste which are mixed

together on a paper pad or glass.together on a paper pad or glass.

COMPONENTCOMPONENT FUNCTIONFUNCTION

PASTE IPASTE I Zinc oxide Zinc oxide Reactive ingredient which Reactive ingredient which take part in setting reactiontake part in setting reaction

Olive oil, linseed oil or equivalentOlive oil, linseed oil or equivalent Inert component used to form Inert component used to form paste with zinc oxidepaste with zinc oxide

Zinc acetate or equivalentZinc acetate or equivalent To accelerate settingTo accelerate setting

Water (trace) in some products Water (trace) in some products To accelerate settingTo accelerate setting

PASTE PASTE IIII

Eugenol (oil of cloves) Eugenol (oil of cloves) Reactive ingredient take part Reactive ingredient take part in setting reactionin setting reaction

caolin, talc or equivalentcaolin, talc or equivalent Inert filler used to form a paste Inert filler used to form a paste with eugenolwith eugenol

SETTING REACTIONSETTING REACTION

The formation of chelate compound.The setting reaction is ionic in natureSome manufacturers incorporates water as

the component of at least one of the paste.

FACTORS AFFECTING THE FACTORS AFFECTING THE SETTING REACTIONSETTING REACTION

Under control of Under control of

ManufacturerManufacturer

Under control ofUnder control of

OperatorOperator

Accelerators like-Accelerators like-

calcium chloridecalcium chloride

zinc acetatezinc acetate

waterwater

To shorten the setting timeTo shorten the setting time

1-Accelerators like-drop of H2O1-Accelerators like-drop of H2O

2- extending mixing time2- extending mixing time

To prolong the setting timeTo prolong the setting time

1-cool spatula and glass slab1-cool spatula and glass slab

2-plastisizer like-inert oil, wax or 2-plastisizer like-inert oil, wax or petroleum gel petroleum gel

MODE OF DISPENSIONMODE OF DISPENSION The pastes are normally dispensed from tooth The pastes are normally dispensed from tooth

paste like tubes and mixed in equal volume.paste like tubes and mixed in equal volume.

One tube is labeled as catalyst and one is One tube is labeled as catalyst and one is labeled as base paste.labeled as base paste.


The proportioning is achieved simply by The proportioning is achieved simply by expression of equal length of each paste expression of equal length of each paste on to the mixing pad or slab on to the mixing pad or slab

There is a good color contrast between the There is a good color contrast between the pastes which aid in homogenous, streak pastes which aid in homogenous, streak free mixing.free mixing.


Zinc oxide eugenol is low viscosity, non-elastic Zinc oxide eugenol is low viscosity, non-elastic impression material.impression material.

Because of the lack of elasticity the set material Because of the lack of elasticity the set material may fracture when removed over undercut.may fracture when removed over undercut.

Some patients are allergic to eugenol so in that Some patients are allergic to eugenol so in that case eugenol free pastes are available. The case eugenol free pastes are available. The eugenol is replaced by alternative organic acid.eugenol is replaced by alternative organic acid.

The material can be added to the impression The material can be added to the impression once the material is set so that any correction in once the material is set so that any correction in impression can be made with this material.impression can be made with this material.

USESUSES

AN IMPRESSION MATERIALS FOR AN IMPRESSION MATERIALS FOR EDENTULOUS MOUTHSEDENTULOUS MOUTHS

SURGICAL DRESSINGSURGICAL DRESSING

TEMPORARY FILLING MATERIALTEMPORARY FILLING MATERIAL

ROOT CANAL FILLINGROOT CANAL FILLING

BITE REGISTRATION BITE REGISTRATION

TEMPORARY RELINING MATERIALS FOR TEMPORARY RELINING MATERIALS FOR DENTURESDENTURES

non-elastic impression material

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