Non-elastic Impression Material
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Transcript of 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
MANIPULATIONMANIPULATION
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
PROPERTIESPROPERTIES
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.
MANIPULATIONMANIPULATION
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.
`̀
PROPERTIESPROPERTIES
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