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IMPRESSIONIMPRESSION
MATERIALSMATERIALS
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacadem...
INTRODUCTIONINTRODUCTION
Constructing a model or cast is anConstructing a model or cast is an
important step in numerous d...
HISTORYHISTORY
 1558 -Celline described a wax model to make impression in his1558 -Celline described a wax model to make ...
HISTORYHISTORY
 1930 – Znic Oxide Eugenol a ridged impression was introduced1930 – Znic Oxide Eugenol a ridged impression...
Based on the mode of
setting and elasticity
Rigidity
material
Elastic
material
Reversible Irreversible Hydrocolloid
Elasto...
BASED ON MANIPULATION
HAND MIXING
MACHANICAL
MIXING
KNEADING
CIRCULAR
MOTION
VIGOROUS
MIXING
IMPRESSION
COMPOUND POLYSULFI...
BASED ON THE TYPE OF
IMPRESION & AREA OF USED
DENTULOUS
ALGINATE
EDENTULOUS
PRIMARY SECONDARY PRIMARY
SECONDARY
AGAR
ELAST...
BASED ON THE TRAY USED
FOR IMPRESSION
SPECIAL
TRAY
STOCK
TRAY
TYPES OF
TRAY
BASED ON
PERFORATION
RIM
LOCKED
PERFORATED
WAT...
IDEAL REQUIREMENTS OFIDEAL REQUIREMENTS OF
IMPRESSION MATERIALIMPRESSION MATERIAL
1. Pleasant taste & odor1. Pleasant tast...
HYDROCOLLOIDSHYDROCOLLOIDS
 Colloids are often classified as fourth state of matter, the ColloidalColloids are often clas...
GelsGels
 Colloids with a liquid as the dispersion medium can existColloids with a liquid as the dispersion medium can ex...
Gelation may be brought about in one of these wayGelation may be brought about in one of these way
 Lowering the temperat...
Type of HydrocolloidsType of Hydrocolloids
 sol can be changed to gel, but gel cant besol can be changed to gel, but gel ...
ALGINATE IRREVERSIBLEALGINATE IRREVERSIBLE
HYDROCOLOOIDHYDROCOLOOID
 The word alginate comes from Algin & named by aThe w...
compositioncomposition
1.1. Potassium or Sodium AlginatePotassium or Sodium Alginate :- 15%:- 15%
It is the chief active i...
Gelation ProcessGelation Process
 The typical sol-gel reaction is a soluble alginate with calcium sulfate & theThe typica...
PROPERTIESPROPERTIES
 Alginate is of two typeAlginate is of two type
1.1. Type I :- Fast settingType I :- Fast setting
2....
PROPERTIESPROPERTIES
4.4. Permanent deformationPermanent deformation :- ADA:- ADA
specification requires 97% recovery & wh...
PROPERTIESPROPERTIES
9.9. Dimensional effectsDimensional effects :- -The gel may loss:- -The gel may loss
water by evapora...
MANIPULATION OF ALGINATEMANIPULATION OF ALGINATE PREPARING THE MIXPREPARING THE MIX
A measured powder is shifted into pre...
MODIFIED ALGINATEMODIFIED ALGINATE
 Alginate modified by the incorporation of Silicone. These areAlginate modified by the...
AGAR – REVERSIBLEAGAR – REVERSIBLE
HYDROCOLLOIDSHYDROCOLLOIDS
 When agar hydrocolloids heated, they liquefyWhen agar hydr...
COMPOSITIONCOMPOSITION
1.1. BoratesBorates :- 0.2 – 0.5%:- 0.2 – 0.5%
Its works as retader.Its works as retader.
2.2. wate...
GELATION PROCESSGELATION PROCESS
 The setting of the reversible hydrocolloid is called gelation. TheThe setting of the re...
PROPERTIESPROPERTIES
 Gelation temperatureGelation temperature :-:-
After tempering the sol should be homogenous and shou...
PROPERTIESPROPERTIES
 FlexibilityFlexibility :-:-
The ADA specification requirement for flexibility allows a rangeThe ADA...
Manipulation of agar impression:Manipulation of agar impression:
The use of agar hydrocolloid involveThe use of agar hydro...
Impression tray:Impression tray:
It is rim locked trays with water circulatingIt is rim locked trays with water circulatin...
Preparation of material:Preparation of material:
Proper equipment of liquefying andProper equipment of liquefying and
stor...
Conditioning and tempering:Conditioning and tempering:
Because 55 degree is the maximum tolerableBecause 55 degree is the ...
Making the impression:Making the impression:
The syringe material is taken directly from theThe syringe material is taken ...
Disinfection hydrocolloidDisinfection hydrocolloid
impression:impression:
.. As the hydrocolloid impression material must ...
ADVANTAGES & DISADVANTAGEADVANTAGES & DISADVANTAGE
ImpressionImpression
materialsmaterials
Brand nameBrand name Advantages...
TYPES OF FALIURESTYPES OF FALIURES
1.1.DistortionDistortion :- due to:- due to
 Delayed pouring of impressionDelayed pour...
INELASTIC OR RIGIEDINELASTIC OR RIGIED
IMPRESSION MATERIALIMPRESSION MATERIAL
In elastic impression materials exhibit anIn...
Impression compoundImpression compound
 Impression compound is aImpression compound is a
thermoplastic material. When its...
REQUIREMENT OF IDEALREQUIREMENT OF IDEAL
IMPRESSION COMPOUNDIMPRESSION COMPOUND
1.1. Solidified or harden at or little abo...
COPOSITIONCOPOSITION
1.1. Thermoplastic materialThermoplastic material:- 50%:- 50%
Natural or synthetic resins & waxes are...
PROPERTIESPROPERTIES
1.1. Thermal propertiesThermal properties :-:-
It is very low. The coefficient of contraction of impr...
DISINFECTIONDISINFECTION
 The recommended disinfectant solution for compound is 2% alkalineThe recommended disinfectant s...
ZINC OXIED EUGENOL IMPRESSIONZINC OXIED EUGENOL IMPRESSION
PASTEPASTE
 Under proper condition, the reaction betweenUnder ...
COPOSITIONCOPOSITION
Usually its come in two tube in paste formUsually its come in two tube in paste form
 Base pasteBase...
MANIPULATIONMANIPULATION
 The mixing of two paste isThe mixing of two paste is
generally accomplished on angenerally acco...
PROPERTIESPROPERTIES
1.1. Setting timeSetting time:-:-
Once the material in a plastic condition is carried to the mouth, o...
DISINFECTIONDISINFECTION
The recommended disinfectant solution forThe recommended disinfectant solution for
ZOE impression...
NON EUGENOL PASTENON EUGENOL PASTE
One of the chief disadvantage of ZOE paste isOne of the chief disadvantage of ZOE paste...
BITE REGISTRATION PASTEBITE REGISTRATION PASTE
The materials used for recording theThe materials used for recording the
oc...
ELASTOMERIC IMPRESSIONELASTOMERIC IMPRESSION
MATERIALMATERIAL
 Elastomers refer to a group of rubbery polymers, which are...
Properties of ElastomericProperties of Elastomeric
Impression MaterialImpression Material
1.1. Excellent reproduction abil...
POLYSULFIED IMPRESSIONPOLYSULFIED IMPRESSION
 This was the first elastomeric impressionThis was the first elastomeric imp...
COMPOSITIONCOMPOSITION
 BASE PASTEBASE PASTE
1.1. Liquid polysulfide polymerLiquid polysulfide polymer:-80:-80
-85%-85%
2...
CHEMISTRYCHEMISTRY
 The main component of polysulfide material is aThe main component of polysulfide material is a
multif...
PROPERTIESPROPERTIES
1.1. Setting timeSetting time:-:-
16 min at 23 degree16 min at 23 degree
12.5 min at 37 degree12.5 mi...
PROPERTIESPROPERTIES
6.6. Tear strengthTear strength :-:-
it is high. It is 2500 – 7000M/nit is high. It is 2500 – 7000M/n...
SILICONE RUBBER IMPRESIONSILICONE RUBBER IMPRESION
MATERIALMATERIAL
 These materials were developed to overThese material...
CONDENSATION SILICONECONDENSATION SILICONE
 This was the earlier of the two silicone impressionThis was the earlier of th...
COMPOSITIONCOMPOSITION
 BASEBASE
1.1. Hydroxyl terminated polydimethylHydroxyl terminated polydimethyl
siloxanesiloxane :...
CHEMISTRYCHEMISTRY
 It is a condensation reaction. PolymerizationIt is a condensation reaction. Polymerization
occurs as ...
PROPERTIESPROPERTIES
1.1. Working timeWorking time:-:-
it is 3.3 min at 23 degreeit is 3.3 min at 23 degree
it is 2.5 min ...
PROPERTIESPROPERTIES
6.6. Tear strengthTear strength :-:-
2300 – 2600N/m2300 – 2600N/m
7. More stiffer & harder than the p...
ADDITIONADDITION SILICONESILICONE
 It has a better propertiesIt has a better properties
than condensation silicones.than ...
COMPOSITIONCOMPOSITION
 BASEBASE
1.1. Poly methyl hydrogen siloxanePoly methyl hydrogen siloxane
2.2. Other siloxane prep...
CHEMIETRYCHEMIETRY
 It is an addition reaction. In this case theIt is an addition reaction. In this case the
base polymer...
PROPERTIESPROPERTIES
1.1. Working timeWorking time :-:-
it is 3.1 min at 23degreeit is 3.1 min at 23degree
it is 1.8min at...
PROPERTIESPROPERTIES
6. Hydrophobic6. Hydrophobic
7. Low flexibility & is harder than polysulfide.7. Low flexibility & is ...
POLYETHER IMPRESSIONPOLYETHER IMPRESSION
MATERIALMATERIAL
 This was introduced in Germany in late 1960’s. it hasThis was ...
COMPOSITIONCOMPOSITION

BASEBASE
1.1. Polyether polymerPolyether polymer :-:-
2.2. Inert fillerInert filler :-:-
Colloida...
CHEMISTRYCHEMISTRY
 It is cured by the reaction between aziridineIt is cured by the reaction between aziridine
rings whic...
PROPERTIESPROPERTIES
1.1. Working timeWorking time :-:-
it is 3.3 min at 23 degreeit is 3.3 min at 23 degree
it is 2.3 min...
PROPERTIESPROPERTIES
6.6. Tear strengthTear strength :-:-
1800 – 4800N/m1800 – 4800N/m
7. Hydrophilic7. Hydrophilic
8.8. B...
LIGHT ACTIVATED IMPRESSIONLIGHT ACTIVATED IMPRESSION
MATERIALMATERIAL
 With the increase used of light activated restorat...
COMPOSITIONCOMPOSITION
1.1. Polyether urethanePolyether urethane
dimethacrylatedimethacrylate
2.2. Photo initiatorPhoto in...
PROPERTIESPROPERTIES
1.1. This material have a very long workingThis material have a very long working
time but short sett...
MANIPULATION OFMANIPULATION OF
ELASTOMERIC MATERIALELASTOMERIC MATERIAL
 SPATULATIONSPATULATION :-:-
Impression materials...
DISINFECTION OFDISINFECTION OF
ELASTOMERIC MATERIALSELASTOMERIC MATERIALS
1.1. POLYSULFIED IMPRESSION MATERIALPOLYSULFIED ...
COMMON FAILURE THET OCCUR WITH USECOMMON FAILURE THET OCCUR WITH USE
OF ELASTOMERIC IMPRESSION MATERIALOF ELASTOMERIC IMPR...
ADVANTAGES & DISADVANTAGESADVANTAGES & DISADVANTAGES
MATERIALSMATERIALS ADVANTAGESADVANTAGES DISADVANTAGESDISADVANTAGES
1....
ADVATAGES & DISADVANTAGESADVATAGES & DISADVANTAGES
MATERIALSMATERIALS ADVANTAGESADVANTAGES DISADVANTAGESDISADVANTAGES
Addi...
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Dental Impression material / dental implant courses by Indian dental academy  Slide 3 Dental Impression material / dental implant courses by Indian dental academy  Slide 4 Dental Impression material / dental implant courses by Indian dental academy  Slide 5 Dental Impression material / dental implant courses by Indian dental academy  Slide 6 Dental Impression material / dental implant courses by Indian dental academy  Slide 7 Dental Impression material / dental implant courses by Indian dental academy  Slide 8 Dental Impression material / dental implant courses by Indian dental academy  Slide 9 Dental Impression material / dental implant courses by Indian dental academy  Slide 10 Dental Impression material / dental implant courses by Indian dental academy  Slide 11 Dental Impression material / dental implant courses by Indian dental academy  Slide 12 Dental Impression material / dental implant courses by Indian dental academy  Slide 13 Dental Impression material / dental implant 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Dental Impression material / dental implant courses by Indian dental academy 

  1. 1. IMPRESSIONIMPRESSION MATERIALSMATERIALS INDIAN DENTAL ACADEMY Leader in continuing Dental Education www.indiandentalacademy.comwww.indiandentalacademy.com
  2. 2. INTRODUCTIONINTRODUCTION Constructing a model or cast is anConstructing a model or cast is an important step in numerous dentalimportant step in numerous dental procedure. Various types of cast & modelsprocedure. Various types of cast & models can be made from gypsum products usingcan be made from gypsum products using an impression mold or negative likenessan impression mold or negative likeness of a dental structure. A impression is aof a dental structure. A impression is a negative replica of the tissue of the oralnegative replica of the tissue of the oral cavity. It is used to register or reproducecavity. It is used to register or reproduce the form and relation of the teeth &the form and relation of the teeth & surrounding tissue.surrounding tissue. www.indiandentalacademy.comwww.indiandentalacademy.com
  3. 3. HISTORYHISTORY  1558 -Celline described a wax model to make impression in his1558 -Celline described a wax model to make impression in his book MEMORIES.book MEMORIES.  1700 - Mathaeus G. Purenam suggested that wax models can1700 - Mathaeus G. Purenam suggested that wax models can be used in prosthetic work.be used in prosthetic work.  1728 – Pieere Fauchord described various impression material1728 – Pieere Fauchord described various impression material in his book LE CHIRURGEEN DENTISTE.in his book LE CHIRURGEEN DENTISTE.  1756 – Persian Phillip Pfaff first use plaster models prepared1756 – Persian Phillip Pfaff first use plaster models prepared from sectional wax impression of the mouth.from sectional wax impression of the mouth.  1810 – R C Skinner describe about many materials and1810 – R C Skinner describe about many materials and techniques in his first American book.techniques in his first American book.  1928 – ADA developed specification No. 19 for impression1928 – ADA developed specification No. 19 for impression materialmaterial www.indiandentalacademy.comwww.indiandentalacademy.com
  4. 4. HISTORYHISTORY  1930 – Znic Oxide Eugenol a ridged impression was introduced1930 – Znic Oxide Eugenol a ridged impression was introduced  1930 – Polysulfide was first used as a commercial synthetic1930 – Polysulfide was first used as a commercial synthetic rubber as a copolymer of Ethylene Chloride & sodium.rubber as a copolymer of Ethylene Chloride & sodium.  1937 – Agar was introduced by Sears.1937 – Agar was introduced by Sears.  1949 – Alginate was developed during World war II.1949 – Alginate was developed during World war II.  1950 – Polysulfide was used in dentistry.1950 – Polysulfide was used in dentistry.  1955 – Condensation Silicone was introduced in Germany.1955 – Condensation Silicone was introduced in Germany.  1975 – Addition Silicone was introduced.1975 – Addition Silicone was introduced.  1977 – Costell introduced Dual tray technique.1977 – Costell introduced Dual tray technique.  1980 – A Visible light cure Polyether Urethane Dimethacrylate1980 – A Visible light cure Polyether Urethane Dimethacrylate rubber impression material was introduced.rubber impression material was introduced.  1996 – Blare & Wassed Considered a no. of solution used to1996 – Blare & Wassed Considered a no. of solution used to disinfecting impression material.disinfecting impression material. www.indiandentalacademy.comwww.indiandentalacademy.com
  5. 5. Based on the mode of setting and elasticity Rigidity material Elastic material Reversible Irreversible Hydrocolloid Elastomeric Impression Material Impression compound Impression Plaster ZOE Impression Material Irreversible Reversible Condensation silicone Addition silicones Polyether Polysulfide www.indiandentalacademy.comwww.indiandentalacademy.com
  6. 6. BASED ON MANIPULATION HAND MIXING MACHANICAL MIXING KNEADING CIRCULAR MOTION VIGOROUS MIXING IMPRESSION COMPOUND POLYSULFIDES ZOE IMPRESSION MATERIAL ALGINATE www.indiandentalacademy.comwww.indiandentalacademy.com
  7. 7. BASED ON THE TYPE OF IMPRESION & AREA OF USED DENTULOUS ALGINATE EDENTULOUS PRIMARY SECONDARY PRIMARY SECONDARY AGAR ELASTOMERS ALGINATE IMPRESSION PLASTER IMPRESSION COMPOUND ZOE IMPRESSION MATERIAL ELASTOMERS www.indiandentalacademy.comwww.indiandentalacademy.com
  8. 8. BASED ON THE TRAY USED FOR IMPRESSION SPECIAL TRAY STOCK TRAY TYPES OF TRAY BASED ON PERFORATION RIM LOCKED PERFORATED WATER COOLED TRAY PLASTIC TRAY PERFORATED NON PERFORATED BASED PLATE RESIN PLATE ALGINATE AGAR-AGAR ELASTOMER IIMPRESSION COMPOUNDPUTTY WASH IMPRESSION ZOE IMPRESSION MATERIAL www.indiandentalacademy.comwww.indiandentalacademy.com
  9. 9. IDEAL REQUIREMENTS OFIDEAL REQUIREMENTS OF IMPRESSION MATERIALIMPRESSION MATERIAL 1. Pleasant taste & odor1. Pleasant taste & odor 2. Not contain any toxic & irritating ingredients2. Not contain any toxic & irritating ingredients 3. Adequate shelf life3. Adequate shelf life 4.Satisfactory consistency and texture4.Satisfactory consistency and texture 5.Easy to disinfect with out loss of accuracy5.Easy to disinfect with out loss of accuracy 6.Compatible with die and cast material6.Compatible with die and cast material 7.Dimentional stability7.Dimentional stability 8.Good elastic properties8.Good elastic properties 9.Easy manipulation9.Easy manipulation 10.Adequate setting characteristics10.Adequate setting characteristics 11.High degree of reproduction details11.High degree of reproduction details 12.Adequate strength12.Adequate strength 13.Should not release any gas13.Should not release any gas 14.Economical14.Economical 15.Should not be technique sensitive15.Should not be technique sensitive www.indiandentalacademy.comwww.indiandentalacademy.com
  10. 10. HYDROCOLLOIDSHYDROCOLLOIDS  Colloids are often classified as fourth state of matter, the ColloidalColloids are often classified as fourth state of matter, the Colloidal state. In a solution of sugar in water, the sugar molecules arestate. In a solution of sugar in water, the sugar molecules are uniformly dispersed in the water & there is no visible physicaluniformly dispersed in the water & there is no visible physical separation between the solute & the solvent molecules. If sugarseparation between the solute & the solvent molecules. If sugar molecules replaced with large & visible particles such as sand, themolecules replaced with large & visible particles such as sand, the system is Suspension or if molecules are liquid such vegetable oil,system is Suspension or if molecules are liquid such vegetable oil, then system is Emulsion.then system is Emulsion.  True solution exist as a single phase. However, both the colloid &True solution exist as a single phase. However, both the colloid & the suspension have to phase- The dispersed & Dispersion phase.the suspension have to phase- The dispersed & Dispersion phase. In the colloid , the particles in the dispersed phase consist ofIn the colloid , the particles in the dispersed phase consist of molecules held together either by primary or secondary force. Themolecules held together either by primary or secondary force. The size of the particles range is 1 – 200nmsize of the particles range is 1 – 200nm www.indiandentalacademy.comwww.indiandentalacademy.com
  11. 11. GelsGels  Colloids with a liquid as the dispersion medium can existColloids with a liquid as the dispersion medium can exist in two different forms known as Sol & Gel.in two different forms known as Sol & Gel.  A sol has the appearance & many characteristic of aA sol has the appearance & many characteristic of a various liquid.various liquid.  A gel, on the contrary, is a semi solid & produced from aA gel, on the contrary, is a semi solid & produced from a soldering process of gelation by the formation of fibrilssoldering process of gelation by the formation of fibrils or chains called Micelles.or chains called Micelles.  Gelation is the conversion of a sol to gel, & theGelation is the conversion of a sol to gel, & the temperature at which this occurs is calledtemperature at which this occurs is called Gelation Temperature.Gelation Temperature. www.indiandentalacademy.comwww.indiandentalacademy.com
  12. 12. Gelation may be brought about in one of these wayGelation may be brought about in one of these way  Lowering the temperature :-Lowering the temperature :- It is done by reducing the thermalIt is done by reducing the thermal energy of molecules, allows inter molecular forces of attractionenergy of molecules, allows inter molecular forces of attraction to operate more effectively. These forces are secondaryto operate more effectively. These forces are secondary molecular forces. The bond between the fibrils are weak & theymolecular forces. The bond between the fibrils are weak & they break at slightly elevated temperature. Gelation temp. is 37-break at slightly elevated temperature. Gelation temp. is 37- 50degree centigrade.50degree centigrade.  Liquefaction temperatureLiquefaction temperature :- It is considerable higher than:- It is considerable higher than gelation tamp. & this properties is known as Hytersis. Thisgelation tamp. & this properties is known as Hytersis. This temp. is between 70 -100 degree centigrade.temp. is between 70 -100 degree centigrade.  Chemical reactionChemical reaction :- Gelation may also induced by chemical:- Gelation may also induced by chemical reaction, where in the dispersed phase of soil is allowed toreaction, where in the dispersed phase of soil is allowed to react with a substance to give a different type of dispersedreact with a substance to give a different type of dispersed phase. The process is not reversed by an increasedphase. The process is not reversed by an increased temperature.temperature. www.indiandentalacademy.comwww.indiandentalacademy.com
  13. 13. Type of HydrocolloidsType of Hydrocolloids  sol can be changed to gel, but gel cant besol can be changed to gel, but gel cant be reversed back to the solution. Eg. Alginatereversed back to the solution. Eg. Alginate impression materialimpression material  REVERSIBLE HYDROCOLLOIDS :-REVERSIBLE HYDROCOLLOIDS :- Reversible hydrocolloids are thoseReversible hydrocolloids are those IRREVERSIBLE HYDROCOLLOIDS :-IRREVERSIBLE HYDROCOLLOIDS :- Irreversible hydrocolloids are those materialsIrreversible hydrocolloids are those materials where the materials, where the change fromwhere the materials, where the change from the sol to gel can be brought by lowering thethe sol to gel can be brought by lowering the temp. of the sol & the gel can be convertedtemp. of the sol & the gel can be converted back to sol condition by heating. Eg. Agar –back to sol condition by heating. Eg. Agar – Agar.Agar. www.indiandentalacademy.comwww.indiandentalacademy.com
  14. 14. ALGINATE IRREVERSIBLEALGINATE IRREVERSIBLE HYDROCOLOOIDHYDROCOLOOID  The word alginate comes from Algin & named by aThe word alginate comes from Algin & named by a chemist of Scotland. It was identified as a linerchemist of Scotland. It was identified as a liner polymer with numerous carboxyl acid group. It ispolymer with numerous carboxyl acid group. It is called as irreversible hydrocolloids becausecalled as irreversible hydrocolloids because gelation is induced by chemical reaction &gelation is induced by chemical reaction & transformation is not possible. It is the most widelytransformation is not possible. It is the most widely used dental materials. The principal factorsused dental materials. The principal factors responsible for the success of this type ofresponsible for the success of this type of impression materials are:-impression materials are:- 1.1. Easy to manipulateEasy to manipulate 2.2. Comfortable for the patients.Comfortable for the patients. 3.3. Relatively inexpensive.Relatively inexpensive. www.indiandentalacademy.comwww.indiandentalacademy.com
  15. 15. compositioncomposition 1.1. Potassium or Sodium AlginatePotassium or Sodium Alginate :- 15%:- 15% It is the chief active ingredientIt is the chief active ingredient 2.2. Calcium Sulfate :-Calcium Sulfate :- 16%16% It is used as a reactor.It is used as a reactor. 3.3. Zinc Oxide & Diatomaccous EarthZinc Oxide & Diatomaccous Earth:-:- Zinc oxide – 4% &Zinc oxide – 4% & Diatomaccous earth – 60%Diatomaccous earth – 60% 4.4. Potassium Titanium FluoridePotassium Titanium Fluoride :- 3%:- 3% 5.5. Sodium PhosphateSodium Phosphate :- 2%:- 2% www.indiandentalacademy.comwww.indiandentalacademy.com
  16. 16. Gelation ProcessGelation Process  The typical sol-gel reaction is a soluble alginate with calcium sulfate & theThe typical sol-gel reaction is a soluble alginate with calcium sulfate & the formation of an insoluble calcium alginate gel. Calcium sulfate reacts rapidlyformation of an insoluble calcium alginate gel. Calcium sulfate reacts rapidly to produced the in soluble Ca alginate from the potassium or sodiumto produced the in soluble Ca alginate from the potassium or sodium alginate in a aqueous solution. The production of calcium alginate is rapidalginate in a aqueous solution. The production of calcium alginate is rapid that it does not allow sufficient working time. Thus third water soluble salt,that it does not allow sufficient working time. Thus third water soluble salt, such as a trisodium phosphate, is added to the solution to prolong thesuch as a trisodium phosphate, is added to the solution to prolong the working time. Thus the reaction between the calcium sulfate & the solubleworking time. Thus the reaction between the calcium sulfate & the soluble alginate is prevented as long as there is uncreated trisodium phosphate.alginate is prevented as long as there is uncreated trisodium phosphate. 2Na3Po42Na3Po4 +n CaSo4+n CaSo4 →→nKaSo4nKaSo4 ++Ca. alginateCa. alginate  When the supply of the trisodium phosphate is exhausted, the ca ions beingWhen the supply of the trisodium phosphate is exhausted, the ca ions being to react with the potassium alginate to produce calcium alginate.to react with the potassium alginate to produce calcium alginate. Kzn AlgKzn Alg ++n CaSo4n CaSo4→→ nn KaSo4KaSo4 ++ Cal. alginateCal. alginate  The added salt is retareder.The added salt is retareder.  Controlling of gelation timeControlling of gelation time :-:- 1.1. A increase in the temp. of water used for mixing, shorten ythe working &A increase in the temp. of water used for mixing, shorten ythe working & setting time.setting time. 2.2. The proportion of powder & water also effect the setting time.The proportion of powder & water also effect the setting time. www.indiandentalacademy.comwww.indiandentalacademy.com
  17. 17. PROPERTIESPROPERTIES  Alginate is of two typeAlginate is of two type 1.1. Type I :- Fast settingType I :- Fast setting 2.2. Type II :- N.ormal setting.Type II :- N.ormal setting. According to ADA Specification No. 18 Properties Are:-According to ADA Specification No. 18 Properties Are:- 1.1. Mixing timeMixing time:- Creamy consistency come in 45 – 60 sec.:- Creamy consistency come in 45 – 60 sec. 2.2. Working timeWorking time :-:- - Fast setting material :- 1.2 – 2 min- Fast setting material :- 1.2 – 2 min - Normal set material :- 2 – 4.5 min- Normal set material :- 2 – 4.5 min 3.3. Setting or gelation timeSetting or gelation time :-:- - optimum gelation time :- 3-4 min at room temp.- optimum gelation time :- 3-4 min at room temp. - For fast setting material :- 1 -2 min- For fast setting material :- 1 -2 min - For normal setting material :- 2 – 4.5min- For normal setting material :- 2 – 4.5min www.indiandentalacademy.comwww.indiandentalacademy.com
  18. 18. PROPERTIESPROPERTIES 4.4. Permanent deformationPermanent deformation :- ADA:- ADA specification requires 97% recovery & where 3% is permanent deformation.specification requires 97% recovery & where 3% is permanent deformation. Alginate have 98.8% recovery & 1.5 % permanent deformation.Alginate have 98.8% recovery & 1.5 % permanent deformation. 5.5. FlexibilityFlexibility :- ADA:- ADA specification permits10 – 20% at the stress of 1000gm/ cm2. hard material havespecification permits10 – 20% at the stress of 1000gm/ cm2. hard material have value of 5-8%.value of 5-8%. 6.6. StrengthStrength :-:- The compressive strengthThe compressive strength :- 5000-8000gm/cm2:- 5000-8000gm/cm2 Tear strengthTear strength :- 350-700gm/cm2:- 350-700gm/cm2 7.7.viscoelasticityviscoelasticity :-:- Usually an alginate impression materials does not adhere to the oral tissue asUsually an alginate impression materials does not adhere to the oral tissue as strongly as some of the non aqueous elastomers, so it is easy to remove thestrongly as some of the non aqueous elastomers, so it is easy to remove the alginate impression rapidly.alginate impression rapidly. 8.8. AccuracyAccuracy :-:- Most alginate is not capable of reproducing the finer details that are absorbedMost alginate is not capable of reproducing the finer details that are absorbed in impression with Agar & other elastomeric impression materialin impression with Agar & other elastomeric impression material www.indiandentalacademy.comwww.indiandentalacademy.com
  19. 19. PROPERTIESPROPERTIES 9.9. Dimensional effectsDimensional effects :- -The gel may loss:- -The gel may loss water by evaporation from its surface & it shrinkswater by evaporation from its surface & it shrinks - If the gel placed in the water it absorbed water & gels swells.- If the gel placed in the water it absorbed water & gels swells. - Thermal change also contribute to dimensional change. The- Thermal change also contribute to dimensional change. The alginate shrinks slightly due to different temp. between mouthalginate shrinks slightly due to different temp. between mouth temp.(30temp.(30··c) & room temp(23c) & room temp(23··c).c). 10.10. BiocompatibilityBiocompatibility :-:- No chemical or allergic reaction associated with alginate.No chemical or allergic reaction associated with alginate. 11.11. Self lifeSelf life :-:- Alginate impression have shorter shelf life. Strong temp. &Alginate impression have shorter shelf life. Strong temp. & moisture contamination are two factor which effect the self lifemoisture contamination are two factor which effect the self life of alginate.of alginate. www.indiandentalacademy.comwww.indiandentalacademy.com
  20. 20. MANIPULATION OF ALGINATEMANIPULATION OF ALGINATE PREPARING THE MIXPREPARING THE MIX A measured powder is shifted into preA measured powder is shifted into pre measured water, that has beenmeasured water, that has been placed in a clean rubber bowl. Careplaced in a clean rubber bowl. Care should be taken to avoid whippingshould be taken to avoid whipping air into the mix. A vigorous figure 8air into the mix. A vigorous figure 8 motion is best, with the mix beingmotion is best, with the mix being swiped or stropped against the sideswiped or stropped against the side of the mixing rubber bowl withof the mixing rubber bowl with intermittent rotation ie.180 degree ofintermittent rotation ie.180 degree of the spatula to press out air bubbles.the spatula to press out air bubbles. A mixing time is 45sec -1 min.A mixing time is 45sec -1 min. A variety of mechanical devices areA variety of mechanical devices are also available for mixing impressionalso available for mixing impression material. There benefits arematerial. There benefits are convenience, speed & elimination ofconvenience, speed & elimination of human error.human error. MAKING THE IMPRESSIONMAKING THE IMPRESSION Before setting the impression, theBefore setting the impression, the material should have developedmaterial should have developed sufficient body so that it doesn’tsufficient body so that it doesn’t flow out of the try. A perforated trayflow out of the try. A perforated tray is generally used. If plastic try oris generally used. If plastic try or metal rim lock try is selected a thinmetal rim lock try is selected a thin layer of adhesive should be appliedlayer of adhesive should be applied & allowed to dry before mixing and& allowed to dry before mixing and loading the try. The thickness of theloading the try. The thickness of the alginate between the tray & tissuealginate between the tray & tissue should be at least 3mm.should be at least 3mm. www.indiandentalacademy.comwww.indiandentalacademy.com
  21. 21. MODIFIED ALGINATEMODIFIED ALGINATE  Alginate modified by the incorporation of Silicone. These areAlginate modified by the incorporation of Silicone. These are supplied as two paste which are mixed together. A colorsupplied as two paste which are mixed together. A color contrast between the pastes enable through mixing to becontrast between the pastes enable through mixing to be achieved, although this can be difficult because the pastes areachieved, although this can be difficult because the pastes are of widely differing viscosity in some products.of widely differing viscosity in some products.  To setting characteristics of the modified alginate materials areTo setting characteristics of the modified alginate materials are similar to those of conventional alginate. They show marginallysimilar to those of conventional alginate. They show marginally better fine details, reproduction & tear resistance but have poorbetter fine details, reproduction & tear resistance but have poor dimensional stability. They lose the water as the same rate asdimensional stability. They lose the water as the same rate as convention do. Cast should be poured soon after recordingconvention do. Cast should be poured soon after recording impression if accuracy is to be obtained.impression if accuracy is to be obtained.  This materials are considered as a hybrid of Alginate & SiliconeThis materials are considered as a hybrid of Alginate & Silicone but there properties are close to alginate.but there properties are close to alginate. www.indiandentalacademy.comwww.indiandentalacademy.com
  22. 22. AGAR – REVERSIBLEAGAR – REVERSIBLE HYDROCOLLOIDSHYDROCOLLOIDS  When agar hydrocolloids heated, they liquefyWhen agar hydrocolloids heated, they liquefy or go into the sol state & on cooling theyor go into the sol state & on cooling they return to the gel state. Because this processreturn to the gel state. Because this process can be repeated, a gel of this type iscan be repeated, a gel of this type is described as Reversible hydrocolloid. Thedescribed as Reversible hydrocolloid. The preparation of the agar hydrocolloids forpreparation of the agar hydrocolloids for clinical use requires care full control & yieldsclinical use requires care full control & yields accurate impression. It has been largelyaccurate impression. It has been largely replaced by alginate hydrocolloids & rubberreplaced by alginate hydrocolloids & rubber impression materials.impression materials. www.indiandentalacademy.comwww.indiandentalacademy.com
  23. 23. COMPOSITIONCOMPOSITION 1.1. BoratesBorates :- 0.2 – 0.5%:- 0.2 – 0.5% Its works as retader.Its works as retader. 2.2. waterwater :- 85.5%:- 85.5% It is reaction medium.It is reaction medium. 3.3. AgarAgar:- 13-17%:- 13-17% It is main active constituent of reversible hydrocolloidIt is main active constituent of reversible hydrocolloid impression material.impression material. 4.4. SulfatesSulfates :- 1 – 2%:- 1 – 2% AcceleratorsAccelerators 5.5. FillersFillers :- 0.5 -1%:- 0.5 -1% Diatomaceous earth, silica, wax rubber etc used as filler.Diatomaceous earth, silica, wax rubber etc used as filler. 6.6. BactericideBactericide :-:- Thymol & glycerin are usedThymol & glycerin are used 7.7. Color & flavorColor & flavor www.indiandentalacademy.comwww.indiandentalacademy.com
  24. 24. GELATION PROCESSGELATION PROCESS  The setting of the reversible hydrocolloid is called gelation. TheThe setting of the reversible hydrocolloid is called gelation. The reaction can be expressed a sol- gel reaction. The physicalreaction can be expressed a sol- gel reaction. The physical changes from to gel does not return to the sol at the same temp.changes from to gel does not return to the sol at the same temp. at which it solidified. The gel must be heated at the liquefactionat which it solidified. The gel must be heated at the liquefaction temp. ie 70 - 100temp. ie 70 - 100··c to form sol. Sol transform into a gel at 37-50c to form sol. Sol transform into a gel at 37-50··c.c. the exact gelation temp depended on several factor, including thethe exact gelation temp depended on several factor, including the molecular wt. the purity of the material & the ratio of agar to othermolecular wt. the purity of the material & the ratio of agar to other ingredients.ingredients.  The gelation is critical. If the temp. is high, the heat from sol mayThe gelation is critical. If the temp. is high, the heat from sol may injury to the soft tissue, or if the surface of the sol transforms to ainjury to the soft tissue, or if the surface of the sol transforms to a gel as soon as the sol may injure the oral tissues, a high surfacegel as soon as the sol may injure the oral tissues, a high surface stress may develop. If the gelation temp. is too far below the oralstress may develop. If the gelation temp. is too far below the oral temp. it will be difficulty or even impossible to chill the materialtemp. it will be difficulty or even impossible to chill the material sufficiently to obtain a firm gel to adjacent to the oral tissue. Thesufficiently to obtain a firm gel to adjacent to the oral tissue. The temp. lag between the gelation & liquefaction temp. of the geltemp. lag between the gelation & liquefaction temp. of the gel makes it possible to use as a dental impression material.makes it possible to use as a dental impression material. www.indiandentalacademy.comwww.indiandentalacademy.com
  25. 25. PROPERTIESPROPERTIES  Gelation temperatureGelation temperature :-:- After tempering the sol should be homogenous and should set to a gel betweenAfter tempering the sol should be homogenous and should set to a gel between 37 – 50 degrees centigrade37 – 50 degrees centigrade when cooled.when cooled.  Viscoelastic propertiesViscoelastic properties :-:- It demonstrate the necessity of deforming the impression rapidly when itIt demonstrate the necessity of deforming the impression rapidly when it removed from the mouth which reduce the amount of the permanentremoved from the mouth which reduce the amount of the permanent deformation. The elastic recovery of the hydrocolloid is never complete & itdeformation. The elastic recovery of the hydrocolloid is never complete & it does not return entirely to its original dimension after deformation. The amountdoes not return entirely to its original dimension after deformation. The amount of permanent deformation in clinical is negligible, provided that :-of permanent deformation in clinical is negligible, provided that :- a) The material has adequately gelled.a) The material has adequately gelled. b) The impression has been removed rapidly.b) The impression has been removed rapidly. c) The under cuts present in the cavity preparation are minimal.c) The under cuts present in the cavity preparation are minimal.  Permanent deformationPermanent deformation :-:- The ADA specification requires that the permanent deformation should be lessThe ADA specification requires that the permanent deformation should be less than 1.5% after the material compressed 10% for 30sec. This impressionthan 1.5% after the material compressed 10% for 30sec. This impression material readily meet this requirement with the value of about 1%.material readily meet this requirement with the value of about 1%.  Distortion during gelationDistortion during gelation :-:- If the material is held rigidly to the tray , then the impression material shrinksIf the material is held rigidly to the tray , then the impression material shrinks toward the center of its mass. Rapid cooling may cause a concentration oftoward the center of its mass. Rapid cooling may cause a concentration of stress near the tray where gelation first take place.stress near the tray where gelation first take place. www.indiandentalacademy.comwww.indiandentalacademy.com
  26. 26. PROPERTIESPROPERTIES  FlexibilityFlexibility :-:- The ADA specification requirement for flexibility allows a rangeThe ADA specification requirement for flexibility allows a range of 4-14% & most agar materials meet this requirement.of 4-14% & most agar materials meet this requirement.  StrengthStrength :-:- 1.1. The compressive strength of Agar impression material isThe compressive strength of Agar impression material is 8000gm/cm28000gm/cm2 2.2. The tear strength of Agar is 7000gm/cm2The tear strength of Agar is 7000gm/cm2  FlowFlow :-:- Agar is sufficiently fluid to allow detailed reproduction of hardAgar is sufficiently fluid to allow detailed reproduction of hard & soft tissue.& soft tissue.  Compatibility with gypsumCompatibility with gypsum :-:- Not all the agar impression materials are equally compatibleNot all the agar impression materials are equally compatible with all gypsum products. The impression should be washedwith all gypsum products. The impression should be washed of saliva & any trace of blood, which retarded the setting ofof saliva & any trace of blood, which retarded the setting of gypsum.gypsum. www.indiandentalacademy.comwww.indiandentalacademy.com
  27. 27. Manipulation of agar impression:Manipulation of agar impression: The use of agar hydrocolloid involveThe use of agar hydrocolloid involve special equipment called conditioning unitspecial equipment called conditioning unit for agar. The hydrocolloid is usuallyfor agar. The hydrocolloid is usually supplied In two forms: syringe and traysupplied In two forms: syringe and tray materials. The only difference between thematerials. The only difference between the materials is the color and the greatermaterials is the color and the greater fluidity of the syringe material.fluidity of the syringe material. www.indiandentalacademy.comwww.indiandentalacademy.com
  28. 28. Impression tray:Impression tray: It is rim locked trays with water circulatingIt is rim locked trays with water circulating device. This types of trays should allow adevice. This types of trays should allow a space of 3mm occlusally and laterally andspace of 3mm occlusally and laterally and extend distally to cover all the teeth. Afterextend distally to cover all the teeth. After the tray has been properly positioned,the tray has been properly positioned, water is circulated at 13 degrees throughwater is circulated at 13 degrees through the tray until gelation occurs.the tray until gelation occurs. www.indiandentalacademy.comwww.indiandentalacademy.com
  29. 29. Preparation of material:Preparation of material: Proper equipment of liquefying andProper equipment of liquefying and storing the agar impressionstoring the agar impression material is essential.material is essential. At first reverse the hydrocolloid gelAt first reverse the hydrocolloid gel to the sol stage. Boiling water is ato the sol stage. Boiling water is a convenient way of liquefying theconvenient way of liquefying the material. The material must bematerial. The material must be held at this temperature for aheld at this temperature for a minimum of 10mins. Propyleneminimum of 10mins. Propylene glycol can be added to the waterglycol can be added to the water to obtain 100 degrees. After it hasto obtain 100 degrees. After it has been liquefied, the material mustbeen liquefied, the material must be stored in the tray. The materialbe stored in the tray. The material can be stored for several days.can be stored for several days. Usually, there are threeUsually, there are three compartments in the conditioningcompartments in the conditioning unit, making it possible to liquefy,unit, making it possible to liquefy, store and temper the material.store and temper the material. www.indiandentalacademy.comwww.indiandentalacademy.com
  30. 30. Conditioning and tempering:Conditioning and tempering: Because 55 degree is the maximum tolerableBecause 55 degree is the maximum tolerable temperature, the storage temperature of 65temperature, the storage temperature of 65 degrees would be too hot for the oral tissues,degrees would be too hot for the oral tissues, especially given the bulk of the tray material.especially given the bulk of the tray material. Therefore, the material that is used to fill the trayTherefore, the material that is used to fill the tray must be cooled and tempered. Eliminating themust be cooled and tempered. Eliminating the effect of imbibition is the purpose of placing theeffect of imbibition is the purpose of placing the gauze pad over the tempering tray materials.gauze pad over the tempering tray materials. When the tray material is placed into theWhen the tray material is placed into the tempering bath, the gauze is removed and thetempering bath, the gauze is removed and the contaminating surface layer of material clings tocontaminating surface layer of material clings to the gauze and is removed as well.the gauze and is removed as well. www.indiandentalacademy.comwww.indiandentalacademy.com
  31. 31. Making the impression:Making the impression: The syringe material is taken directly from theThe syringe material is taken directly from the storage compartment and applied to thestorage compartment and applied to the prepared cavities. It is first applied to the base ofprepared cavities. It is first applied to the base of the preparation and then the reminder of thethe preparation and then the reminder of the tooth is covered. By the time the cavitytooth is covered. By the time the cavity preparation and adjoining teeth have beenpreparation and adjoining teeth have been covered, the tray material has been properlycovered, the tray material has been properly tempered and is now ready to be placedtempered and is now ready to be placed immediately in the mouth to form the bulk ofimmediately in the mouth to form the bulk of impression. Gelation is accelerated byimpression. Gelation is accelerated by circulating cool water, approximately, 18 – 21circulating cool water, approximately, 18 – 21 degrees through the tray for 3 – 5 minutesdegrees through the tray for 3 – 5 minutes.. www.indiandentalacademy.comwww.indiandentalacademy.com
  32. 32. Disinfection hydrocolloidDisinfection hydrocolloid impression:impression: .. As the hydrocolloid impression material must be pouredAs the hydrocolloid impression material must be poured within short time after removal from the mouth. Thewithin short time after removal from the mouth. The disinfection procedure should be relatively rapid todisinfection procedure should be relatively rapid to prevent the dimensional change. Most manufacturersprevent the dimensional change. Most manufacturers recommended a specific disinfectant. The agent may berecommended a specific disinfectant. The agent may be iodophor, bleach or glutaraldehyde. The distortion isiodophor, bleach or glutaraldehyde. The distortion is minimal if the recommended immersion time is followedminimal if the recommended immersion time is followed and if the impression is poured properly. The irreversibleand if the impression is poured properly. The irreversible hydrocolloid may be disinfected by 10 minute immersionhydrocolloid may be disinfected by 10 minute immersion in/or spraying with the antimicrobial agent such as NaOClin/or spraying with the antimicrobial agent such as NaOCl and glutaraldehyde without sufficient dimensional change.and glutaraldehyde without sufficient dimensional change. The current protocol for disinfecting hydrocolloidThe current protocol for disinfecting hydrocolloid impression is to use household bleach, iodophor, andimpression is to use household bleach, iodophor, and synthetic phenols as disinfectants. After the immersion, itsynthetic phenols as disinfectants. After the immersion, it is thoroughly rinsed . The disinfectant is sprayed liberallyis thoroughly rinsed . The disinfectant is sprayed liberally o the exposed surface. The immersion should not beo the exposed surface. The immersion should not be submerged or shocked in the disinfectant solution.submerged or shocked in the disinfectant solution.www.indiandentalacademy.comwww.indiandentalacademy.com
  33. 33. ADVANTAGES & DISADVANTAGEADVANTAGES & DISADVANTAGE ImpressionImpression materialsmaterials Brand nameBrand name AdvantagesAdvantages DisadvantageDisadvantage ReversibleReversible hydrocolloidhydrocolloid AgarAgar 1. Acculoid /1. Acculoid / CartriloidsCartriloids (Van R)(Van R) 2. Indentic2. Indentic (cadco)(cadco) 1. Moist field ok1. Moist field ok 2. Accurate2. Accurate replicareplica 3. Hydrophilic3. Hydrophilic 4.low cost4.low cost 5. long self life5. long self life 1. Require1. Require specialspecial equipmentequipment 2. thermal2. thermal discomfortdiscomfort 3. Tears easily3. Tears easily 4. Must be4. Must be pouredpoured immediatelyimmediately IrreversibleIrreversible hydrocolloidhydrocolloid AlginateAlginate 1. Coe Alginate1. Coe Alginate (GC America)(GC America) 2. Integra2. Integra (Kerr) 3. Super(Kerr) 3. Super gel (Bosworth)gel (Bosworth) 1.1. Moist fieldMoist field okok 2. Clean replica2. Clean replica 3. Hydrophilic3. Hydrophilic 4. Low cost4. Low cost 5 Patient5 Patient acceptanceacceptance 1.1. NotNot accurate /accurate / roughrough reproductionreproduction 2. Tear easily2. Tear easily 3. Must poured3. Must poured immediatelyimmediatelywww.indiandentalacademy.comwww.indiandentalacademy.com
  34. 34. TYPES OF FALIURESTYPES OF FALIURES 1.1.DistortionDistortion :- due to:- due to  Delayed pouring of impressionDelayed pouring of impression  Movement of tray during settingMovement of tray during setting  Removal from mouth too earlyRemoval from mouth too early 2.Grainy impression2.Grainy impression :- due to:- due to  Inadequate mixingInadequate mixing  Prolonged mixingProlonged mixing  Less water in mixLess water in mix 3.3. TearingTearing :- due to:- due to  Inadequate bulkInadequate bulk  Moisture contaminationMoisture contamination  Removal from mouth too earlyRemoval from mouth too early  Prolonged mixingProlonged mixing 4.4. BubblesBubbles :- due to:- due to  Early gelation, preventing flowEarly gelation, preventing flow  Air incorporated during mixingAir incorporated during mixing 5.5. Irregular voidsIrregular voids :- due to:- due to  Excess moisture &debris on tissueExcess moisture &debris on tissue www.indiandentalacademy.comwww.indiandentalacademy.com
  35. 35. INELASTIC OR RIGIEDINELASTIC OR RIGIED IMPRESSION MATERIALIMPRESSION MATERIAL In elastic impression materials exhibit anIn elastic impression materials exhibit an insignificant of elastic deformation wheninsignificant of elastic deformation when subjected to bonding or tensile strength. Theysubjected to bonding or tensile strength. They tend to fracture without exhibiting any plastictend to fracture without exhibiting any plastic deformation if the stress applied pressuredeformation if the stress applied pressure exceeds there tensile, shear or compressiveexceeds there tensile, shear or compressive strength value. These material includestrength value. These material include Impression compound, Impression plaster &Impression compound, Impression plaster & ZOE impression paste. Because of theseZOE impression paste. Because of these materials inability to sustain a substantialmaterials inability to sustain a substantial amount of elastic deformation without fracture,amount of elastic deformation without fracture, there use in dental impression making is limited.there use in dental impression making is limited. www.indiandentalacademy.comwww.indiandentalacademy.com
  36. 36. Impression compoundImpression compound  Impression compound is aImpression compound is a thermoplastic material. When itsthermoplastic material. When its used for edentulous impression, itused for edentulous impression, it is also called modeling plastic. Itsis also called modeling plastic. Its classified as a rigid, reversibleclassified as a rigid, reversible impression material which sets byimpression material which sets by physical change. It usually comesphysical change. It usually comes in the form cakes & sticks.in the form cakes & sticks.  CLASSIFICATIONCLASSIFICATION According to ADA specification no.3According to ADA specification no.3 dental impression compounds aredental impression compounds are classified into two types :-classified into two types :- 1.1. Type I Impression compoundType I Impression compound :- It:- It is used for making edentulousis used for making edentulous impression. It is also used to makeimpression. It is also used to make impression of single tooth inimpression of single tooth in operative dentistry.operative dentistry. 2.2. Type II Tray compoundType II Tray compound :- It is a try:- It is a try compound which is used tocompound which is used to prepare a try for making aprepare a try for making a impression.impression. www.indiandentalacademy.comwww.indiandentalacademy.com
  37. 37. REQUIREMENT OF IDEALREQUIREMENT OF IDEAL IMPRESSION COMPOUNDIMPRESSION COMPOUND 1.1. Solidified or harden at or little above mouth temp.Solidified or harden at or little above mouth temp. 2.2. Not injurious or harmful to oral tissue.Not injurious or harmful to oral tissue. 3.3. Not contain irritating or toxic ingredient.Not contain irritating or toxic ingredient. 4.4. Harden uniformly when cooled without distortion.Harden uniformly when cooled without distortion. 5.5. Reproduce fine detail.Reproduce fine detail. 6.6. Cohesive but not adhesive.Cohesive but not adhesive. 7.7. Should not undergo permanent deformation.Should not undergo permanent deformation. 8.8. Good dimensional stabilityGood dimensional stability 9.9. Smooth glossy surfaceSmooth glossy surface 10.10. After hardening should withstand trimming with sharpAfter hardening should withstand trimming with sharp knife chippingknife chipping www.indiandentalacademy.comwww.indiandentalacademy.com
  38. 38. COPOSITIONCOPOSITION 1.1. Thermoplastic materialThermoplastic material:- 50%:- 50% Natural or synthetic resins & waxes areNatural or synthetic resins & waxes are usedused 2.2. FillerFiller :- 47%:- 47% These are talcThese are talc 3.3. LubricantLubricant :- 3%:- 3% Stearic acid usedStearic acid used www.indiandentalacademy.comwww.indiandentalacademy.com
  39. 39. PROPERTIESPROPERTIES 1.1. Thermal propertiesThermal properties :-:- It is very low. The coefficient of contraction of impressionIt is very low. The coefficient of contraction of impression compound is from mouth temp. to room temp. is 0.3%compound is from mouth temp. to room temp. is 0.3% 2.2. FlowFlow :-:- According to ADA specification no. 3 flow should be:-According to ADA specification no. 3 flow should be:- Type I :- Not more than 6% at 37degreeType I :- Not more than 6% at 37degree Not less than 80% & not more thanNot less than 80% & not more than 85% at 45degree.85% at 45degree. Type II :- Not more than 2% at 37degreeType II :- Not more than 2% at 37degree Not less than 70% & not more than 85% at 45degreeNot less than 70% & not more than 85% at 45degree 3.3. DistortionDistortion :-:- The release of strains is avoidable, the safest procedure toThe release of strains is avoidable, the safest procedure to prevent distortion is to pour the cast immediately or at least in 1prevent distortion is to pour the cast immediately or at least in 1 hrs.hrs. 4.4. Dimensionally stabilityDimensionally stability :-:- Relaxation of the impression compound can occur in aRelaxation of the impression compound can occur in a comparatively short period of time, especial with increase in temp.comparatively short period of time, especial with increase in temp. 5.5. ViscosityViscosity :-:- The most viscose material. 70 time more than impression & 100The most viscose material. 70 time more than impression & 100 time more than light body elastomers.time more than light body elastomers. www.indiandentalacademy.comwww.indiandentalacademy.com
  40. 40. DISINFECTIONDISINFECTION  The recommended disinfectant solution for compound is 2% alkalineThe recommended disinfectant solution for compound is 2% alkaline glutaraldehyde solution. The impression should immersed in this solution forglutaraldehyde solution. The impression should immersed in this solution for the require amount of time, rinsed & poured immediately.the require amount of time, rinsed & poured immediately. MANIPULATIONMANIPULATION Small amount of compound is soften over the flame. When a direct flame isSmall amount of compound is soften over the flame. When a direct flame is used, the compound should not allowed to boil or ignite, other wise theused, the compound should not allowed to boil or ignite, other wise the plasticizers are volatilized.plasticizers are volatilized.  When a large amount of compound is to be softened, it is difficult to heatWhen a large amount of compound is to be softened, it is difficult to heat uniformly. The compound is softened in a thermostatically controlled wateruniformly. The compound is softened in a thermostatically controlled water bath. After the compound is removed from the water, it is usually kneadedbath. After the compound is removed from the water, it is usually kneaded with the finger to obtain uniform plasticity throughout the mass.with the finger to obtain uniform plasticity throughout the mass.  The safest method for removing the cast from is to immerse it in warm waterThe safest method for removing the cast from is to immerse it in warm water until the compound softens sufficiently to permit easy separation from cast.until the compound softens sufficiently to permit easy separation from cast. www.indiandentalacademy.comwww.indiandentalacademy.com
  41. 41. ZINC OXIED EUGENOL IMPRESSIONZINC OXIED EUGENOL IMPRESSION PASTEPASTE  Under proper condition, the reaction betweenUnder proper condition, the reaction between zinc oxide & eugenol yields a relatively hardzinc oxide & eugenol yields a relatively hard mass that possesses certain medicinalmass that possesses certain medicinal advantage, as well as mechanical propertiesadvantage, as well as mechanical properties benefits, for some dental operation. ZOEbenefits, for some dental operation. ZOE impression paste produces a rigid impressionimpression paste produces a rigid impression with a high degree of accuracy & goodwith a high degree of accuracy & good reproduction of surface detail.reproduction of surface detail.  Types of paste:-Types of paste:- 1.1. Type I:- hardType I:- hard 2.2. Type II :- softType II :- soft www.indiandentalacademy.comwww.indiandentalacademy.com
  42. 42. COPOSITIONCOPOSITION Usually its come in two tube in paste formUsually its come in two tube in paste form  Base pasteBase paste :- its in white in color:- its in white in color 1.1. Zinc oxideZinc oxide :- 87%:- 87% 2.2. Fixed vegetable or mineral oilFixed vegetable or mineral oil :- 13%:- 13%  Accelerator pasteAccelerator paste:- it is in red color:- it is in red color 1.1. Oil of clovesOil of cloves:- 12%:- 12% contains 70 – 85% eugenol oilcontains 70 – 85% eugenol oil 2.2. Gum or polymerized rosinGum or polymerized rosin :- 50%:- 50% 3.3. FillerFiller :- 20%:- 20% its silica typeits silica type 4.4. LanolinLanolin :- 3%:- 3% 5.5. Resinous balsamResinous balsam:- 10%:- 10% 6.6. Accelerator solutionAccelerator solution:- 5%:- 5% www.indiandentalacademy.comwww.indiandentalacademy.com
  43. 43. MANIPULATIONMANIPULATION  The mixing of two paste isThe mixing of two paste is generally accomplished on angenerally accomplished on an oil impervious paper or glassoil impervious paper or glass slab. The proper proportion ofslab. The proper proportion of the two pastes is generallythe two pastes is generally obtained by squeezing twoobtained by squeezing two strips of paste of the samestrips of paste of the same length, one from each tube onlength, one from each tube on the mixing slab. A flexiblethe mixing slab. A flexible stainless steal spatula isstainless steal spatula is typically used for the mixingtypically used for the mixing procedure. The two strip ofprocedure. The two strip of contrasting color are combinedcontrasting color are combined with the first stroke of thewith the first stroke of the spatula & the mixing isspatula & the mixing is continued for approx 1 min orcontinued for approx 1 min or uniform color is obtained.uniform color is obtained. www.indiandentalacademy.comwww.indiandentalacademy.com
  44. 44. PROPERTIESPROPERTIES 1.1. Setting timeSetting time:-:- Once the material in a plastic condition is carried to the mouth, only theOnce the material in a plastic condition is carried to the mouth, only the minimum time should elapse before the impression harden.minimum time should elapse before the impression harden.  Initial setting timeInitial setting time :-:- Type I :- 3 – 6minType I :- 3 – 6min type II :- 3 – 6mintype II :- 3 – 6min  Final setting timeFinal setting time :-:- Type I :- 10minType I :- 10min Type II :- 15minType II :- 15min This setting time is at 23 degreeThis setting time is at 23 degree ± 2degree & 50% humidity.± 2degree & 50% humidity. 2.2. Consistency & flowConsistency & flow :-:- According to ADA specification no. 16 its spread –According to ADA specification no. 16 its spread – Type IType I :- 30 – 50mm:- 30 – 50mm Type II :- 20 45 mmType II :- 20 45 mm 3.3. Rigidity & strengthRigidity & strength :-:- The compressive strength of ZOE paste is 7Mpa 2 hrs after mixingThe compressive strength of ZOE paste is 7Mpa 2 hrs after mixing 4.4. Dimensional stabilityDimensional stability :-:- it is quit satisfactory. Shrinkage is less than 0.1%.it is quit satisfactory. Shrinkage is less than 0.1%. www.indiandentalacademy.comwww.indiandentalacademy.com
  45. 45. DISINFECTIONDISINFECTION The recommended disinfectant solution forThe recommended disinfectant solution for ZOE impression paste is 2% alkalineZOE impression paste is 2% alkaline glutaraldehyde solution. The impressionglutaraldehyde solution. The impression should immersed in this solution forshould immersed in this solution for required amount of time, rinsed & pouredrequired amount of time, rinsed & poured immediately.immediately. www.indiandentalacademy.comwww.indiandentalacademy.com
  46. 46. NON EUGENOL PASTENON EUGENOL PASTE One of the chief disadvantage of ZOE paste isOne of the chief disadvantage of ZOE paste is the possible burning sensation caused by thethe possible burning sensation caused by the eugenol that leaches out & contact the softeugenol that leaches out & contact the soft tissue. Zinc oxide can react with varioustissue. Zinc oxide can react with various carboxylic acid & form ZOE like structure.carboxylic acid & form ZOE like structure. Orthoethoxy benzoic acid, commonlyOrthoethoxy benzoic acid, commonly abbreviated EBA, is the valuable substitute forabbreviated EBA, is the valuable substitute for eugenol in this regard. The reaction is welleugenol in this regard. The reaction is well understood & its not greatly affected by temp. orunderstood & its not greatly affected by temp. or humidity. Bactericidal agents & otherhumidity. Bactericidal agents & other medicaments can be incorporated withoutmedicaments can be incorporated without interfering the reaction.interfering the reaction. www.indiandentalacademy.comwww.indiandentalacademy.com
  47. 47. BITE REGISTRATION PASTEBITE REGISTRATION PASTE The materials used for recording theThe materials used for recording the occlusal relationship between natural &occlusal relationship between natural & artificial teeth including impression plaster,artificial teeth including impression plaster, compound, wax- ZOE paste, often usedcompound, wax- ZOE paste, often used as recording materials in the constructionas recording materials in the construction of complete dentures, & fixed or removalof complete dentures, & fixed or removal partial denture. The ZOE paste offerspartial denture. The ZOE paste offers almost no resistance to closing of thealmost no resistance to closing of the mandible. Thus allowing a more accuratemandible. Thus allowing a more accurate interocclusion recording to be formed.interocclusion recording to be formed. www.indiandentalacademy.comwww.indiandentalacademy.com
  48. 48. ELASTOMERIC IMPRESSIONELASTOMERIC IMPRESSION MATERIALMATERIAL  Elastomers refer to a group of rubbery polymers, which are either chemically orElastomers refer to a group of rubbery polymers, which are either chemically or physically cross linked. They can be easily stretched & rapidly recover theirphysically cross linked. They can be easily stretched & rapidly recover their original dimensions when the applied stress is removed. Chemically there are fouroriginal dimensions when the applied stress is removed. Chemically there are four types of elastomers used as Impression material-types of elastomers used as Impression material- 1.1. PolysulfidePolysulfide 2.2. Condensation polymerizing siliconesCondensation polymerizing silicones 3.3. Addition polymerizing siliconesAddition polymerizing silicones 4.4. PolyetherPolyether  The current ADA specification no. 19 recognizes three types of elatomericThe current ADA specification no. 19 recognizes three types of elatomeric impression materials. Classification is based on selected elastic properties & theimpression materials. Classification is based on selected elastic properties & the dimensional change of the set materials rather than there chemistry. Each type isdimensional change of the set materials rather than there chemistry. Each type is further divided into four viscosity classes :-further divided into four viscosity classes :- 1.1. Light bodyLight body 2.2. Medium or regular bodyMedium or regular body 3.3. Heavy bodyHeavy body 4.4. puttyputty www.indiandentalacademy.comwww.indiandentalacademy.com
  49. 49. Properties of ElastomericProperties of Elastomeric Impression MaterialImpression Material 1.1. Excellent reproduction ability of surface detailExcellent reproduction ability of surface detail 2.2. HydrophobicHydrophobic 3.3. Elastic properties is good but elastic recovery is not complete.Elastic properties is good but elastic recovery is not complete. 4.4. Coefficient of thermal expansion is high.Coefficient of thermal expansion is high. 5.5. Dimensional changes occurs due to:-Dimensional changes occurs due to:-  Curing shrinkageCuring shrinkage  Absorb water & loses soluble plasticizers causes change.Absorb water & loses soluble plasticizers causes change.  Due to thermal contraction.Due to thermal contraction.  Incomplete elastic recovery.Incomplete elastic recovery.  When filler content is increased, the polymer content is less &When filler content is increased, the polymer content is less & shrinkage is less.shrinkage is less.  Uniform thickness of material gives more accurate impression asUniform thickness of material gives more accurate impression as the shrinkage is uniform.the shrinkage is uniform.  Good adhesion to the tray with the help of adhesives.Good adhesion to the tray with the help of adhesives. www.indiandentalacademy.comwww.indiandentalacademy.com
  50. 50. POLYSULFIED IMPRESSIONPOLYSULFIED IMPRESSION  This was the first elastomeric impressionThis was the first elastomeric impression material to be introduced. It is also know asmaterial to be introduced. It is also know as MERCAPTAN or THIOKOL.MERCAPTAN or THIOKOL.  MODE OF SUPPLYMODE OF SUPPLY it is supplied in collapsible tube as base &it is supplied in collapsible tube as base & accelerator in paste form. Base in white coloraccelerator in paste form. Base in white color & accelerator is in gray color. It is available in& accelerator is in gray color. It is available in three viscosities:-three viscosities:- 1.1. Light bodiedLight bodied 2.2. Medium bodiedMedium bodied 3.3. Heavy bodiedHeavy bodied www.indiandentalacademy.comwww.indiandentalacademy.com
  51. 51. COMPOSITIONCOMPOSITION  BASE PASTEBASE PASTE 1.1. Liquid polysulfide polymerLiquid polysulfide polymer:-80:-80 -85%-85% 2.2. Inert fillerInert filler :- 16 – 18%:- 16 – 18% TitaniumTitanium dioxide, zinc sulfate, copperdioxide, zinc sulfate, copper carbonate use as a fillercarbonate use as a filler 3. Plasticize3. Plasticize  ACCELERATOR orACCELERATOR or CATALYST PASTECATALYST PASTE 1.1. Lead dioxideLead dioxide:- 60 – 68%:- 60 – 68% 2.2. SulfurSulfur :- 3%:- 3% 3.3. Inert oilInert oil:- 30 -35%:- 30 -35% Normally itNormally it is Paraffinic type or di-n-is Paraffinic type or di-n- butyl phthalate.butyl phthalate. www.indiandentalacademy.comwww.indiandentalacademy.com
  52. 52. CHEMISTRYCHEMISTRY  The main component of polysulfide material is aThe main component of polysulfide material is a multifunctional mercaptan or polysulfide polymer. Thismultifunctional mercaptan or polysulfide polymer. This liner polymer contains approximately 1 mole percent ofliner polymer contains approximately 1 mole percent of pendent- Thiol group(-SH gp). A oxidizing agent such aspendent- Thiol group(-SH gp). A oxidizing agent such as lead dioxide is used to initiate polymerization throughlead dioxide is used to initiate polymerization through chain lengthening between terminal – SH gp. & crosschain lengthening between terminal – SH gp. & cross linked between the pendant – SH gp. Lead dioxide is thelinked between the pendant – SH gp. Lead dioxide is the component that gives polysulfide. The reaction starts atcomponent that gives polysulfide. The reaction starts at the beginning of mixing & reaches its maximum ratethe beginning of mixing & reaches its maximum rate soon after the spatulation is completed. During the finalsoon after the spatulation is completed. During the final set, a material of adequate elasticity & strength isset, a material of adequate elasticity & strength is formed. Moisture & temp. have a significant effect on theformed. Moisture & temp. have a significant effect on the course of the reaction.course of the reaction. www.indiandentalacademy.comwww.indiandentalacademy.com
  53. 53. PROPERTIESPROPERTIES 1.1. Setting timeSetting time:-:- 16 min at 23 degree16 min at 23 degree 12.5 min at 37 degree12.5 min at 37 degree 2.2. Working timeWorking time :-:- 6 min at 23 degree6 min at 23 degree 4.3 min at 37 degree4.3 min at 37 degree 3.3. Taste & odorTaste & odor :-:- Taste less with sulphours odor.Taste less with sulphours odor. 4.4. Excellent quality of reproduction of surface details.Excellent quality of reproduction of surface details. 5.5. Dimensional stabilityDimensional stability:-:- The curing shrinkage is high. It is 0.45%The curing shrinkage is high. It is 0.45% The material has highest permanent deformationThe material has highest permanent deformation among the elastomers & it is 3 – 5%among the elastomers & it is 3 – 5% www.indiandentalacademy.comwww.indiandentalacademy.com
  54. 54. PROPERTIESPROPERTIES 6.6. Tear strengthTear strength :-:- it is high. It is 2500 – 7000M/nit is high. It is 2500 – 7000M/n 7.7. Good flexibility of 7%Good flexibility of 7% 8.8. HydrophobicHydrophobic 9.9. Shelf life is 2 years.Shelf life is 2 years. 10.10. BiocompatibilityBiocompatibility :-:- the use of lead compound in polysulfide material hasthe use of lead compound in polysulfide material has been questioned because of the know toxic effect ofbeen questioned because of the know toxic effect of lead. It is unlikely that the lead contained in thislead. It is unlikely that the lead contained in this material is able to exert a harmful effect as the materialmaterial is able to exert a harmful effect as the material is in the patient mouth for only a few min.is in the patient mouth for only a few min. 11.11. Coefficient of thermal expansionCoefficient of thermal expansion :-:- is 270is 270 x 10-6 degree centigrade -1x 10-6 degree centigrade -1 12.12. Stress relaxation at 2 min after setting time is 45%Stress relaxation at 2 min after setting time is 45% www.indiandentalacademy.comwww.indiandentalacademy.com
  55. 55. SILICONE RUBBER IMPRESIONSILICONE RUBBER IMPRESION MATERIALMATERIAL  These materials were developed to overThese materials were developed to over come some of disadvantages ofcome some of disadvantages of Polysulfide.Polysulfide.  These are of two type:-These are of two type:- 1.1. Condensation siliconeCondensation silicone 2.2. Addition siliconeAddition silicone www.indiandentalacademy.comwww.indiandentalacademy.com
  56. 56. CONDENSATION SILICONECONDENSATION SILICONE  This was the earlier of the two silicone impressionThis was the earlier of the two silicone impression material. It is also known as convention silicone.material. It is also known as convention silicone.  Mode of supply :-Mode of supply :- This material is available as base & catalyst in paste form.This material is available as base & catalyst in paste form. Catalyst can also be supplied in liquid form. It isCatalyst can also be supplied in liquid form. It is available in three viscosities –available in three viscosities – 1. Light bodies1. Light bodies 2. Medium bodies2. Medium bodies 3. Putty3. Putty  Commercial name :- Sil21 & ColtexCommercial name :- Sil21 & Coltex www.indiandentalacademy.comwww.indiandentalacademy.com
  57. 57. COMPOSITIONCOMPOSITION  BASEBASE 1.1. Hydroxyl terminated polydimethylHydroxyl terminated polydimethyl siloxanesiloxane :-:- 2.2. Inert fillerInert filler :-:- Silica is use as a fillerSilica is use as a filler  ACCELERATOR OR CATALYST PASTEACCELERATOR OR CATALYST PASTE 1.1. Ortho ethyl silicateOrtho ethyl silicate 2.2. Stannous octoateStannous octoate www.indiandentalacademy.comwww.indiandentalacademy.com
  58. 58. CHEMISTRYCHEMISTRY  It is a condensation reaction. PolymerizationIt is a condensation reaction. Polymerization occurs as a result of cross linkage between theoccurs as a result of cross linkage between the orthoethyl silicate & the terminal hydroxy grouporthoethyl silicate & the terminal hydroxy group of the dimethyl silicone, to form a threeof the dimethyl silicone, to form a three dimensional network. Stannous octoate act as adimensional network. Stannous octoate act as a catalyst.catalyst.  The ethyl alcohol formed as a by productThe ethyl alcohol formed as a by product evaporate gradually from the set rubber leadingevaporate gradually from the set rubber leading to shrinkage.to shrinkage. www.indiandentalacademy.comwww.indiandentalacademy.com
  59. 59. PROPERTIESPROPERTIES 1.1. Working timeWorking time:-:- it is 3.3 min at 23 degreeit is 3.3 min at 23 degree it is 2.5 min at 37degreeit is 2.5 min at 37degree 2.2. Setting timeSetting time :-:- it is 11 min at 23degreeit is 11 min at 23degree it is 8.9 min at 37 degreeit is 8.9 min at 37 degree 3.3. Odour less, taste less with wide variety of colorOdour less, taste less with wide variety of color 4.4. Excellent quality of reproduction of surfaceExcellent quality of reproduction of surface details.details. 5.5. Dimensional stabilityDimensional stability :-:- It is less due to high curing shrinkage. CuringIt is less due to high curing shrinkage. Curing shrinkage is 0.4 – 0.6% Permanentshrinkage is 0.4 – 0.6% Permanent deformation is high with 1 – 3%deformation is high with 1 – 3%www.indiandentalacademy.comwww.indiandentalacademy.com
  60. 60. PROPERTIESPROPERTIES 6.6. Tear strengthTear strength :-:- 2300 – 2600N/m2300 – 2600N/m 7. More stiffer & harder than the polysulfide7. More stiffer & harder than the polysulfide 8. Hydrophobic8. Hydrophobic 9.9. BiocompatibilityBiocompatibility :-:- Essentially considered nontoxic, despite the fact thatEssentially considered nontoxic, despite the fact that they contain a heavy metal catalyst. The materials arethey contain a heavy metal catalyst. The materials are hydrophobic & are in the patient mouth for only a fewhydrophobic & are in the patient mouth for only a few min.min. 10.10. Coefficient of thermal expansionCoefficient of thermal expansion :-:- 190190x10-6 degree centigrade -1x10-6 degree centigrade -1 11. Loss of weight of this material at 24 hrs is 0.9%11. Loss of weight of this material at 24 hrs is 0.9% 12. shelf life is 12 month.12. shelf life is 12 month. www.indiandentalacademy.comwww.indiandentalacademy.com
  61. 61. ADDITIONADDITION SILICONESILICONE  It has a better propertiesIt has a better properties than condensation silicones.than condensation silicones. It is also know as POLYIt is also know as POLY VINYL SILOXANE.VINYL SILOXANE.  MODE OF SUPPLYMODE OF SUPPLY Addition silicone materialsAddition silicone materials are available as Base &are available as Base & Catalyst in paste form. It isCatalyst in paste form. It is available in four viscosities:-available in four viscosities:- 1.1. Light bodiedLight bodied 2.2. Medium bodiedMedium bodied 3.3. Heavy bodiedHeavy bodied 4.4. PuttyPutty  Commercial names:-Commercial names:- 1.1. ReprosilReprosil 2.2. ProvilProvil 3.3. presidentpresident www.indiandentalacademy.comwww.indiandentalacademy.com
  62. 62. COMPOSITIONCOMPOSITION  BASEBASE 1.1. Poly methyl hydrogen siloxanePoly methyl hydrogen siloxane 2.2. Other siloxane prepolymersOther siloxane prepolymers 3.3. FillersFillers  CATALYSTCATALYST 1.1. Divinyl polysiloxaneDivinyl polysiloxane 2.2. Other siloxane prepolymersOther siloxane prepolymers 3.3. Platinum saltPlatinum salt 4.4. Palladium or hydrogen absorberPalladium or hydrogen absorber 5.5. RetarderRetarder 6.6. FilleFille www.indiandentalacademy.comwww.indiandentalacademy.com
  63. 63. CHEMIETRYCHEMIETRY  It is an addition reaction. In this case theIt is an addition reaction. In this case the base polymer is terminated with Vinylbase polymer is terminated with Vinyl group & is cross linked with silane. Thisgroup & is cross linked with silane. This reaction is activated by the platinum salt.reaction is activated by the platinum salt.  There is no by product as long as there isThere is no by product as long as there is proper balance between the Vinyl siloxaneproper balance between the Vinyl siloxane & the silane siloxane. If proper balance is& the silane siloxane. If proper balance is not there hydrogen is produced causingnot there hydrogen is produced causing air bubbles in the stone modelsair bubbles in the stone models.. www.indiandentalacademy.comwww.indiandentalacademy.com
  64. 64. PROPERTIESPROPERTIES 1.1. Working timeWorking time :-:- it is 3.1 min at 23degreeit is 3.1 min at 23degree it is 1.8min at 37degreeit is 1.8min at 37degree 2.2. Setting timeSetting time :-:- it is 8.9 min at 23degreeit is 8.9 min at 23degree it is 5.9min at 37degreeit is 5.9min at 37degree 3.3. Reproduce excellent surface detailsReproduce excellent surface details 4.4. Dimensional stabilityDimensional stability :-:- Best in all elastomers. Low curingBest in all elastomers. Low curing shrinkage with 0.17% & lowest permanentshrinkage with 0.17% & lowest permanent deformation of 0.05 – 0.3%deformation of 0.05 – 0.3% 5.5. Tear strengthTear strength :-:- It is 1500 – 4300 N/mIt is 1500 – 4300 N/m www.indiandentalacademy.comwww.indiandentalacademy.com
  65. 65. PROPERTIESPROPERTIES 6. Hydrophobic6. Hydrophobic 7. Low flexibility & is harder than polysulfide.7. Low flexibility & is harder than polysulfide. 8.8. Coefficient of thermal expansionCoefficient of thermal expansion :-:- 190190x10-6 degree-1x10-6 degree-1 9. Weight loss of material at 24hrs is 0.05%9. Weight loss of material at 24hrs is 0.05% 10. Shelf life is 1 – 2 year10. Shelf life is 1 – 2 year 11.11. BiocompatibilityBiocompatibility :-:- No allergic response to this material.No allergic response to this material. www.indiandentalacademy.comwww.indiandentalacademy.com
  66. 66. POLYETHER IMPRESSIONPOLYETHER IMPRESSION MATERIALMATERIAL  This was introduced in Germany in late 1960’s. it hasThis was introduced in Germany in late 1960’s. it has good mechanical properties & dimensional stability.good mechanical properties & dimensional stability.  MODE OF SUPPLYMODE OF SUPPLY It is available as a base & accelerator in paste. It isIt is available as a base & accelerator in paste. It is available in three viscosities :-available in three viscosities :- 1.1. Light bodiedLight bodied 2.2. Medium bodiedMedium bodied 3.3. Heavy bodiedHeavy bodied  COMMERSIAL NAMECOMMERSIAL NAME 1.1. ImpregumImpregum 2.2. RamitecRamitec www.indiandentalacademy.comwww.indiandentalacademy.com
  67. 67. COMPOSITIONCOMPOSITION  BASEBASE 1.1. Polyether polymerPolyether polymer :-:- 2.2. Inert fillerInert filler :-:- Colloidal silica is usedColloidal silica is used 3.3. plasticizerplasticizer :-:- Phthalate or GlycoletherPhthalate or Glycolether usedused  ACCELERATOR orACCELERATOR or CATALYST PASTECATALYST PASTE 1.1. Aromatic sulfonate esterAromatic sulfonate ester 2.2. Inert fillerInert filler :-:- Silica is usedSilica is used 3.3. PlasticizerPlasticizer :-:- Pathalate or GlycoeatherPathalate or Glycoeather www.indiandentalacademy.comwww.indiandentalacademy.com
  68. 68. CHEMISTRYCHEMISTRY  It is cured by the reaction between aziridineIt is cured by the reaction between aziridine rings which are at the end of branched polyetherrings which are at the end of branched polyether molecule. The main chain is a copolymer ofmolecule. The main chain is a copolymer of ethylene oxide & tetrahydrofuran. Cross linkingethylene oxide & tetrahydrofuran. Cross linking is brought about the aromatic sulfonate ester viais brought about the aromatic sulfonate ester via imine end group. The reaction is exothermic.imine end group. The reaction is exothermic. POLYEATHERPOLYEATHER++ SULFONIC ESTERSULFONIC ESTER →→ CROSS LINKED RUBBERCROSS LINKED RUBBER www.indiandentalacademy.comwww.indiandentalacademy.com
  69. 69. PROPERTIESPROPERTIES 1.1. Working timeWorking time :-:- it is 3.3 min at 23 degreeit is 3.3 min at 23 degree it is 2.3 min at 37 degreeit is 2.3 min at 37 degree 2.2. Setting timeSetting time :-:- it is 9 min at 23 degreeit is 9 min at 23 degree it is 8.3 min at 37 degreeit is 8.3 min at 37 degree 3.3. Bitter taste with no smell.Bitter taste with no smell. 4.4. Dimensional stabilityDimensional stability :-:- It is very good. Curing shrinkage is low withIt is very good. Curing shrinkage is low with 0.24%. The permanent deformation is low with0.24%. The permanent deformation is low with 1 – 2%1 – 2% 5.5. It is extremely stiff & flexibility is 3%.It is extremely stiff & flexibility is 3%. www.indiandentalacademy.comwww.indiandentalacademy.com
  70. 70. PROPERTIESPROPERTIES 6.6. Tear strengthTear strength :-:- 1800 – 4800N/m1800 – 4800N/m 7. Hydrophilic7. Hydrophilic 8.8. BiocompatibilityBiocompatibility :-:- the Sulfonic eater component may causethe Sulfonic eater component may cause skin allergy.skin allergy. 9.9. Coefficient of thermal expansionCoefficient of thermal expansion :-:- 300300x10degree-1x10degree-1 10. Shelf life is 20 -24months.10. Shelf life is 20 -24months. www.indiandentalacademy.comwww.indiandentalacademy.com
  71. 71. LIGHT ACTIVATED IMPRESSIONLIGHT ACTIVATED IMPRESSION MATERIALMATERIAL  With the increase used of light activated restorativeWith the increase used of light activated restorative materials, light activated impression materials werematerials, light activated impression materials were developed during the late1980’s. The advantages ofdeveloped during the late1980’s. The advantages of such a material is there unlimited working time,such a material is there unlimited working time, eliminating one of the primary challenge in clinicaleliminating one of the primary challenge in clinical impression making for complex multi – abutment fixedimpression making for complex multi – abutment fixed partial dentures. Its used chemistry is similar that usedpartial dentures. Its used chemistry is similar that used by light cured composite.by light cured composite.  Available in two viscosities :-Available in two viscosities :- 1.1. Lighted bodiedLighted bodied 2.2. Heavy bodiedHeavy bodied www.indiandentalacademy.comwww.indiandentalacademy.com
  72. 72. COMPOSITIONCOMPOSITION 1.1. Polyether urethanePolyether urethane dimethacrylatedimethacrylate 2.2. Photo initiatorPhoto initiator 3.3. Photo acceleratorPhoto accelerator 4.4. Silica dioxide filler:- 40 – 60%Silica dioxide filler:- 40 – 60% www.indiandentalacademy.comwww.indiandentalacademy.com
  73. 73. PROPERTIESPROPERTIES 1.1. This material have a very long workingThis material have a very long working time but short setting time. Blue light istime but short setting time. Blue light is used for curing.used for curing. 2.2. Tear strengthTear strength :-:- 6000 – 7500 gm/cm6000 – 7500 gm/cm 3.3. The dimensional stability, flow, detailThe dimensional stability, flow, detail reproduction, permanent deformation,reproduction, permanent deformation, compatibility with cast is similar tocompatibility with cast is similar to addition silicone.addition silicone. www.indiandentalacademy.comwww.indiandentalacademy.com
  74. 74. MANIPULATION OFMANIPULATION OF ELASTOMERIC MATERIALELASTOMERIC MATERIAL  SPATULATIONSPATULATION :-:- Impression materials dispend in tubes requireImpression materials dispend in tubes require spatulation on disposable pads. Dispending on thespatulation on disposable pads. Dispending on the specific material, one or both paste may adherespecific material, one or both paste may adhere tenaciously to the spatula. Wiping the spatula clean &tenaciously to the spatula. Wiping the spatula clean & continuing to mix will minimizing the presence of streakscontinuing to mix will minimizing the presence of streaks of unmixed base or catalyst.of unmixed base or catalyst.  AUTOMIXING TECHNIQUEAUTOMIXING TECHNIQUE :-:- Most silicone & polyether impression materialMost silicone & polyether impression material are available in auto mix cartridge. Auto mix has beenare available in auto mix cartridge. Auto mix has been shown to result in few voids. Direct syringe tips that fitsshown to result in few voids. Direct syringe tips that fits into the auto mixing tube are available. Access isinto the auto mixing tube are available. Access is occasionally a problem.occasionally a problem.  MIXING MACHINESMIXING MACHINES :-:- With in the last few years, a mixing machinesWith in the last few years, a mixing machines was introduced for use with polyether impressionwas introduced for use with polyether impression materials. Among its advantages is reduction of voids inmaterials. Among its advantages is reduction of voids in the resulting mix & tray. Rather than rely on smallthe resulting mix & tray. Rather than rely on small cartridge, larger bulk package of impression pate arecartridge, larger bulk package of impression pate are available.available. www.indiandentalacademy.comwww.indiandentalacademy.com
  75. 75. DISINFECTION OFDISINFECTION OF ELASTOMERIC MATERIALSELASTOMERIC MATERIALS 1.1. POLYSULFIED IMPRESSION MATERIALPOLYSULFIED IMPRESSION MATERIAL :-:- Glutaraldehydes, chlorine compounds,Glutaraldehydes, chlorine compounds, iodophor, phenolics are the recommended disinfectant.iodophor, phenolics are the recommended disinfectant. Impression should be immersed in this disinfectant forImpression should be immersed in this disinfectant for 30 sec.30 sec. 2.2. POLYETHER IMPRESSION MATERIALSPOLYETHER IMPRESSION MATERIALS :-:- Chlorine compounds or iodophors areChlorine compounds or iodophors are the recommended disinfectant. Immerse thethe recommended disinfectant. Immerse the impression in to disinfectant, not more than for 10 min.impression in to disinfectant, not more than for 10 min. 3.3. SILICONE IMPRESSION MATERIALSILICONE IMPRESSION MATERIAL :-:- Glutaraldehydes, chlorine compounds, iodophors,Glutaraldehydes, chlorine compounds, iodophors, phenolic are the recommended disinfectant forphenolic are the recommended disinfectant for Addition & Condensation silicon impression material.Addition & Condensation silicon impression material. Impression should be immersed in the disinfectant forImpression should be immersed in the disinfectant for 30 min.30 min. www.indiandentalacademy.comwww.indiandentalacademy.com
  76. 76. COMMON FAILURE THET OCCUR WITH USECOMMON FAILURE THET OCCUR WITH USE OF ELASTOMERIC IMPRESSION MATERIALOF ELASTOMERIC IMPRESSION MATERIAL 1.1. Rough or uneven surface on impressionRough or uneven surface on impression:- it occur due to:- it occur due to  Incomplete polymerizationIncomplete polymerization  Improper ratioImproper ratio  Presence of oil or other organic material on teethPresence of oil or other organic material on teeth  Rapid polymerizationRapid polymerization 2.2. BubblesBubbles :- it occur due to:- it occur due to  Too rapid polymerizationToo rapid polymerization  Air incorporated during mixingAir incorporated during mixing 3.3. Irregular shaped voidsIrregular shaped voids :- it occur due to:- it occur due to  Presence of moisture or debris on the surface of teethPresence of moisture or debris on the surface of teeth 4.4. Rough & chalkyRough & chalky:- it is due to:- it is due to  Inadequate cleaning of impressionInadequate cleaning of impression  Excess water left on surface of the impressionExcess water left on surface of the impression  Excess wetting agent on impressionExcess wetting agent on impression  Premature removal of castPremature removal of cast 5.5. DistortionDistortion :- it is due to:- it is due to  Lack of adhesion on trayLack of adhesion on tray  Lack of mechanical retention for material where is in effectedLack of mechanical retention for material where is in effected  ExcessiveExcessive bulk of materialbulk of material  Movement of tray during polymerizationMovement of tray during polymerization  Premature or improper removal of impressionPremature or improper removal of impressionwww.indiandentalacademy.comwww.indiandentalacademy.com
  77. 77. ADVANTAGES & DISADVANTAGESADVANTAGES & DISADVANTAGES MATERIALSMATERIALS ADVANTAGESADVANTAGES DISADVANTAGESDISADVANTAGES 1. Polysulfide1. Polysulfide 1.Long working time1.Long working time 2.High tear resistance2.High tear resistance 3.Margins easily seen3.Margins easily seen 4.Comparativey4.Comparativey 5.Modest cost5.Modest cost 1.Poor patient1.Poor patient acceptanceacceptance 2.Long setting time2.Long setting time 3.Require custom tray3.Require custom tray 4.Hydrophobic4.Hydrophobic 5.Pour with in hr.5.Pour with in hr. 2. Condensation2. Condensation siliconesilicone 1.Short setting time1.Short setting time 2. Easy to use2. Easy to use 1.1. HighHigh polymerizationpolymerization shrinkageshrinkage 2.2. Low tear strengthLow tear strength 3.3. Low dimensionalLow dimensional stabilitystability 4.4. More difficult toMore difficult to pourpourwww.indiandentalacademy.comwww.indiandentalacademy.com
  78. 78. ADVATAGES & DISADVANTAGESADVATAGES & DISADVANTAGES MATERIALSMATERIALS ADVANTAGESADVANTAGES DISADVANTAGESDISADVANTAGES AdditionAddition siliconesilicone 1.Excellent1.Excellent dimensionaldimensional 2.Short setting time2.Short setting time 3.Auto mixing3.Auto mixing cartridgecartridge 4.Easly seen margin4.Easly seen margin 1.Hydrophobic1.Hydrophobic 2.No flow if sulcus is2.No flow if sulcus is moistmoist 3.Low strength3.Low strength 4.Difficult to pour4.Difficult to pour 5. High cost5. High cost PolyetherPolyether 1.Auto mix1.Auto mix dissensionsdissensions 2. Easily seen margin2. Easily seen margin 3.Good stability3.Good stability 4.High tear strength4.High tear strength 1.Stiff, high modulus1.Stiff, high modulus 2.Bitter taste2.Bitter taste 3.Absorb water3.Absorb water 4.High cost4.High cost www.indiandentalacademy.comwww.indiandentalacademy.com
  79. 79. www.indiandentalacademy.comwww.indiandentalacademy.com
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