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Imprints, their classification, method of receipt. Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint. Impression is a negative (reverse) reflection of any organ of the dentomaxillar system: teeth, alveolar sprout or part, palate, nose,

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Types of impressions previous final

Imprints, their classification, method of receipt. Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint


Types of impressions previous final

Impression Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint is a negative (reverse) reflection of any organ of the dentomaxillar system: teeth, alveolar sprout or part, palate, nose,

ear and others like that.

Impression is a negative (reverse) reflection of hard and soft tissues, placed in the area of dental prosthesis and it’s borders which

Is being taken by means of the special impression materials


Types of impressions previous final

Types of impressions: Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

Previous

Final


Types of impressions previous final

Final impressions: Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

Anatomical

Functional


Types of impressions
Types of Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprintimpressions

Single layer

Double layer

Combined


Types of impressions1
Types of Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprintimpressions

Anatomical (orientation)– take with standard or individual tray in the state of calmness of tissues of prosthetic bed and tissues, which are placed on a border with them.

Functional - take with individual tray by means of the special functional tests, in the case of making of removable constructions of dentures :

compression - in the case of pressing of buffer areas of prosthetic bed, by masticatory pressure or by the hand of doctor;

decompression - in the case of minimum pressure on the tissues of prosthetic bed


Types of impressions previous final

Double layer Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint– an exact reflection of gingival edge is taken by means of impression materials of the same group (previous layer + correction layer)

Combined– is taken by means of impression materials of different groups (previous layer + correction layer)

Occlusal–for taking impression in position of central occlusion


Impression trays
Impression trays Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

Standard:made factory

- On maxillae different sizes

- On mandible different sizes

Individual:made in dental laboratory

By material:

plastic

metallic

waxen

Presence of retentin points

perforated

unperforated


Impression trays for taking impression at the same time
Impression trays for taking impression at the same time Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint


Types of impressions previous final

Placing of impression tray in oral cavity Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint


Types of impressions previous final

Impression of maxillae Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint


Types of impressions previous final

Double layer impression Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint


Impression materials
Impression Materials Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Non-elastic

  • Elastic

    • Aqueous hydrocolloids

      • Agar

      • Alginate

    • Non-aqueous elastomers

      • Polysulfide

      • Silicones

        • Condensation

        • Addition

      • Polyether


Indications
Indications Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Diagnostic casts

    • preliminary

    • opposing

  • Indirect reconstruction

    • fixed

    • removable

  • Bite registration


Elastomeric impression materials
Elastomeric Impression Materials Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Viscoelastic

    • physical properties vary

      • rate of loading

  • Rapidly remove

    • decreases permanent deformation

      • chains recoil from a recoverable distance

    • increases tear strength


Types of impressions previous final

Plaster Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

Compound

Waxes

ZnO - Eugenol

Polysulfide

Silicones

Polyether

Non-elastic

Impression Materials

Agar (reversible)

Aqueous Hydrocolloids

Alginate (irreversible)

Elastic

Condensation

Non-aqueous Elastomers

Addition


Aqueous hydrocolloids
Aqueous Hydrocolloids Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Colloidal suspensions

    • chains align to form fibrils

    • traps water in interstices

  • Two forms

    • sol

      • viscous liquid

    • gel

      • elastic solid

  • Placed intra-orally as sol

    • converts to gel

      • thermal or chemical process


Aqueous hydrocolloids1
Aqueous Hydrocolloids Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Semi-permeable membranes

    • poor dimensional stability

  • Evaporation

  • Syneresis

    • fibril cross linking continues

      • contracts with time

      • exudes water

  • Imbibition

    • water absorption

      • swells


Types of impressions previous final

Agar (reversible) Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

Aqueous Hydrocolloids

Alginate (irreversible)

Elastic

Polysulfide

Condensation

Non-aqueous Elastomers

Silicones

Addition

Polyether


Reversible hydrocolloid agar
Reversible Hydrocolloid Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint(Agar)

  • Indications

    • crown and bridge

      • high accuracy

  • Example

    • Slate Hydrocolloid (Van R)


Composition

Agar Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

complex polysaccharide

seaweed

gelling agent

Borax

strength

Potassium sulfate

improves gypsum surface

Water (85%)

cool to 43ºC

agar hydrocolloid (hot) agar hydrocolloid (cold)

(sol)(gel)

heat to 100ºC

Composition


Manipulation
Manipulation Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Gel in tubes

    • syringe and tray material


Manipulation1
Manipulation Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • 3-chamber conditioning unit

    • (1) liquefy at 100°C for 10 minutes

      • converts gel to sol

    • (2) store at 65°C

    • place in tray

    • (3) temper at 46°C for 3 minutes

    • seat tray

    • cool with water at 13°C for 3 minutes

      • converts sol to gel


Advantages
Advantages Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Dimensionally accurate

  • Hydrophilic

    • displaces moisture, blood, fluids

  • Inexpensive

    • after initial equipment

  • No custom tray or adhesives

  • Pleasant flavor

  • No mixing required


Disadvantages
Disadvantages Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Initial expense

    • special equipment

  • Material must be prepared in advanced

  • Tears easily

  • Dimensionally unstable

    • Must be poured immediately

    • Can only be used for a single cast

  • Difficult to disinfect


Types of impressions previous final

Agar (reversible) Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

Aqueous Hydrocolloids

Alginate (irreversible)

Elastic

Polysulfide

Condensation

Non-aqueous Elastomers

Silicones

Addition

Polyether


Irreversible hydrocolloid alginate
Irreversible Hydrocolloid (Alginate) Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Most widely used impression material

  • Indications

    • study models

    • removable fixed partial dentures

      • framework

  • Examples

    • Jeltrate (Dentsply/Caulk)

    • Coe Alginate (GC America)


Composition1

Sodium alginate Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

salt of alginic acid

mucous extraction of seaweed (algae)

Calcium sulfate

reactor

Sodium phosphate

retarder

Filler

Potassium fluoride

improves gypsum surface

2 Na3PO4 + 3 CaSO4 Ca3(PO4)2 + 3 Na2SO4

H2O

Na alginate + CaSO4 Ca alginate + Na2SO4

(powder) (gel)

Composition


Manipulation2
Manipulation Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Weigh powder

  • Powder added to water

    • rubber bowl

    • vacuum mixer

  • Mixed for 45 sec to 1 min

  • Place tray

  • Remove 2 to 3 minutes

    • after gelation (loss of tackiness)


Advantages1
Advantages Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Inexpensive

  • Easy to use

  • Hydrophilic

    • displace moisture, blood, fluids

  • Stock trays


Disadvantages1
Disadvantages Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Tears easily

  • Dimensionally unstable

    • immediate pour

    • single cast

  • Lower detail reproduction

    • unacceptable for fixed pros

  • High permanent deformation

  • Difficult to disinfect


Non aqueous elastomers
Non-Aqueous Elastomers Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Synthetic rubbers

    • mimic natural rubber

      • scarce during World War II

  • Large polymers

    • some chain lengthening

    • primarily cross-linking

  • Viscosity classes

    • low, medium, high, putty

    • monophasic


Types of impressions previous final

Agar (reversible) Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

Aqueous Hydrocolloids

Alginate (irreversible)

Elastic

Polysulfide

Condensation

Non-aqueous Elastomers

Silicones

Addition

Polyether


Polysulfide
Polysulfide Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • First dental elastomers

  • Indications

    • complete denture

    • removable fixed partial denture

      • tissue

    • crown and bridge

  • Examples

    • Permlastic (Kerr)

    • Omni-Flex (GC America)


Composition2
Composition Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Base

    • polysulfide polymers

    • fillers

    • plasticizers

  • Catalyst

    • lead dioxide (or copper)

    • fillers

  • By-product

    • water


Polysulfide reaction

O Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

O

=

=

mercaptan + lead dioxide polysulfide rubber + lead oxide + water

Pb

Pb

=

=

O

O

Polysulfide Reaction

--SH

HS---------------------SH

HS--

-S-S---------------S-S-

S

S

+ 3PbO + H2O

H

S

O = Pb = O

H

S


Manipulation3
Manipulation Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Adhesive to tray

  • Uniform layer

    • custom tray

  • Equal lengths of pastes

  • Mix thoroughly

    • within one minute

  • Setting time 8 – 12 minutes

  • Pour within 1 hour


Advantages2
Advantages Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Lower cost

    • compared to silicones and polyethers

  • Long working time

  • High tear strength

  • High flexibility

  • Good detail reproduction


Disadvantages2
Disadvantages Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Poor dimensional stability

    • water by-product

    • pour within one hour

    • single pour

  • Custom trays

  • Messy

    • paste-paste mix

    • bad odor

    • may stain clothing

  • Long setting time


Types of impressions previous final

Agar (reversible) Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

Aqueous Hydrocolloids

Alginate (irreversible)

Elastic

Polysulfide

Condensation

Non-aqueous Elastomers

Silicones

Addition

Polyether


Condensation silicone
Condensation Silicone Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Indications

    • complete dentures

    • crown and bridge

  • Examples

    • Speedex (Coltene/Whaledent)

    • Primasil (TISS Dental)


Composition3
Composition Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Base

    • poly(dimethylsiloxane)

    • tetraethylorthosilicate

    • filler

  • Catalyst

    • metal organic ester

  • By-product

    • ethyl alcohol

Phillip’s 1996


Types of impressions previous final

C Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint2H5O

OC2H5

Si

C2H5O

OC2H5

CH3

CH3

CH3

CH3

CH3

CH3

CH3

CH3

HO – Si – O – Si - O - H

HO – Si – O – Si - O -

HO – Si – O – Si - O -

HO – Si – O – Si - O - H

CH3

CH3

CH3

CH3

CH3

CH3

CH3

CH3

n

n

n

n

OC2H5

+ 2C2H5OH

Si

OC2H5

CondensationSilicone Reaction

metal organic ester

ethanol


Manipulation4
Manipulation Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Mix thoroughly

    • paste - paste

    • paste - liquid

  • Putty-wash technique

    • reduces effect of polymerization shrinkage

    • stock tray

      • putty placed

      • thin plastic sheet spacer

      • preliminary impression

        • intraoral custom tray

      • inject wash material


Advantages3
Advantages Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Better elastic properties

  • Clean, pleasant

  • Stock tray

    • putty-wash

  • Good working and setting time


Disadvantages3
Disadvantages Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Poor dimensional stability

    • high shrinkage

      • polymerization

      • evaporation of ethanol

    • pour immediately

      • within 30 minutes

  • Hydrophobic

    • poor wettability


Types of impressions previous final

Agar (reversible) Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

Aqueous Hydrocolloids

Alginate (irreversible)

Elastic

Polysulfide

Condensation

Non-aqueous Elastomers

Silicones

Addition

Polyether


Addition silicones
Addition Silicones Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • AKA: Vinyl polysiloxane

  • Indications

    • crown and bridge

    • denture

    • bite registration

  • Examples

    • Extrude (Kerr)

    • Express (3M/ESPE)

    • Aquasil (Dentsply Caulk)

    • Genie (Sultan Chemists)

    • Virtual (Ivoclar Vivadent)


Composition4
Composition Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Improvement over condensation silicones

    • no by-product

  • First paste

    • vinyl poly(dimethylsiloxane)prepolymer

  • Second paste

    • siloxane prepolymer

  • Catalyst

    • chloroplatinic acid

Phillip’s 1996


Types of impressions previous final

O Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

O

- Si – CH3

H - Si – CH3

CH3

CH3

O

O

CH = CH2 – Si – O ---

CH2 - CH2 – Si – O ---

CH3 - Si - H

CH3 - Si -

CH3

CH3

O

O

CH3

CH3

---O – Si – CH = CH2

---O – Si – CH2 - CH2

CH3

CH3

Addition Silicone Reaction

Chloroplatinic Acid Catalyst


Manipulation5
Manipulation Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Adhesive to tray

  • Double mix

    • custom tray

      • heavy-body

    • light-body to prep

  • Putty-wash

    • stock tray


Advantages4
Advantages Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Highly accurate

  • High dimensional stability

    • pour up to one week

  • Stock or custom trays

  • Multiple casts

  • Easy to mix

  • Pleasant odor


Disadvantages4
Disadvantages Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Expensive

  • Sulfur inhibits set

    • latex gloves

    • ferric and Al sulfateretraction solution

  • Pumice teeth beforeimpressing

  • Short working time

  • Lower tear strength

  • Possible hydrogen gas release

    • bubbles on die

    • palladium added to absorb


Addition silicones1
Addition Silicones Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Surfactants added

    • reduce contact angle

    • improved

      • castability

        • gypsum

      • wettability

        • still need dry field clinically


Types of impressions previous final

Agar (reversible) Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

Aqueous Hydrocolloids

Alginate (irreversible)

Elastic

Polysulfide

Condensation

Non-aqueous Elastomers

Silicones

Addition

Polyether


Polyether
Polyether Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Indications

    • crown and bridge

    • bite registration

  • Examples

    • Impregum F (3M/ESPE)

    • Permadyne (3M/ESPE)

    • Pentamix (3M/ESPE)

    • P2 (Heraeus Kulzer)

    • Polygel (Dentsply Caulk)


Composition5
Composition Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Base

    • difunctional epimine-terminated prepolymer

    • fillers

    • plasticizers

  • Catalyst

    • aromatic sulfonic acid ester

    • fillers

  • Cationic polymerization

    • ring opening and chain extension


Polyether reaction

CH Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint3 – CH – CH2 – CO2 – CH – (CH2)n – O – CH – (CH2)n – CO2 –CH2 – CH –CH3

R

R

m

+ R+

N

N

N

N

N

H2C

H2C

H2C

H2C

H2C

CH2

CH2

CH2

CH2

CH2

SO3-

R – +

R – N – CH2 – CH2 – +

+

Polyether Reaction

base

catalyst

ring opening


Manipulation6
Manipulation Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Adhesive to tray

    • stock or custom tray

      • very stiff

  • Paste-paste mix

  • Auto-mixing

    • hand-held

      • low viscosity

    • mechanical dispenser

      • high viscosity


Advantages5
Advantages Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Highly accurate

  • Good dimensional stability

  • Stock or dual-arch trays

  • Good surface detail

  • Pour within one week

    • kept dry

  • Multiple casts

  • Good wettability


Disadvantages5
Disadvantages Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Expensive

  • Short working time

  • Rigid

    • difficult to remove from undercuts

  • Bitter taste

  • Low tear strength

  • Absorbs water

    • changes dimension


Impression material usage civilian general dentists
Impression Material Usage* Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprintCivilian General Dentists

  • Crown & Bridge

    • vinylpolysiloxane 81%

    • alginate 38%

    • polyether 28%

  • Inlays and Onlays

    • vinylpolysiloxane 71%

    • polyether 22%

    • alginate 20%


Impression material usage civilian general dentists1
Impression Material Usage* Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprintCivilian General Dentists

  • Complete dentures

    • alginate 58%

    • vinylpolysiloxane 55%

    • polyether 27%

  • Partial dentures

    • alginate 78%

    • vinylpolysiloxane 43%

    • polyether 15%


Handling properties
Handling Properties Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint


Handling properties1
Handling Properties Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint


Properties
Properties Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint


Comparison of properties
Comparison of Properties Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Working time

    • longest to shortest

      • agar > polysulfide > silicones > alginate = polyether

  • Setting time

    • shortest to longest

      • alginate < polyether < agar < silicones < polysulfide


Comparison of properties1
Comparison of Properties Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Stiffness

    • most to least

      • polyether > addition silicone > condensation silicone > polysulfide = hydrocolloids

  • Tear strength

    • greatest to least

      • polysulfide > addition silicone > polyether > condensation silicone >> hydrocolloids


Comparison of properties2
Comparison of Properties Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Cost

    • lowest to highest

      • alginate < agar = polysulfide <condensation silicone < addition silicone < polyether

  • Dimensional stability

    • best to worst

      • addition silicone > polyether > polysulfide > condensation silicone > hydrocolloid

Phillip’s 1996


Comparison of properties3
Comparison of Properties Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Wettability

    • best to worst

      • hydrocolloids > polyether > hydrophilic addition silicone > polysulfide > hydrophobic addition silicone = condensation silicone

  • Castability

    • best to worst

      • hydrocolloids > hydrophilic addition silicone > polyether > polysulfide > hydrophobic addition silicone = condensation silicone


Regularly used impression materials civilian practitioners
Regularly-Used Impression Materials* Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprintCivilian Practitioners

  • Alginate 88%

  • Polyvinyl Siloxane 85%

  • Polyether 27%

  • Other 6%


Summary
Summary Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Study models

    • Alginate most widely used

      • inexpensive

      • displaces moisture

      • lower detail reproduction

      • dimensionally unstable


Summary1
Summary Classification of materials of imprint. Clinical, physical and chemical descriptions of materials for imprint

  • Prosthodontics

    • Addition silicones most popular

      • accurate

      • dimensionally stable

      • user friendly

      • expensive