Impression Materials

1. IMPRESSION
MATERIALS AND
RECENT ADVANCES
Presented By:
Dr Muskan Agarwal

2. CONTENTS:
Definition
Classification of impression materials.
Desirable properties.
Non Elastic/Rigid Impression Materials
 Impression Plaster
 Zinc oxide Eugenol Paste
 Impression Compound
Elastic Impression Material
 Agar
 Alginate
 Elastomers
Digital imaging

3. DENTAL IMPRESSION
A dental impression is a negative imprint of hard (teeth)
and soft tissues in the mouth from which a positive
reproduction (cast or model) can be formed.
IMPRESSION MATERIALS
•Impression material is of liquid or semi-solid nature
when first mixed and placed in the mouth. It then sets to
become an elastic solid (usually takes a few minutes
depending upon the material), leaving an imprint of
person's dentition and surrounding structures of oral
cavity.

5. DESIRABLE QUALITIES O F
IMPRESSION MATERIALS:
Biocompatibility:
 nonirritant,non allergic
 acceptable taste and odour
 should not absorb or dissolve in oral
fluid
Rheological Properties
 low viscosity
 viscosity should increase quickly
 pseudoplastic nature
Mechanical properties:
 high elasticity and complete elastic
recovery

6.  Adequate compressive strength
 high tear strength
 high flexibility
Thermal properties:
 low softening temperatures
 high thermal conductivity
Physical properties
 good dimensional stability
 reproduction of details
Others
 economical
 easy to use

11. Theories of Setting
1. Colloidal Theory
2. Hydration Theory
3. Dissolution Theory( Crystalline theory)

65. ALGINATE:
• Elastic
• Irreversible hydrocolloid
• Most frequently used dental material.

66. COMPOSITION OF ALGINATE:
Ingredients % by wt. Functions
Sodium or Potassium or
Triethanolamine alginate
15% Dissolve in water
Calcium sulphate ( Reactor ) 16% Reacts with soluble alginates
and form insoluble calcium
alginate
Zinc Oxide 4% Act as a filler particle
Potassium Titanium Fluoride 3% Act as accelerator for the
setting of a stone to be poured
in impression to ensure hard,
dense surface of a cast.
Diatomaceous Earth 60% Also act as a filler ,
provide strength and
stiffness
Sodium Phosphate ( Retarder ) 2% Reacts with calcium
sulphate there by retard
the setting of impression

67. APPLICATION :
• It is used for impression making
- when there are undercuts
- in mouth with excessive flow of saliva
- for partial dentures with clasp
• For making a
preliminaryimpression for complete
dentures and treatment dentures.
• As a duplicating material.

68. DRAWBACKS WITH
ALGINATE:
• Poor dimensional stability (imbibition or
dessication is a problem).
• Low tear strength .
• Silica dust in the form diaomaceous earth.
• Poor adhesive with tray

69. ADVANCES IN ALGINATE
IMPRESSION :
• Extended-pour alginate
• Tray adhesive for alginate
• High viscosity alginate
• Colour changing alginate
• Two paste alginate form
• Infection free alginate

70. EXTENDED -POUR
ALGINATES
Extended pour alginate is designed for use with
alginate impression material which enables to
delay pouring up impression under specified
storage conditions.
MILLENIUM ALGIN is considered an alginate of
new generation alginate.

71. MILLENIUM :
• Class A type 1 alginate
• Tixotropic
• Extra-fast in-mouth minimum setting time 30 sec
• High accuracy: 15 micron
• Long dimensional stability (168 hours)
• Dust free
• 5 years of expiry date

72. Manufactured by LASCOD(Italy)
STORING:
The impression must be stored in a sealed plastic
bag (Safe-Lock Bags by Lascod) without adding
anything else. Do not leave the impression in open
air or immersed in water.
MILLENIUM working time can be extended when
required with Personal Krono liquid.
The liquid does not change
MILLENIUM physical properties

73. 𝗈 Every drop of Personal Krono—20sec

74. TRAY ADHESIVE FOR ALGINATE
liquid and spray containing polymide or diethylenetriamine
polymer, ester gum and rosin in isopropyl alcohol or a
combination of isopropyl alcohol with ethyl acetate has
been introduced.

75. ACCUDENT XD TRAY
ADHESIVE:
New AccuDent XD Impression System creates
impressions with dimensional accuracy and
freedom from air bubbles and voids making it
possible to create visibly better primary stone or
virtual models.

76. DUST FREE ALGINATE:
Sepiolite ,a natural mineral fiber containing
magnesium silicate about 20microns was added
to alginate as a substitute when added traps
the alginate partiles thus reducing dust
generation

77. COLOUR CHANGING ALGINATE:
A combination of inorganic and organic(cresol red ,
naptholpthalein) along pH indicator has been
incorparated .
In such cases,the intial color of the alginate soon after
mixing is a combination of pigment and Ph indicator where
as the color of alginate after setting is the color due to
pigment alone

78. TWO FORM PASTE ALGINATE:
• Quite convenient to mix.
• Base paste contains a mix of soluble alginate,
water and fillers.
• The reactor or catalyst paste contains calcium salt
mixed with a viscous liquid that is non reactive
towards calcium salt such as liquid paraffin.
• A pH stabilizing agent such as magnesium
hydroxide is also added.

79. INFECTION FREE ALGINATE :
quaternary
bisquanidine
ammonium
compounds,
compounds,
chlorhexidine,
didecyldimethyl ammonium chloride without
altering its properties.

80. COMMERCIAL
BRANDS:
Coe Alginate (GC America)
Integra (Kerr)
Jeltrate (Dentsply Caulk)
Zelgan (DPI)

81. E L A S T O M E R I C I M P R E S S I O N
M A T E R I A L S
Elastomers comprises a group of synthetic
polymer based impression material that are
chemically crosslinked when set

82. Advantages of elastomeric
impression materials over
the hydrocolloid
• higher tear strength
• dimensionally stable on storage.
• Most of elastomers can be electroplated

83. ELASTOMERS:
Elastomers are of 3 types
1)POLYSULPHIDE
2)SILICONES
a)Addition Silicones
b)Condensation Silicones.
3)POLYETHERS
a)Light activated polyethers
b)Chemically activated polyethers.

84. COMPOSITION OF POLYSULPHIDE
Base paste
Accelerator paste

85. PROPERTIES OF POLYSULFIDE
1.Available in variety of viscosities (Light, Regular,
Heavy, Putty)
2) Working time = 3-6 min
3) Setting time = 10-20 min.
4) Highly flexible of all the elastomers.
5) Elastic recovery improves with time .
6) High tear strength.
7) Not dimensionally stable
8) Cast should be poured immediately.
USED TO RECORD IMPRESSIONS FOR CROWNS,
BRIDGES, INLAYS, ONLAYS AND PARTIAL
DENTURES

86. ADVANTAGES:
 Good wettability
 Good surface detail
 High tear strength
 Long working time
DISADVANTAGES:
 High permanent deformation
 Staining of clothes
 Unpleasant rubbery smell
 Can only be used in a special tray
 Must pour within 1 hour

87. F R E E POLYSULFIDE IMPRESSION
MATERIAL
lead-free, all-purpose rubber base impression
material for inlays, crowns, bridges, full and
partial dentures, rebasing and relining.
Other commerical brands:
Permlastic (Lead dioxide system)
Omniflex (Copper hydroxide system)

88. CONDENSATION SILICONE IMPRESSION
MATERIAL
Alternate names:
1) Conventional silicones.
2) Room temperature vulcanizing (RTV) silicones.
USED TO RECORD IMPRESSIONS FOR CROWNS,
BRIDGES, INLAYS, ONLAYS AND COMPLETE
DENTURES

89. COMPOSITION OF CONDENSATION
SILICONE
Base paste
Accelarator paste

90. SETTING
REACTION
• Exthotheric .
• Cross-linking occurs between the siloxane polymer and
the alkyl silicate in the presence of the activator with the
release of ethyl alcohol as reaction by-product.
• dimensional changes→evapariation of
alcohol+polymeriazation shrinkage
• Alcohol could cause air bubbles in the stone cast.

91. PROPERTIES OF CONDENSATION SILICONE
1)Available in all 4 consistencies
2) Flow after 1 hour = 0.09%
3) Mixing time = 1 min
4) Working time =3 min
5) Setting time = 6-10 min
6) Good tear strength.
7)Flexibility is less than Polysulphides.
8)Dimensionally not stable:
Due to
a) Polymerization shrinkage.
b) Incomplete elastic recovery.
c)Thermal contraction on removal from
mouth to room temperature.

92. Advantages
1)Adequate working time & setting time.
2) Clean & pleasant odour.
3) No staining.
4) Adequate tear strength.
5) Better elastic properties.
6)Can be electroplated with silver and
copper .
Dsadvantages
1) Lower flexibility than polysulphides
2)Poor dimensional stability due to release of by
products.
3) Less accuracy if poured immediately
4) Hydrophobic nature
5) Poor to adequate shelf life (1- 2 years)

93. Products available:-
• Accoe(GC)
• Cuttersil(Heraeus Kulzer)
• Speedex(Coltene Whaledent)
• Xantopren(Heraeus Kulzer)
• Silene(Bosworth)

94. ADDITION SILICONE IMPRESSION
MATERIAL
Have much better properties than Condensation
silicones.
Alternate names:
1) Poly vinyl siloxane.
2) Vinyl poly siloxane.
Used to record impression FOR CROWNS, BRIDGES,
INLAYS,ONLAYS, PARTIAL AND
COMPLETE DENTURES

95. COMPOSITION OF ADDITION
SILICONE
Base paste

96. REACTOR/ACCELERATOR PASTE

97. PROPERTIES OF ADDITION
SILICONE
1)Available in all 4 consistencies.
2)Various consistencies serve different purpose
E.g. Putty or heavy body is used for primary
impressions.
Regular or light body is used for secondary
impressions.
3) Excellent elastic recovery of 99.93%
4)Tear strength of 3500 gm/cm
5) Mixing time is 35-45 sec
6)Working time = 2-3 min.
7) Setting time = 6-8 min.

98. ADVANTAGES:
 Records highly accurate impression.
 Pleasant to handle.
 Shorter setting time.
 Excellent elastic recovery.
 No elimination of any by products.
 Dimensionally stable.
 Can be electroplated with silver & copper.
 Multiple die pour is possible.
DISADVANTAGES
 More expansive with automatic mixing device.
 Shorter working time.
 May release H2 gas on setting.
 Hydrophobic material.
 Latex glove interfer setting reaction.Vinyl and nitrile
gloves can be used

99. PRODUCTS AVAIABLE:
Impressiv( Cosmedent) –truly hydrophilic
𝗈 Imprint 3 Penta (Putty impression material with
automix)
Aquasil/Reprosil/Hydrosil(Dentsply)
Exaflex/ Examix/Exafast/Hydroflex(GC America)
Express, Imprint/Imprint II(3M ESPE)
Flexitime(Heraeus Kulzer)

100. VINYLSILOXANETHER - IDENTIUM
Extremely hydrophilic, highly flowable, provides
excellent resilience.
y
An accurate impressions in the narrowest crevices and
high definition even in the moist sulcus.
the advantages of polyether materials coupled with
those of A-silicones
Avaiable in
●medium viscosicty
●heavy viscosit
● light viscosity

101. EXAFLEX
VPS IMPRESSION MATERIAL:
• EXAFLEX Vinyl Polysiloxane (VPS) impression
materials produce crisp, extraordinarily smooth
and precise impressions for models, crowns, bridges
and dentures.
• Hydrophilic
• Immediate pour
• High tear strength
• Accurate impressions

102. FUTAR:
𝗈 The convenient classic: hard A-silicone with
convenient working time, accurate results and the
utmost comfort.
Extra hard bite registration material ,easy to trim also
with a scalpel

104. POLYETHER IMPRESSION MATERIAL
Commercial names are
Impregum, Remitec, Polyjel , Permadyne etc.
Polyether is available in
3 viscosities (Light, Regular and heavy body)

105. P O LYETHE R:
Composition
Base paste:
• Polyether prepolymer with terminal ethylene-
imine groups.
• Fillers
• Plasticizers
Catalyst paste
•
•
•
Aromatic sulfonic acid ester
Fillers
Plasticizers

106. PROPERTIES OF POLY ETHER :
• Can cause irritation due to presence of
aromatic sulphonic acid catalyst in reactor
paste.
• Elastic recovery =98.9%
• Permanent deformation is 1.1% Flexibility is
low 2%
• Mixing time is 45 sec to 1 minute.
• Working time = 2 minutes.
• Setting time is 3-5 minutes.
• Good dimensional stability due to
• Addition polymerization reaction.
• Less polymerization shrinkage

107. ADVANTAGES
• Accurate and fine details
Good dimensional stability during setting
Good elastic recovery of 98.9%
Compatible with cast & die materials
Pour within one week (if kept dry)
Good wettability (hydrophilic)
•
•
•
•
•

108. DISADVANTAGES
• Stiff (difficult removal from the mouth)
Expensive
Short setting time (3-5 min)
Bitter taste
Absorbs water and changes dimension
•
•
•
•

109. Polyether is hydrophilic and can absorb water in
wet condition (swelling), accordingly
→ Can not be electroplated
→ should be stored in dry environment to
preserve its dimensional accuracy .

110. LIGHT ACTIVATED POLY ETHER
IMPRESSION MATERIAL
Available in 2 viscosities.
● Light body supplied in syringes.
● Heavy body supplied as tubes
COMPOSITION OF LIGHT ACTIVATED POLYETHER

111. PROPERTIES OF LIGHT ACTIVATED
POLY ETHER
• Excellent elasticity.
• It has operator control over the
polymerization.
• Infinite working time.
• Short setting time.
• Low volume shrinkage on setting.
Impression can be stored upto 2 weeks

112. IMPREGUM PENTA SOFT QUICK STEP
HEAVY BODY/LIGHT BODY POLYETHER
IMPRESSION MATERIAL FROM 3M
Pentamix Mixing Unit Cartridge Dispenser
Working time 1min
Setting time 3min

113. POLYJEL NF POLYETHER IMPRESSION
MATERIAL:
Hydrophilic material with excellent memory that will
not distort
• Optimally colored for easy to read detail
• Can delay pour for up to 2 weeks
• Adequate work time with fast set

114. AFFINITY MONOPHASE POLYETHER:
It is ideal for implant impressions, edentulous, and
partial impressions, as well as for the fabrication of
clear aligners in orthodontic treatment.
Enhanced hydrophilicity for excellent performance in
the presence of moisture, especially with subgingival
preparations.
100% cure, which translates to high tear strength and
dimensional stability.
𝗈

115. DIGITAL IMAGING:
Most of modern dentistry is already immersed in digital
dentistry
Computer-aided design (CAD)/computer-aided
manufacturing (CAM) technologies are advancing
rapidly.

116. ADVANTAGES O F INTRAORAL
SCANNING:
 1. Real-time visualization and evaluation
 Easy to correct, manipulate, or recapture images
 Segmental image capture
 Archival digitally, therefore no need to store physical
casts
 No wastage of impression material and therefore
environmentally friendly
 Economical, considering no use of impression trays,
adhesives, or gypsum
 Do not need to disinfect before sending
information to the laboratory

117. 𝗈  8. No damage or wear and tear of the stone casts
 9. Swift communication with the laboratory via
the Internet.
 10. Self-assessment for tooth preparations.
 Increased patient satisfaction
 Some systems have color scanning, shade
selection, and still photograph image-taking

118. DISADVANTAGES OF INTRAORAL
SCANING:
• Initial cost of equipment and software maintenance
fees
• Learning curve can be difficult for some
individuals
• Scan bodies needed for implant systems that are
compatible with the design software
• Difficult to capture occlusion information for
complex prosthodontics treatment.
• Cannot capture subgingival margins if obscured
with blood, saliva, or tissue.
• Unable to accurately capture images of the
edentulous arches
• Scanning patterns need to be followed as per
manufacturer’s recommendations

119. THE FOLLOWING ARE MOST COMMONLY
USED SYSTEM:
1●TRIOS 3:(3 shape)
An innovative wireless intraoral scanner
Easy battery exchange for non-stop scanning
Long-lasting rechargeable batteries
Realistic colors

120. CEREC (SIRONA):
This device is a closed system in that the software is
only compatible with the company”s milling unit and
the image files cannot be exported and used with other
milling system.

121. OTHERS ARE:
Planscan (planmeca,USA)
CS3600(carestream, United states)
Itero element(align technology)

122. REFERENCES:
Anusavice,shen,rawls, Arvind shenoy, Phillip’s science
of dental materials. First south Asian edition.

123. THANK YOU