overview of impression materials

1. Good morning

2. RECENT ADVANCES INRECENT ADVANCES IN
IMPRESSION MATERIALSIMPRESSION MATERIALS
A. RAM KOTI REDDY
First year post graduate
Dept of Prosthodontics

3. CONTENTS:
 Classification of impression materials.
 Desirable properties.
 Alginate
● composition
● application
●recent advances
 Elastomers
● classification
● recent advances
 Digital imaging
advantages
disadvantages
different avaiable systems

4. IMPRESSION MATERIALS :
 ●Any substances or combination of
substances used for making an impression
or negative reproduction .
 DENTAL IMPRESSION:
●An exact negative replica of the teeth
and its associated oral tissues with
accurate reproduction of all finer detail,
maintaining correct spatial dimensions.

6. DESIRABLE QUALITIES OF
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

7. ●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

8. ALGINATE:
 Elastic ,irreversible
 most frequently used dental material.

9. 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
Coloring and flavouring agent traces For the comfort of patient

10. 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 preliminary impression for
complete dentures and treatment dentures.
 As a duplicating material.

11. 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

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

13. 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.

14. 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

15.  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

16.  Every drop of Personal Krono—20sec

17. 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.

18. 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.

19. 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

20. 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

21. 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.

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

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

24. ELASTOMERIC
IMPRESSION MATERIALS

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

26. 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.

27. COMPOSITION OF POLYSULPHIDE
Base paste
Accelerator paste

28. 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
Cast should be poured immediately.
USED TO RECORD IMPRESSIONS FOR CROWNS,
BRIDGES, INLAYS, ONLAYS AND PARTIAL
DENTURES

29. ADVANTAGES: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

30. COE-FLEX REGULAR BODY LEAD-
FREE 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)

31. 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

32. COMPOSITION OF CONDENSATION SILICONE
Base paste
Accelarator paste

33. SETTING REACTION
 exthothermic .
 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.
 Electroplated

34. 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.

35. 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
disadvantages
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)
6) Slightly expansive.

36.  Products available:-
 Accoe(GC)
 Cuttersil(Heraeus Kulzer) –
 Silene(Bosworth)
 Speedex(Coltene Whaledent)
 Xantopren(Heraeus Kulzer)

37. 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

38. COMPOSITION OF ADDITION SILICONE
Base paste

39. REACTOR/ACCELERATOR PASTE

40. 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.

41. 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

42. PRODUCTS AVAIABLE:
 Impressiv( Cosmedent) –truly hydrophilic
 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)

43. VINYLSILOXANETHER - IDENTIUM
 extremely hydrophilic, highly flowable, provides
excellent resilience.
 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 viscosity
● light viscosity

44. 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

45. FUTAR:
 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

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

48. POLYETHER:POLYETHER:
Composition
 Base paste:
• Polyether prepolymer with terminal ethylene-
imine groups.
• Fillers
• Plasticizers
 Catalyst paste
• Aromatic sulfonic acid ester
• Fillers
• Plasticizers

49. 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
a) Addition polymerization reaction.
b) Less polymerization shrinkage

50. 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)

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

52.  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 .

53. 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

54.  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

55. 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

56. 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

57. 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.


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

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

60.  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
 11.Increased patient satisfaction
 12. Some systems have color scanning, shade
selection, and still photograph image-taking

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

62. 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

63. 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.

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

65. REFERENCES:
 Anusavice,shen,rawls, Arvind shenoy, Phillip’s science
of dental materials. 1st
edition.
 Applied dental materials ,john F. Mc Cabe&Angus
W.G.Walls,8th
edition
 Dental impression materials and techniques by Amit
punj et al
 alginate impression material:From then till now by
Dr.Gurleen kaur et al.

66. Thank you