in prosthodontics

1. Presented by:-
Dr. Richa Sahai
II MDS
Guided by:
Dr. U.M. Radke Dr. N.A. Pande Dr. S Deshmukh
HOD & Guide Professor Reader
Dr. T.K. Mowade Dr. R. Banerjee Dr. A. Chandak
Reader Reader Reader

2. Contents
• Introduction
• Criteria for an ideal impression
• Definitions
• Review of Literature
• Impression making techniques
• Disinfecting impressions
• Summary
• Conclusion
• References

3. Introduction
For a dentist it is very important to select a suitable impression technique
using appropriate materials to get a model as accurate as possible.
Therefore it is important to know the different impression techniques
which will give the maximum benefits within the available materials.

4. • An acceptable impression must be an exact record of all aspects of the
prepared tooth
• The contour of the unprepared tooth structure cervical to the preparation
margin is critical information .
TOOTH RESTORATION INTERFACE

5. • If the impression does not reproduce this critical area where tooth and future
restoration meet, fabricating the restoration with proper contours is not
possible .
PROERLY CONTOURED RESTORATIONS

6. • Particular attention is given to reproducing the lingual surfaces of anterior teeth
because they influence Anterior Guidance .
• Impression must be free of air bubbles, tears, & spots, and other imperfections
that might produce inaccuracies.
FAULTY IMPRESSION
CORRECT
IMPRESSION

7. A negative likeness or copy in reverse of the surface of an object
DEFINITIONS
GPT 9th ed.
IMPRESSION MATERIAL:
Any substance or combination of substances used for making an impression or
negative reproduction
CAST:
A life – size likeness of some desired form. It is formed within or is a material
poured into a matrix or impression of desired form
GPT 9th ed.
GPT 9th ed.

8. • Any moisture will result in voids
• Consequently, saliva flow into the area must be reduced and diverted to
obtain the necessary dry field of operation
• When the preparation margins extend sub-
gingivally, the adjacent gingival tissues must be
displaced laterally to allow access and to provide
adequate thickness of the impression material
GINGIVAL RETRACTION

9. 1. Eames et al - fabricated impression trays providing 2, 4 & 6 mm spacers to
determine the stability & accuracy of various elastomeric impression materials
on a full crown preparation steel die.
• Conclusion - space of 2mm provided the most accurate impressions for all of
the materials tested.
2. Marcinak CF, Draughn (1982) conducted a study on linear dimensional
changes in addition silicone impression materials.
• The results showed that dies produced at 168 hours were as accurate as
those produced at 10minutes.
Review of Literature

10. 3.Nissan J et al (2000) - studied the accuracy of 3 putty wash impression
techniques using the poly vinyl siloxane impression material in a laboratory
model.
1) one step ,putty and wash material used simultaneously
2) two step with 2mm spacer
3) two step with polyethylene spacer.
They concluded that the polyvinyl siloxane two step, 2mm spacer putty wash
impression technique was the most accurate.

11. 4. Johnson GH and Craig RG (1986) conducted a study on three impression
techniques:
• a putty-wash,
• single mix impression and
• a double mix impression.
They concluded that the same accuracy of impression was achieved for all the
techniques when addition silicones were used, where as the putty-wash
technique produced the most accurate dies for the condensation silicone.

12. Stock Tray
• A metal or plastic prefabricated impression tray typically available in various
sizes and used principally for preliminary impressions GPT 9
Advantages Disadvantages
Eliminates time and expense of
fabricating custom tray
Metal stock trays are rigid and are
not susceptible to distortion
More impression material is
required
Metal trays must be sterilized

13. An individualized impression tray made from a cast recovered from a preliminary
impression;
• For PVS - 2 mm thickness of base plate wax
• For more rigid materials, polyether - 3 mm is required to facilitate removal from the
mouth and removal of the replica cast.
Custom tray
Advantages:
Because the trays are used only once,
sterilization is not a problem
A uniform thickness of impression
material is obtained
Disadvantages:
Construction of the custom tray is
time consuming
Monomer allergy

14. Evaluating Set
Impression:
Finish line should be
recorded properly
No tray exposure in
any areas of the
impression, except at
tissue stops
No shiny smooth
areas; (suggest
moisture
contamination)
No voids present;
(suggest mixing
problems or
contamination)

15. TYPES OF IMPRESSIONS
PRELIMINARY IMPRESSION
• Generally made in stock or modified stock trays.
• Made with irreversible hydrocolloid and poured in a type III dental stone
(ADA) to produce to diagnostic cast.
FINAL IMPRESSIONS
• Because a definitive restoration is to be constructed final impression
materials must be accurate dimensionally stable, recovery without distortion,
and compatible with a variety of dental stones.

16. Impression making in Fixed partial dentures

17. Copper Band Technique
Solomon E.G.R: Classification of impression procedures in fixed partial denture construction. JIDA Oct 1975.
I. Individual copper band impression together with an orientation
impression.
a. Copper band low fusing compound impression in plaster orientation.
b. Copper band low fusing compound impression in silicone orientation.
c. Copper band silicone impression, in plaster orientation impression
d. Copper band silicone impression in silicone orientation impression.

18. Technique Of Individual Impression
Take a copper band and adapt it around the tooth.
Cut the end of band with scissor to follow the outline
of the gingival finish line.
Evaluate the fit, band should extend approx 1mm
beyond the finish line.
An orientation hole is made on the facial surface of
tube
Green stick compound is heated, and the softened
mass is placed into the band & filled to one-third of
the tube. 18

19. Band is then placed onto the tooth preparation
Tube should not be pushed too deep & only a part of
occlusal surface should be recorded.
Then remove the band from the tooth and remove
the 0.2 mm of compound from impressed occlusal
surface.
Put 4 to 5 holes above the bottom of the copper tube.
Coat the internal surface with adhesive, and inject the
Elastomeric material into the copper band.
Place the band onto the tooth
After the final set, remove the band from the tooth
and evaluate the impression.
19

20. I. Individual Copper Band Impression Together With An
Orientation Impression
Orientation Impression:-
• The relationship of the individual preparation to each other as well as to the remaining
teeth and dental arch is obtained with an orientation impression .
Indications-
1 ] Single tooth preparation.
2] In case of multiple preparations, when the
impression of one or two preparations have not
been recorded properly.

21. ADVANTAGES DISADVANTAGES
a. Impression compound can be used
effectively for complete crown or simple
inlays.
b. In situations where the margins of the
preparation are below the level of the gingival
tissue.
c. The material can be electroplated easily to
produce copper or silver electro formed dies.
a. A band must be contoured, festooned
and annealed and a separate impression
must be taken of each tooth.
b. The band is often difficult to remove.
c. The copper band usually causes some
trauma to the gingival tissue.
d. A die must be formed of each copper
band impression, then must be seated in an
inter- occlusal registration.

22. A. Copper Band Low Fusing Compound Impression In
Plaster Orientation Impression
• A plaster impression over this secures the correct relation of the preparation
to the remaining teeth and dental arch.
• Advantage of using plaster:- For orientation impression is its rigidity. It holds
the band in place preventing its displacement.
• Disadvantage of using plaster:- Is the production of heat as plaster sets &
unpleasant to the patient, when a plaster impression is recorded.

23. Advantages of this technique:
• Any defect in the preparation can be visualized in the impression can be
corrected.
• Gingival retraction is not necessary.
Disadvantage of this technique:
• The warmth from the plaster impression, may soften the compound.

24. • To avoid the action of heat on low fusing compound copper band impression during
setting of plaster, heavy bodied silicone is used to record the orientation impression .
Disadvantage of this technique-
• Fixation of the band to the elastic silicone impression is inadequate.
• It is possible for the band to get displaced in silicone impression resulting in series
errors.
B. Copper Band Low Fusing Compound Impression In
Silicone Orientation Impression

25. • Impression plaster is used to record orientation impression.
• Heat liberated during setting of plaster has no effect on the silicone
individual copper band impression.
• Indications- when there are unavoidable Undercuts between the
preparations
C. Copper Band Silicone Impression In Plaster
Orientation Impression

26. • All the three consistencies of silicone are used for individual impression
while heavy bodied silicone is used to record orientation impression.
• Fixation of copper band to the orientation impression is made more
effective by selecting long band with toothed edges.
D. Copper Band Silicone Impression In Silicone
Orientation Impression

27. Working & setting time

29. 1.Following gelation of the impression material the tray should be separated quickly
from the teeth to avoid rocking and possible deformation of the fine areas of the
impression.
2.Pour cast immediately & the cast should be separated from the impression after 45
to 60 minutes.
Hydrocolloid Impression technique
Irreversible hydrocolloid (Alginate)

30. • They require the special water cooled impression trays to cool the
agar from a sol to gel.
Reversible hydrocolloid (Agar)

31. Select the correct size of water-cooled
impression tray.
Place stops in the tray to prevent over
seating.
Isolate the prepared teeth & place the
retraction cord.
Fill the tray with material taken from the
storage bath
Fill the syringe with the wash hydrocolloid
material taken from the storage bath.
31
Remove the cord from the sulcus.
Hydrocolloid is injected around the
prepared tooth
Tray is removed from the
tempering bath & seated in
patient’s mouth.
Water – cooling tubes are
connected
The completed impression

32. WET FIELD TECHNIQUE
The motion displaces the syringe material as well as blood and debris throughout the sulcus.
The hydraulic pressure of the viscous tray material forces the fluid syringe material down in to the areas to be
recorded.
Before syringe material gels tray material is seated.
The syringe material is then injected in to the surface to be recorded.
The oral tissues are flooded with warm water.

33. • Reversible hydrocolloid impression material used in a wet field produced stone
dies as accurate as those produced in a dry field.
• The surface quality of the dies produced from hydrocolloid impressions made in a
wet field was indistinguishable from the quality of those made in a dry field.
Stewart, GP, Bagley, RL, Froemling, RA. Evaluation of reversible hydrocolloid impression material in a wet field. J Prosthet
Dent. 1984;51:797–800.

34. Laminate Technique
• It was described in 1951 by Schwartz.
• It combines reversible and irreversible hydrocolloid.
The tray hydrocolloid is replaced with a mix of chilled alginate, that
bonds with syringe agar .
Advantages: Disadvantages:
• Less preparation time
• Less complicated when compared to
the wet field technique
• Bond between agar & alginate is not
strong
• High viscosity alginate displaces agar
during seating
• Dimensional inaccuracy of alginate
limits the use to single units

35. • Fusayama developed the Laminated single impression technique where heavy &
wash silicone are mixed at the same time.
• The wash type is laminated in a thin layer on the surface of the heavy type & is
loaded in a tray & immediately impressed upon the preparation.
• The purpose of this lamination is to prevent the direct contact of the heavy type
with, the preparation, which roughens the stone surface.
• They concluded that the laminated single impression technique is clinically simple
& is capable of producing stone models having adequate dimensional accuracy &
sufficient surface reproducibility
Fusayama T, Iwaku M, Daito K, Takatsu T, Kurosaki N. accuracy of the laminated single impression technique with silicone material. J
Prosthet Dent. 1974; 32(3): 270 – 76

37. Modified Alginates -
1. Alginate in the form of sol - containing water but no source of calcium ions.
(paste form)
2. Alginates modified by the incorporation of silicone polymers (paste form)
Advantages - Fine detail reproduction & high tear resistance
Disadvantages - Poor dimensional stability

38. 1. Mixing
techniques
Double mix
Heavy-light body
technique
Putty wash
technique
One stage --
simultaneous
Two stage --
relief channel
-- 2 mm spacer
technique
Single mix or
mono-phase
technique
2. Tray used
Custom tray
impressions
Stock tray
impressions
Based on the mixing techniques & tray used

39. 1. Double mix technique (Multiple mix technique)

40. Advantages
• Overcomes the
polymerization
shrinkage of the light
body material
• Margins duplicated in
light body
Disadvantages
• An assistant required
for mixing the material -
tray/syringe
simultaneously
• Margins duplicated in
heavy body in case of
excess pressure

41. 2. Single mix technique

42. Advantages
• Reduced wastage of
the material
• Less time
consumption
• Avoids the time
involved in fabrication
of custom tray
Disadvantages
• Relatively high
viscosity and reduced
flow of the
monophase materials,
makes their injection
onto the preparation
more difficult to
control -increased
incidence of surface
voids
- Stephen M. Dunne et al 1998

43. Putty wash simultaneously technique
(One stage)

44. Putty wash relief channel technique
• Pre-operative putty impression is made intra orally
• In the area where the teeth are to be prepared impression material is
removed or channels prepared using putty cutter instrument
• The impression is then relined with low viscosity material

45. Advantages
• Impression can be
captured with the wash
materials
Disadvantages
• To confine the wash
material to area of
relieved impression
• If entire area is washed
- creates hydraulic
displacement of putty
impression resulting in
smaller dies
- Donovan TE 2004

46. Putty wash-2mm spacer technique
• 2 mm thickness wax spacer is prepared on a diagnostic cast,
occlusal stops are provided on non-functional cusps
• A putty impression is made with a stock tray resulting in a putty
custom tray with 2mm space for the wash material
• Putty custom tray is then washed with light body material

47. • The polymerization reaction of condensation silicones produces the volatile by-
product ethyl alcohol - dimensional change.
• Advances in the formulation - have increased the silica filler in the putty to over
75% which decreases the dimensional change.
• If a stock tray is available, a condensation reaction silicone impression can be
made using either the one-or two step putty wash technique (two step is
preferred over one step)
• However, a custom tray is available, use a light body syringe wash with a
medium or heavy - body tray material.
Impression making with Condensation silicone

48. In Custom Trays
• The one step impression technique
• The impression material can be delivered from either tubes /cartridge systems.
In Stock Trays
1. Two Step Putty Wash Techniques:
Most often used
• The putty can customize the stock tray and offer support and stability to the wash material.
• Addition silicones are not firm enough to be used in stock trays without putty or heavy body
as a tray material.
2. One Step Putty Wash Technique:
• Alternative to the two-step technique when a stock tray is used.
Impression making with Addition silicone

49. Impression making according to mixing
1. Automix technique
1. Impression material is supplied in prepackaged cartridges
with a disposable mixing tip attached.
2. The cartridge is inserted in a gun like device & the base &
catalyst are extruded into the mixing tip, where mixing
occurs as they progress to the end of the tube.
3. The homogeneously incorporated material can be directly
placed on the prepared tooth & impression tray.
4. Advantage: Elimination of hand mixing.
**A study conducted by Chong et al showed that elimination of hand mixing on
pad produce fewer voids in the impression.

50. 2. Machine mixing technique
• An alternate method for improving mixing is to use a machine mixer.
• Convenient & produces void-free impressions.

51. • Arch is broken down into segments of multiple prepared teeth
• Custom tray prepared for each segment with 1mm of wax relief
• Overlay trays should extend 3 mm beyond the gingival margin.
• Low viscosity material is loaded into the syringe as well as the segmental tray,
and then an impression made
• Procedure repeated with each segment
• Finally a pick up/ overlay impression is made using a stock tray
Uses
• When moisture control is difficult
• When making simultaneously impressions of implants and prepared teeth/
multiple prepared teeth
Miscellaneous Techniques
1. Segmental impression technique

52. Jung B-Y, Lee K-W. Alternative impression technique for multiple abutments in difficult case to control. The J
Adv Prosthodontics. 2010;2(1):1-3.

53. 2. Dual Arch Impression Technique
• This technique captures the prepared teeth, the opposing arch and the occlusal
articulation in maximum intercuspation (MIP) simultaneously.
Minimum conditions:
1. The articulator must have a vertical dimension holding stop such as an incisal pin or other
metal to metal contact.
2. If the articulator does not provide for a stop, there must be sufficient natural teeth remaining
to maintain vertical dimension.
3. There should be sufficient space distal to the terminal tooth in the arch to allow tray
approximation.

54. Indications
• Used with a maximum of two
prepared teeth
• Used only with patients that
have existing anterior
guidance
Contraindications
• Presence of third molars
• Rapidly ascending ramus
• Excess soft tissue distal to the
molars
Advantages
1. Accurate recording of the MIP
2. Eliminates any mandibular flexure that
might be associated with opening
Disadvantages
1. Complicated laboratory procedure
2. Tray is not rigid; depends on impression material
for rigidity.
3. Is not a functionally generated technique, so it is
limited to one casting per quadrant.
4. The distribution of the impression material is not
uniform.

55. Technique
Loaded tray seated in mouth Biting in MIP

56. • Gus J. Livaditis described a technique that requests a series of three
impression procedures using three types and/ or viscosities of impression
material.
• It overcomes deficiencies in registration of subgingival margins, gingival
retraction and relapse and delivery of impression material subgingivally.
3. The matrix impression technique

58. • While making an impression, implant copings can reduce access to the prepared teeth
and interfere in recording the margins of the prepared teeth.
• A useful method to precisely record the detail of the prepared teeth and the implants is
to use a combination of custom impression trays (individual trays) to impress the
prepared teeth and then place the implant impression copings and make an over-
impression of the arch.
• A heavy-bodied PVS impression material is placed in the individual custom tray and is
seated over the preparation(s).
4. Tooth implant impression makingChee WWL, Alexander M. Impression technique for arches requiring both implant and natural tooth restorations. J Prosthodont
1998;7:45.

59. • The heavy-body impression material is allowed to set, and the impression tray is
removed.
• The impression and tray are perforated through the occlusal surface with a round bur.
• This preliminary impression is then filled with light-body material and replaced over the
prepared teeth.
• The hydraulics pressure forces the light body impression material beyond the prepared
sub-gingival margins.
• The implant copings are then attached, and an over-impression is made.
• Two different techniques are followed i.e., an indirect/closed tray technique and the
direct/open tray technique.
• The procedure is as follows

62. • The first commercially available CAD/CAM system for fabricating dental restorations
was introduced in 1987 (CEREC [chairside economical restoration of esthetic
ceramics], Sirona).
• It uses optical scanning and requires the entire area to be captured in the
impression, to be coated with a reflective powder.
• There were two digital impression systems introduced in 2008 that were not
connected directly to a milling machine :
1. The iTero system (Cadent) uses a laser scanner that does not require reflective
powder to facilitate the impression.
2. The Lava Chairside Oral Scanner (COS) (3M ESPE) uses light powder to facilitate
scanning by an optical video system.
5. Digital impressions

63. • A dual-cord retraction technique is recommended.
• After the preparation, a thin cord is placed and an initial scan is made.
• The areas on the preparation that need modification are then refined.
• Thicker cord is placed & the final scan is then accomplished.

64. Digital impressions - Stepwise procedure

65. • Elastomers are strong enough to reproduce a pinhole without tearing
• However to ovoid bubbles :
 Cement tube : the tube filled with impression material is squeezed into
each pinhole, making sure no air is trapped by inserting and removing an
explorer into the material
 Lentulospirals : rotated slowly along the sides of the pin-hole
• Reversible hydrocolloid - special nylon bristles are used to register the pin
hole
7. Pin related restorations

66. Lentulo:-
- Pick up a small quantity of impression material & spiral the material into the pinholes,
rotating slowly while moving the lentulo along the side of the pinhole.
Prefabricated plastic pins:-
- Bristles, used to register the pinholes can be modified with a scalpel to
eliminate inaccuracy relating to fit.
- Length should be adjusted so that they do not contact the impression tray. Place
the bristle & complete impression.

67. • The elastomeric impression should be reinforced with a plastic pin or orthodontic wire.
Direct Procedure:-
1. Lubricate the canal & notch a loose fitting plastic dowel that extends to the full depth
of the prepared canal.
2. Use bead-brush technique to add resin to the dowel & place resin into the canal.
3. Do not allow the resin to harden fully within the canal.
Loosen & reseat it several times while its rubbery.
4. Once polymerized, remove the pattern & build up the core
8. Impression technique for post & core

68. Indirect Procedure:-
1. Cut pieces of orthodontic wire to length & shape them like letter “J”.
2. The wire should fit loosely & extend to the full depth of the post space.
3. Coat the wire with tray adhesive.
4. Using lentulo spiral, fill the canal with elastomeric impression material.
5. Seat the wire reinforcement to the full depth of post space, syringe more impression
material around the prepared teeth, & insert the impression tray.
6. Remove the impression & pour cast.

69. • Indirect dowel cores - when multiple dowel cores are required or when
radicular attachments are to be used
• A 25 gauge local anesthetic needles - vent to allow air to escape as the
impression material is injected into the canal space
• Needle is gradually removed while the low viscosity materials is injected into
the canal
• Plastic impression dowel coated with adhesive is inserted into the canal
• Procedure is repeated with multiple dowels and finally an over impression is
made

70. Trebilcock CE , Evans DB. A two-stage impression technique for the indirect fabrication of multiple cast dowel and cores. J
Prosthet Dent. 1991 Oct;66(4):422-5.

71. Advantages
• Increased hardness of the
die
• Excellent abrasion resistance
• Die is so strong that wax
patterns & gold castings can
be burnished with little
distortion or damage to the
die
Disadvantages
• Toxicity of cyanide baths
• Time required to prepare
the die
• Expense of labor and
materials
• Limited control of die
accuracy
9. Electroplating
It is the electro deposition of metals (silver, copper) on the surface of the impression
to improve the abrasion resistance of gypsum

72. Disinfection
• It is necessary to disinfect impressions before pouring the cast or sending to
lab.
• The first step is to rinse the impression in tap water – removes microbes,
otherwise microbes will be protected by saliva/blood.
• Disinfection reduces the number of germs by at least a factor of 105.
• An alternative to disinfecting impressions is to use disinfected die stones
• Spray disinfection- not preferred as complete surface wetting is not ensured..

73. • Alginates- cast immediately OR stored in hygrophor / in a resealable plastic bag together
with a moist paper towel.
• Agar- cast immediately OR wet towels, humidors, water baths, 2% K2SO4 solution.
• C-silicone or polysulfide- cast in 30 mins(dimensionally unstable)
• Polyether - impressions send separately from alginate impressions
- transported and stored dry, cold and protected from direct sunlight can be kept
for up to two weeks.
• VPS - most favourable material properties for storage.
- kept & transported dry; not above room temperature.
Storage & transport

74. 1) The copper band impressions do not require gingival retraction but it traumatizes the gingiva.
2) A reversible hydrocolloid gives the most precise impression but production of accurate working
dies is difficult.
3) The irreversible hydrocolloids provides the least accurate complete arch impressions.
4) Of all the elastic impressions the polyvinyls and polyethers are more stable to deformation.
5) Storing the impressions at 4°C, then allowing the impression material to reach room
temperature, results in slight expansion of the impressions which partially compensates the
contraction during polymerization of the material.
M Curso. Effect of temperature changes on dimensional stability of polyvinyl siloxane and polyether impression materials. Int J Prosthodont. 1998;79:626–631.
To summarize key points

75. 6) A complete dry field and latex-free gloves are essential when impressions are made with
addition silicone.
7) Polyether produces the best detail reproduction under moist conditions.
8) The use of metal trays results in superior dimensional accuracy and reliability of impression
making (Markus B et al), the use of custom tray produced dies that were much more
accurate than the stock trays (Gilmore et al)
9) A lower-viscosity wash material produces more precise impressions.
10) A two-stage putty wash technique provides a good reproduction only when a spacer of
2mm is provided in the first stage.
11) In the matrix impression system, the matrix dispenses the impression material into the
sulcus with greater precision and consistency in comparison with a syringe.

76. 12) The monophase technique using either polyether or vinyl polysiloxane, produces better
detail when compared to the dual-viscosity technique.
13) The use of rewash impression technique to correct impressions is not recommended.
14) The one-step putty-wash technique, records and reproduces the finish line better than
two step technique.
15) All-ceramic crowns fabricated from digital intraoral impressions demonstrate better
marginal fit than conventional two-step impressions.
***Pradíes G., Zarauz C., Valverde A., Ferreiroa A., Martínez-Rus F. Clinical evaluation comparing the fit of all-ceramic crowns obtained from
silicone and digital intraoral impressions based on wavefront sampling technology. Journal of Dentistry. 2015;43(2):201–208. doi: 10.1016
16) The precision of the digital complete-arch impression are less accurate than a
conventional impression.
***Ender A, Mehl A. Accuracy of complete-arch dental impressions: a new method of measuring trueness and precision. J Prosthet
Dent. 2013;109:121–128.

77. • An important factor that ensures long-term success in fixed dental prosthesis is
a precise record and reproduction of the prepared teeth, soft tissues and
adjacent structures.
• Excellent impressions require accurate and stable impression materials, time
and a thorough working knowledge of all the aspects of the concepts involved.
• If the clinician continues to have ill-fitting restorations, it may not only be due
to inadequacy of the impression materials, but rather due to unacceptable
clinical procedures.
Conclusion

78. 1. Schillingburg: Fundamentals of fixed prosthodontics, 3rd edition.
2. Stephen F. Rosenstiel - Contemporary fixed prosthodontics, 3rd edition.
3. John F.McCabe & Angus W.G Walls, Applied Dental Materials, 8th ed.
4. Skinners science of dental materials, 9thth edition.
5. Robert G Craig, Restorative dental Materials, 9th edition.
6. William J O`Brien, dental materials and their selection, 3rd edition.
7. Pod Shadley A.G.- Electrosurgical procedures in crown and bridge restorations J. Am Dent Assoc 77:
1321; 1968.
8. Charles Culbreath D.D.S - An impression technique for cast restorations J. Prosthet. Dent 1975 Apr 33 (4).
9. Leesinger: Simplified copper tube impression for full crown coverage J. Prosthet. Dent 1976 Nov. 36 (5).
10. Andrew J. Cannis Trac: A new approach to impression taking for crown and bridge Dental Clinics. North
America.
11. Tylman. S.D. and Fylman S.G.: Theory and practice of crown and bridge prosthodontics 8th edition.
12. Robert E. Going. Accurate rubber-base impressions. J. Prosthet. Dent 1968 Oct 20(4).
References

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15. Kirk Gardner and Gerald H. Loft: An intraoral coping techniques for making impressions of
multiple preparations. J. Prosthet. Dent 1981 May 45 (5).
16. Barry Marshak and David Assit. A controlled putty – Wash impression technique. J. Prosthet.
Dent 1990 Dec 64 (6).
17. Jamsludi M: Technique for accurate rubber base impression for fixed prosthodontics. J.
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18. Carrotte P.V., Johnson A: The influence of the impression tray on the accuracy of impression
for crown and bridge work - an investigation and review Br. Dent. J. 1998; 185: 580585.
19. Robert E. Going. Accurate rubber-base impressions. J. Prosthet. Dent 1968 Oct 20(4).
20. Anthony La Forgia. Multiple abutment impressions using vaccum adapted temporary splints.
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21. Edwin H.Getz et al., A full arch interocculusal impression tray to eliminate lack of coverage
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80. THANKYOU !