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By - Dr. Anupriya Singh P.G. 1 st Year ELASTOMERIC/ RUBBER- BASE IMPRESSION MATERIALS ( Part – 2 )

Elastomeric impression techniques

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based on JPD articles.

Text of Elastomeric impression techniques

By Dr. Anupriya Singh P.G. 1 st Year

Impression Techniques Comparison Various commercially available Elastomers References


TECHNIQUE (single step putty wash technique) SINGLE VISCOSITY OR MONOPHASE TECHNIQUE TWO-STEP PUTTY WASH TECHNIQUE OTHERS 1. The matrix impression system Gus J. Livaditis . 2. A simplified custom impression technique Steven J. Sadowsky .

Before making an impression the following 2

criterias are to be kept in mind 1.

Which elastomer is to be used the current choice being condensation curing silicone, addition-curing silicone or polyether. Which technique is to be employed either single impression (using a material presented as one viscosity, as is often the case with polyethers and the so called monophase silicones), or using a two-body combination (as is generally the case with either form of silicone).Brown D.: Materials for Impressions 2003. Dent Update 2004; 31: 4045


In this method the wash material is syringed

into place & then unset putty is seated over light body material.

Wu and Donovan in 2007 in the Journal of

Prosthetic Dentistry.

With the 1-step procedure, low viscosity

impression material is injected around the prepared tooth or teeth, and then the putty impression material is immediately placed intraorally and the materials polymerize simultaneously.

This article describes a modified 1-step putty-

wash technique using vacuum-formed resin sheets as spacers to control the wash bulk. PROCEDURE Use the original diagnostic cast or cast recovered from an impression of the diagnostic provisional restorations to fabricate the vacuum-formed spacer.

Cast recovered from impression for provisional restoration on mandibular right first premolar.

Place the cast and a 5 x 5-inch sheet of 0.08-inch-

thick soft clear ethyl vinyl acetate on a singlechambered vacuum-forming machine . Heat until a 0.5-inch droop develops, and then vacuum form the spacer on the cast.

Do not prepare occlusal stops because they

interfere with the removal of the spacer from the putty. Trim the spacer with scissors and a hot knife to cover approximately 2 to 3 mm of marginal gingiva on the buccal and lingual surfaces of the teeth.

Vacuum-formed spacer fabricated on cast recovered from impression for provisional restoration.

Complete essential gingival displacement

procedures on prepared teeth. Place the vacuum-formed spacer intraorally and verify stability. Make a transfer impression of the spacer with high-viscosity putty impression material in a stock tray .

Vacuum-formed spacer on internal surface of putty pick-up impression.

Before the putty impression material is

polymerized, remove the entire impression from the mouth and gently remove the spacer from the putty material. Simultaneously wash the putty tray with lightbodied vinyl polysiloxane impression material to make the definitive impression.

Internal surface of washed putty impression.

Also called as the Single Viscosity technique. A medium body material is used in this technique

intraorally at the prepared site and as a tray material . Stock trays are conventinally used in this

technique. Polyethers and Addition Silicones.Craigs Restorative Dental Materials Eleventh Edition

PROCEDURE Its a technique that uses monophase materials to

accomplish an impression in a single-step procedure, using materials with a medium viscosity to allow the material itself to record the finer details while avoiding the slumping of the material in the tray.

Caputi S.,Varvara G.: Dimensional accuracy of resultant casts made by a monophase, one-step and two-step, and a novel two-step putty/lightbody impression technique: An in vitro study. J Prosthet Dent. 2008 April;99(4):274-81

First , thick putty material is placed in stock tray. Primary impression is made , resulting in intraoral custom-made tray formed by putty. Space for light-body wash material is provided by cutting some tray putty or by using various spacers. After spacer is removed thin consistency wash material is placed into putty impression . Putty wash is seated in mouth to make final impression.

The wash impression material is used to -

obtain the detail of the prepared abutment tooth and adjacent teeth. 2. compensate for deformation that occurs when the prepolymerized putty impression material is removed from the mouth.1.

Chaimattayompol N, Park D.: A modified putty-wash vinyl polysiloxane impression technique for fixed prosthodontics. J Prosthet Dent 2007;98:483-485.

Chaimattayompol and Park - 2.0 mm of relief is

recommended to achieve predictable definitive impressions with dimensional accuracy when using a 2-step putty-wash impression technique. (J Prosthet Dent 2007;98:483-485) There are a number of spacers that provide the

recommended relief in the impression.

The spacers used are as follows 1.


3. 4. 5.

A spacer created by grinding away some of the putty impression material after the impression is made. J. Nissan et al - a polyethylene spacer (plastic spacer used with the putty impression first and then the wash stage). ( J Prosthet Dent 2000;83:1615.) J. Nissan et al stainless steel prefabricated copings. ( J Prosthet Dent 2000;83:161-5.) Wu and Donovan - vacuum-formed resin sheets as spacers. (J Prosthet Dent 2007;98:245-246.) Monzavi and Siadat - baseplate wax as a spacer. (J Prosthet Dent 2005;93:494.)

Chaimattayompol and Park in 2007 in the Journal of

Prosthetic Dentistry. The technique presented in this article is a modification of a 2-step putty- wash impression technique without using a spacer. It uses the concept of primary pressure from partial polymerization (30 seconds after mixing) of a fast-set putty material that is impressed while placed around the prepared abutment tooth, which then helps push the wash impression material subsequently injected to record details of tooth preparation.

PROCEDURE Select a stock tray appropriate for the dental arch

to be impressed and apply vinyl polysiloxane impression tray adhesive Place retraction cord in the gingival sulcus. Mix putty base and catalyst impression material for 30 seconds, and quickly load into the impression tray. Insert the loaded impression tray intraorally while the retraction cord is still in place, and maintain the tray in position for approximately 30 seconds. Ensure that the tray handle is oriented to the facial midline for future reference. Remove the impression tray from the mouth.

Remove the retraction cord and immediately

syringe extra-light impression material onto the prepared abutment and adjacent teeth.

Extra-light-body impression material on prepared abutment and adjacent teeth.

In the meanwhile a dental assistant loads the

wash impression material onto the prepolymerized putty impression .

Extra-light-body impression material on impression surface of prepolymerized putty impression in impression tray.

Reinsert the impression tray into the same

position and allow the material to polymerize for the time period recommended by the manufacturer. Separate the impression tray from the mouth and examine the definitive impression.

Complete arch definitive impression. Note there is no delamination between 2 impression materials.


it allows a prepolymerized putty impression material to anatomically form around the prepared abutment tooth and, therefore, in the authors opinion, create greater pressure, forcing the wash impression material so that it penetrates into the gingival sulcus more easily. 2. accurate detail can be obtained without the need for a custom- made matrix to assist in making a definitive impression. 3. it is less time-consuming when compared to the 2-step putty-wash impression technique. 4. there is no delamination between the 2 different viscosity impression materials (putty and wash).1.

The primary disadvantage of this technique is

that it is time-sensitive And requires coordination between a dentist and a dental assistant to inject the light-body material into the prepared tooth and prepolymerized fast-set putty impression immediately upon removal from the mouth. However, a single operator without a dental assistant can accomplish the same technique by using the regular set impression material. The use of a cheek retractor is also helpful to facilitate this process.

The matrix impression system Gus J. Livaditis .

A simplified custom impression technique Steven J. Sadowsky .

Gus J. Livaditis in 1998 in the Journal of Prosthetic

Dentistry. This technique focuses on making successful

subgingival impressions. Four forces that must be controlled when making

subgingival impressions are retraction forces, displacement forces, collapsing forces, and relapsing forces.

MATERIAL AND METHODS The MIS uses three impression materials:

a suitable elastomeric semirigid material required to form the matrix. 2. a high viscosity elastomeric impression material, which will preferably bond to the matrix-forming material, required to make an impression of the preparations in the matrix. 3. a stock tray with a medium viscosity elastomeric impression material to pickup the matrix impression and the remaining arch not covered by the matrix.1.

CLINICAL PROCEDURE Forming the matrix Immediately after tooth preparation and before

any retraction procedures, select or create a carrier for the matrix forming material.

Maxillary anterior teeth prepared for full crowns

Clear plastic carrier selected from assortment of premade forms. Carrier may also be made of wax.

The carrier should provide 3 to 4 mm of space

between its walls and the prepared teeth and 2 to 3 mm between its walls and adjacent unprepared teeth. It should extend one tooth beyond the prepared teeth on both sides when teeth are present. It should also extend 2 to 3 mm onto the ridge beyond the margin of the gingiva. All soft tissues under planned pontics and precision attachments should be included within the matrix carrier.

Fill the carrier with PVS occlusal registration

material and position it over the prepared teeth. The carrier should be held to create a 1 to 2 mm thick occlusal wall over the unprepared teeth.

Matrix is made in carrier with polyvinyl siloxane material before soft tissue is retracted. Registration of gingival crest is primary objective. Tissue under planned pontics and precision attachments should be included.

Facial and palatal sides of matrix are trimmed with scalpel. Matrix should extend one half to two thirds of tooth beyond prepared teeth and close to gingival crest. Black lines indicate sulcular extension.

Refining the matrix Mark the facial side of the matrix to maintain

proper orientation throughout the trimming and impression phase. Trim the outer aspect of the matrix extending onto the ridge to remove all material that overlaps the gingival tissue. Scalpels and straight handpiece aluminum oxide abrasive stones are effective. The angle of trimming is not critical, but the thickness of the matrix should be maintained between 1 and 3 mm. The outer portion of the matrix is trimmed to the gingival crest. Identify the crest of the gingiva and the sulcular extension, and mark them with a colored marker.

Part of matrix is colored to indicate important

structures. Thin black line around each preparation identifies sulcular extension but not necessarily finish line of preparation. Thick red line indicates crest of gingiva. Two black marks point out proximal contacts that must be relieved.

Slender bur or knife edged rubber wheel used to

enlarge interproximal embrasures. This permits lateral displacement of gingiva when impression material is guided into sulcus.

Mounted fast cut stone is used to relieve internal

walls of each preparation 0.25 to 0.50 mm. Trimming of matrix is complete. Original marks in matrix on incisal surfaces are left intact.

Abrade all external aspects of the matrix with the

trimming stone to remove any glossy surfaces formed by the carrier and/or to remove any contamination by wax. The roughened texture will improve adherence of adhesives or impression materials. Mark the facial surface again to prevent confusion of the proper orientation once the matrix is filled with impression material. When the impression is to be delayed to another appointment, the matrix should be labeled with the patients name or number and stored in a clean environment.

Completing the impression Remove the interim restoration and clean the

preparations. Seat the refined matrix on the prepared teeth and select a stock tray to accommodate the matrial and other unprepared teeth.

When the matrix is made with PVS material, apply

a thin layer of adhesive. (When polyether impression material is used for the matrix, the matrix impression, and the pick-up impression in the stock tray, no adhesive is required except on a non-perforated stock tray.) Place retraction cord around each tooth leaving one end of each cord protruding 2 to 3 mm for easy retrieval.

Mix high viscosity impression material and load it

in a conventional impression syringe. Dispense the material to fill the preparation depressions of the matrix , then apply the material generously around all of the soft tissue side.

Remove all retraction cords. Optionally,

additional material from the syringe may be dispensed around the prepared teeth. It is not essential to direct this material into the sulcus because that objective will be accomplished by the matrix. Matrix impression is seated with light pressure. Axial walls and positive vertical stops make proper seating easily discernible. Mark may be placed on facial surface for proper orientation, because many references are covered with impression material.

Stock tray filled with medium viscosity

impression material is seated over matrix impression before matrix material polymerizes.

After the impression materials have completely

polymerized, remove the impression and examine it for defects. The matrix is often visible through the matrix impression material. This is acceptable because the matrix was formed with a quality impression material and becomes integrated into the impression. When the impression is acceptable, form the master cast according to a desired procedure.

Steven J. Sadowsky in 2005 in the Journal of

Prosthetic Dentistry. This method describes the use of a matrix to

modify a stock tray, precluding the need for a custom tray or putty-wash system.

PROCEDURE Make a vacuum-formed, 0.20-inch-thick, clear

template on the diagnostic cast using the vacuum adapter. Cut the template at the interproximal junction of

the tooth or teeth to be prepared, leaving 3mm of matrix beyond the cervical finish line on the buccal and lingual surfaces, for correct seating.

After syringing the wash impression material on

the preparation(s), fill the internal portion of the adapted template with higher-viscosity impression material and seat over the preparation(s).

Adapted vacuum-formed template placed only over preparation, filled with higher-viscosity impression material.

Fill the stock tray with higher-viscosity

impression material and seat intraorally. Allow the material to polymerize according to the manufacturers recommendations .

Definitive impression.

The single stage putty wash technique is

unacceptable because it is impossible to control the thickness of impression material and excess bulk is used. It is impossible to control what material records the margin detail of the preparation(s). Usually portions of the prepared margin are captured in the putty, and putty materials are essentially deficient in their ability to record marginal detail.Donovan T.E. et al: A review of contemporary impression materials and techniques. Dent Clin N Am 2004;48:445470

According to Wu and Donovan the disadvantages

of the single step putty wash technique include lack of control of the bulk of wash material and the high risk of capturing portions of the prepared margin in putty material rather than lower viscosity material. Most putty viscosity materials have inadequate fine detail reproduction for this purpose. (J Prosthet Dent 2007;98:245-246)

The potential pitfalls of the two-step putty wash

technique where relief is provided at the preparation site are It is difficult to confine the wash materials to the area of the relieved impression, and some wash material enters the unrelieved impression. This results in an inaccurate occlusal pattern for the resultant cast. Thus, the entire impression, rather than just the relieved area, should be washed.Donovan T.E. et al: A review of contemporary impression materials and techniques. Dent Clin N Am 2004;48:445470

This creates the potential problem of hydraulic

distortion of the putty material as the impression is seated in the mouth. This is impossible to detect on a clinical level but may have a deleterious effect on the accuracy of the impression and resulting restoration.

Donovan T.E. et al: A review of contemporary impression materials and techniques. Dent Clin N Am 2004;48:445470

According to Nissan et al - The putty/wash 2-step

impression technique was the most accurate for the fabrication of stone dies and resulted in precise castings. Tendency for bubbles to form in the set impression, occurs more in the 1-step impression technique than in the 2-step one. The critical factor that influences the accuracy of the 2-step putty/wash impression technique is the control of wash bulk, which is absent in the 1-step techniques. Moreover, in this techniques, only the putty duplicates parts of the prepared teeth, including the margins. Most putties cannot reproduce the fine details.

Millar et al - The use of monophase materials in

stock trays resulted in a significantly greater number of surface voids compared with the conventional two-phase materials used in custom trays. This finding is attributed to the relatively high viscosity and reduced flow of the monophase materials, which makes their injection onto the preparation more difficult to control. The increased viscosity of monophase materials, necessary to prevent large masses of material from slumping, may well adversely affect the flow of the material over the prepared tooth. This may have made the placement less accurate and so incorporated voids.

POLYSULPHIDES BRAND NAME Permlastic Omni-flex Coe-flex Kerr GC America GC America SUPPLIER

ADDITION-CURING SILICONES BRAND NAME Affinis Aquasil Dimension Garant Doric Elite HD Exaflex Express Extrude Flexitime Imprint II President Provil Novo Reprosil Zerosil SUPPLIER Coltne/Whaledent Dentsply De Trey 3M ESPE Schottlander Zhermack GC America 3M ESPE Kerr Hawe Heraeus Kulzer 3M ESPE Coltne/Whaledent Heraeus Kulzer Dentsply DeTrey Dreve


BRAND NAMES Coltex Optosil/Xantopren

SUPPLIER Coltne/Whaledent Heraeus Kulzer


Craig RG., Powers JM.: Restorative Dental

Materials; 11thedition, 2002. Donovan TE. et al: A review of contemporary impression materials and techniques. Dent Clin N Am 2004;48:445470. Brown D.: Materials for Impressions 2003. Dent Update 2004; 31: 4045. Livaditis GJ.: The matrix impression system for fixed prosthodontics. J Prosthet Dent 1998; 79:208-16.

Sadowsky SJ.: A simplified custom impression

technique. J Prosthet Dent 2005;94:468-9. Nissan J, Laufer BZ, Brosh T, Assif D.: Accuracy of three polyvinyl siloxane putty-wash impression techniques. J Prosthet Dent 2000;83:161-5. Wu AY, Donovan TE.: The use of vacuum-formed resin sheets as spacers for putty-wash impressions. J Prosthet Dent 2007;97:54-5. Caputi S.,Varvara G.: Dimensional accuracy of resultant casts made by a monophase, one-step and two-step, and a novel two-step putty/lightbody impression technique: An in vitro study. J Prosthet Dent. 2008 Apr;99(4):274-81

Wu AY, Donovan TE.:A modified one-step putty-

wash impression technique. J Prosthet Dent 2007;98:245-246. Chaimattayompol N, Park D.: A modified puttywash vinyl polysiloxane impression technique for fixed prosthodontics. J Prosthet Dent 2007;98:483485. Monzavi A, Siadat H. Use of wax spacers for puttywash impression of implant snapon impression copings. J Prosthet Dent 2005;93:494. Millar BJ.: In vitro study of the number of surface defects in monophase and two-phase addition silicone impressions. J Prosthet Dent 1998;80:32-5.


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