|Year : 2017 | Volume
| Issue : 1 | Page : 55-58
A modified technique for making putty-wash two-step impression
Sunil Kumar Mishra1, Puja Hazari2, Ramesh Chowdhary3, Shail Kumari4
1 Department of Maxillofacial Prosthodontics and Implantology, Peoples College of Dental Sciences and Research Centre, Bhopal,
Madhya Pradesh, India
2 Department of Maxillofacial Prosthodontics and Implantology, Peoples Dental Academy, Bhopal, Madhya Pradesh, India
3 Department of Maxillofacial Prosthodontics and Implantology, Rajarajeshwari Dental College, Bengaluru, Karnataka, India
4 Department of Orthodontics and Dentofacial Orthopaedics, Rishiraj College of Dental Sciences and Research Centre, Bhopal, Madhya Pradesh, India
|Date of Submission||15-Feb-2017|
|Date of Acceptance||11-May-2017|
|Date of Web Publication||1-Jun-2017|
Sunil Kumar Mishra
Department of Maxillofacial Prosthodontics and Implantology, Peoples College of Dental Sciences and Research Centre, Bhopal, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
Background: If the impression thickness is uniform, stock trays can also give a better result when compared to custom trays.
Purpose: This study aimed to obtain a uniform thickness impression with a modified putty-wash two-step technique.
Materials and Methods: A chairside method of putty-wash two-step impression in a stock tray was made utilizing a wax spacer.
Results: A uniform thickness impression was obtained in stock tray in quick time.
Conclusion: The current article has given the options of using wax as spacer for making putty wash two step impressions for the fabrication of tooth-supported fixed restorations. Further research is required to find whether there is any dimensional inaccuracy caused in restorations due to usage of wax as a spacer.
Keywords: Custom tray, elastomers, impression, stock tray
|How to cite this article:|
Mishra SK, Hazari P, Chowdhary R, Kumari S. A modified technique for making putty-wash two-step impression. BLDE Univ J Health Sci 2017;2:55-8
One of the most important steps in the fabrication of fixed partial denture is making of accurate impression. Among all the impression materials available, nonaqueous elastomeric impression materials are considered to be the most accurate in dimensional stability and surface detail reproduction. There are different impression techniques available for elastomeric impression materials such as (a) putty-wash, two-step technique with polyethylene spacer, using a stock tray; (b) putty-wash, one-step technique, using a stock tray; (c) single-mix technique, utilizing medium viscosity in a custom tray; and (d) multiple-mix technique, utilizing a heavy- and low-viscosity combination in a custom tray. There is much discussion in the dental literature regarding the effect of impression technique on the accurate fit of cast restorations. Hung et al. reported that the accuracy of addition silicone was affected more by the type of materials than by the technique, while Johnson and Craig  stated that accuracy could be better controlled with technique than by the material itself. An accurate impression which can register the entire details of oral structures requires uniform thickness of impression material. Many studies ,,, had reported that custom trays provide more accurate dental casts than stock trays, but if stock trays are properly oriented and the impression thickness is uniform, stock trays can give better result than custom trays., This article describes a modified method of impression making to obtain a uniform thickness impression with putty-wash two-step technique.
| Materials and Methods|| |
Custom trays have been recommended to produce more accurate impressions, but stock trays remain in popular use. Mishra and Chowdhary  and Valderhaug and Fløystrand  in their study found that the linear dimensional stability of the impression made in stock trays was not inferior to the stability of impressions made in custom trays. The two different putty-wash techniques that are commonly used in a stock tray are: (1) Putty-wash one-step technique (2) putty-wash two-step technique. This article describes a quick and easy method of making putty-wash two-step impression in a stock tray utilizing wax spacer to control the bulk of the wash impression material.
Steps of modified impression technique in stock tray
A modified technique was done in which first the base plate wax sheet was cut in the maxillary arch form [Figure 1]a. The wax sheet was gently softened in warm water and care was taken that it should not melt and stick on the tooth. The wax sheet was adapted over the tooth region of the maxillary dentulous arch to create space for the wash impression material [Figure 1]b. The putty consistency of elastomeric impression material was manipulated and loaded in a stock tray and placed over the adapted wax sheet on the maxillary arch and allowed to set. The tray was removed along with the wax spacer in it [Figure 2]a. The wax spacer was removed from the putty impression and inspected so that any residual wax should not left in the impression [Figure 2]b. The tooth surface was thoroughly cleaned to remove any wax residues adhered to it. The light-bodied elastomeric impression material was manipulated and loaded in the space created by the wax spacer in the stock tray and the final wash impression was made with uniform thickness of light body impression material [Figure 3].
|Figure 1: (a) Wax sheet cut in the form of maxillary arch. (b) Wax sheet adapted over the maxillary dentulous arch|
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|Figure 2: (a) Putty impression with wax spacer. (b) Putty impression after removal of wax spacer|
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This modified impression was cost-effective as stock trays are economical and very convenient to use. Stock trays can be used in a single visit as they are easily selected and adapted in patient's mouth. Custom tray requires proper planning, a study model, laboratory time, a curing interval, and lot of finishing time, so they are costly and used only once. In this technique, the amount of light body impression material required was controlled with the use of uniform thickness of wax sheet, so the amount of light body material can be saved and the impression will be cost-effective.
| Results and Discussion|| |
The modified impression technique provides putty impression along with a uniform thickness of light body impression in a stock tray in quick time.
For making an accurate impression, a uniform wash impression is needed. Nissan et al. recommended the use of two-step technique for accurate impression making as there is uniform wash space for the light body material to polymerize. In the two-step, double-mix, putty-wash impression technique using stock tray without spacer, the thickness of wash material is not uniform. In two-step, double-mix, putty-wash impression technique with spacer, polyethylene spacer or vacuum-formed resin sheets are used as spacers. When using polyethylene sheet, there is a risk of getting it folded while making impression. Although with vacuum-formed resin sheets we can get a uniform thickness of impression, but this technique needs special armamentarium, laboratory time, and extra cost.
Custom tray with elastomeric impression material or a stock tray with a putty-wash is used for making an impression of dental implants. Impressions for implant-fixed restorations are usually made in one step. Gregory-Head and LaBarre described two-step pick-up impression procedure for implant-retained overdentures. Patil and Muley  described a modified two-step putty-wash impression technique for implant restorations where they had adapted a double-thickness modeling wax around the impression copings and made the impression with a putty elastomeric impression material followed by addition of the light body impression material on the spacer and wax areas of the putty impression and made the final impression. Monzavi and Siadat  used wax spacers for putty-wash impression of implant snap-on impression copings in their article. Thongthammachat et al. stated that the clinical significance of any investigation is related to their tooth-to-tooth relationship. If distortion occurs within the limit of periodontal ligament space, the deviation should be acceptable. The periodontal ligament space has been reported to range from 90 to 240 μm. A change of 90 μm should be clinically acceptable.
The modified impression technique stated in this article for making putty-wash two-step impressions in a stock tray utilizing a wax spacer is economical and convenient. Stock tray can be selected, adapted, and used in a single visit. It does not require any study model and laboratory procedure. Finally, wax spacer provides controlled bulk of the wash impression material.
There may be issues regarding bond strength of putty to wash impression material when a wax spacer is used. Researchers , had previously used wax as spacer for putty-wash two-step technique for implant restorations. Sandrik and Vacco studied bond strength of different putty-wash elastomeric impression materials. In a study, one manufacturer recommended placement of boxing wax over the teeth as a spacer while the initial impression was made to provide space for the wash material. The bond strength found was 79 Psi which was even greater than the bond strength (70.5 Psi) of other techniques where impression was made without wax spacer. The study did not showed decrease in bond strength even though the wax spacer was used.
The disadvantage of using vinyl polysiloxane (VPS) impression materials was their hydrophobic characteristics due to which moisture has been reported to result in impressions with pitted surfaces. Surfactants were added to improve the property of VPS and make them hydrophilic in nature and thus they improve the wettability of the polymerized impression. The effect of wax spacer on the property of elastomeric impression material can still be a matter of debate. Wassell et al. stated that controlling the thickness of the wax spacer is not easy, and the resultant impression may not provide the desired accuracy. Study by Sandrik and Vacco did not show decrease in bond strength although the wax spacer was used, but it was an in vitro study and the technique presented in this paper is an in vivo technique.
| Conclusion|| |
The present article has given the options of using wax as spacer for making putty wash two step impressions for fabrication of tooth-supported fixed restorations. Further research is required to find whether there is any dimensional inaccuracy caused due to usage of wax spacer or its effect on bonding of putty to light body consistency of the impression material. Precaution was taken to eliminate any wax present on the tooth surface to reduce the incorporation of any possible inaccuracy in impression, but still in vitro and in vivo studies are recommended to analyze the benefit and drawbacks to follow it in the clinical practice.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]