Modified One Step Putty Wash Technique
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This article describes a modified one-step putty-wash impression technique that uses vacuum-formed resin sheets as spacers. The resin sheets are vacuum formed on a diagnostic cast to create spacers that are placed in the mouth during the impression to control the thickness of the light-body material. The putty material is used to make an impression of the teeth and spacers together. Then the spacers are removed and the light-body material is used to wash the definitive impression. This technique aims to control the thickness of the light body and minimize the disadvantages of a standard one-step technique.
Modified One Step Putty Wash Technique
- 1. A Modified One-step Putty-wash Impression Technique Yu-Jen Wu A. & Donovan T.E J Prosthet Dent 2007;98:245- 246
- 2. Literature demonstrates that optimum accuracy can be achieved with Custom trays and Stock trays
- 3. Numerous studies have compared accuracy of polyvinyl siloxane impressions made with custom tray and stock trays. Custom Tray Stock Tray •PMM TRAY •PVS PUTTY TRAY •PHOTO CURE BISACRYL RESIN PLASTIC METAL PMM trays should be fabricated 24 hours in advance to insure stability. Donovan TE, Chee WW. A review of contemporary impression materials & techniques . Dent Clin North Am 2004;48:445-70.
- 4. Metal and rigid plastic stock trays give greater accuracy in the putty/wash silicone twin mix impression technique compared with flexible plastic ones for crown and bridge work. Those using the latter should be aware of their shortcoming in this respect. Carrotte PV et al. The influence of the impression tray on the accuracy of impressions for crown and bridge work-- an investigation and review. Br Dent J. 1998 Dec 12- 26;185(11-12):580-5.
- 5. Custom trays produced dies that were more accurate overall when compared with those produced by stock trays. Glenn E. Gordon et al. The effect of tray selection on the accuracy of elastomeric impression materials. J PROSTHET DENT 1990;63:12-5.
- 6. Elastomeric impressions are most accurate when used with a cross sectional thickness of approximately 2 mm. This thickness is optimally provided with a custom tray. Eames WB, Sieweke JC, Wallace GW, Rogers LB. Elastomeric impression materials: effect of bulk on accuracy. J Prosthet Dent 1979;41:304.
- 7. The putty-wash impression technique using an elastomeric impression material is a popular method.
- 8. Variations of the Putty-wash impression technique 1-step 2- step
- 9. 2-step technique First a preliminary pre-operative putty impression is made (to customize the tray) Then subsequently it is "washed" or “relined” with low viscosity material after tooth preparation.
- 10. In terms of the 2-step putty-wash impression technique, several methods are described for control of the bulk of the wash material, which is essential for fabricating accurate stone dies.
- 11. Base Plate Wax Spacer Polyethylene Wax Spacer Monzavi A, Siadat H. Use of wax spacers for putty-wash impression of implant snapon impression copings. J Prosthet Dent 2005;93:494.
- 12. Vacuum formed resin spacers Wu AY, Donovan TE. The use of vacuum-formed resin sheets as spacers for putty-wash impressions. J Prosthet Dent 2007;97:54-5.
- 13. Relieved putty impression Scalpel Flame bur Vented (2 holes to direct the wash) Leendert Boksman. The Hydraulic & Hydrophobic Impression Technique:Facts Based on the Research Literature
- 14. With the 1-step procedure , low viscosity impression material is injected around the prepared tooth or teeth then the putty impression material is immediately placed intra orally and the materials polymerize simultaneously. Simultaneous / Squash Technique Pameijer CH. A one-step putty-wash impression technique utilizing vinyl polysiloxanes. Quintessence Int Dent Dig. 1983 Aug;14(8):861-3.
- 15. • Accuracy of impressions resulting from the 1-step putty-wash technique is controversial.
- 16. • Some authors found that there was no difference in accuracy between techniques. Idris B, Houston F, Claffey N. Comparison of the dimensional accuracy of one- and two-step techniques with the use of putty/ wash addition silicone impression materials. J Prosthet Dent 1995;74:535-41.
- 17. Others criticized several potential disadvantages with this approach. Impossible to control the thickness of light body Usually portions of prepared margins are captured in the putty (putty materials are essentially deficient in their ability to record marginal details) Donovan TE, Chee WW. A review of contemporary impression materials & techniques . Dent Clin North Am 2004;48:445-70.
- 18. This article describes a modified 1-step putty-wash technique using vacuum-formed resin sheets as spacers to control the wash bulk and minimize the chance of unfavourable impression results. Using this technique, the limitations of using1-step putty-wash impression can be
- 19. PROCEDURE 1. Use the original diagnostic cast or cast recovered from an impression of the diagnostic provisional restorations to fabricate the vacuum-formed spacer
- 20. 2. Place the cast and a 5 x 5-inch sheet of 0.08-inch-thick soft clear ethyl vinyl acetate on a single-chambered vacuum-forming machine. Heat until a 0.5-inch droop develops, and then vacuum form the spacer on the cast.
- 21. 3. Do not prepare occlusal stops because they interfere with the removal of the spacer from the putty. • Trim the spacer to cover approximately 2 to 3 mm of marginal gingiva on the buccal and lingual surfaces of the teeth.
- 22. 4. Complete essential gingival retraction procedures on prepared teeth. 5. Place the vacuum-formed spacer intraorally and verify stability.
- 23. 6. Make a transfer impression of the spacer with high-viscosity putty impression material in a stock tray.
- 24. 7. Before the putty impression material is polymerized, remove the entire impression from the mouth and gently remove the spacer from the putty material.
- 25. 8. Simultaneously wash the putty tray with light-bodied polyvinyl siloxane impression material to make the definitive impression.
- 28. • Thickness of light body is controlled • Putty doesn't show up in critical areas • Decreased chair side time
- 29. Increased Laboratory time Additional material(resin sheets ) Adds Cost to the patient
- 32. Auto mix System Fewer Inherent voids Extended essential working time Reduce waste
- 33. Adhesion of impression material to tray All impression materials shrink slightly upon setting resulting in smaller die With proper tray adhesive (7 to 15 min), impression material shrinks towards the tray during setting resulting in slightly larger die which is preferable to a smaller one