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Impression tray and impression technique

Impression tray and impression technique. Dr. Nora Sheta. Steps of Complete Denture Construction. IMPRESSION TRAYS AND IMPRESSION TECHNIQUES. IMPRESSION. An impression is a negative record or imprint of the tissues of the oral cavity that forms the basal seat of the denture.

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Impression tray and impression technique

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  1. Impression tray and impression technique Dr. Nora Sheta

  2. Steps of Complete Denture Construction

  3. IMPRESSION TRAYS AND IMPRESSION TECHNIQUES IMPRESSION An impression is a negative record or imprint of the tissues of the oral cavity that forms the basal seat of the denture. Reproduce a positive form and shape of the same oral tissues (Cast) .

  4. IMPRESSION TRAYS “A tray is an instrument used to carry the impression material to the mouth , holding it in position against tissues until the material hardens ,it helps in removing the impression from the mouth “. Parts 1 . Body Body 2 . Handle Body Handle Handle EDENTULOUS TRAY DENTULOUS TRAY Floor Flat Body Flange Long Dentulous Tray Handle Straight Floor Round Body Edentulous Tray Flange Short Handle L - Shape

  5. I- Stock trays II- Custom trays (Special, Individual trays) Types of Trays

  6. Impression tray • is composed of • Body: The body consists of a floor and flanges. • Handle.

  7. The body and handle are designed to suit different mouths 1-Dentulous mouth cases . 2-Edentulous mouth cases . 3-Partially edentulous mouth cases.

  8. types Stock tray • Perforated or non perforated • Metal or plastic

  9. Preliminary Impression USES Study cast As a study cast to study : 1. Ridge shape . 2. Palatal Vault shape . 3. Denture bearing areas . 4. Areas of undercut . 5. Relief areas . 6. Posterior palatal seal area . 7. Sharp bony edges . 8. Depth of the sulcus . 9. Inter-ridge space 10. Inter-ridge relations . As a cast on which the final impression tray is fabricated.

  10. SPECIAL OR INDIVIDUAL TRAYS TYPES • 1. Shellac base plates . • 2. Self & light curing acrylic resin . • 3. Cast or swaged metal . Advantages of Special Trays 1 . Fit more accurately the individual arch of the patient. 2 . Bulk of the impression material is reduced . 4 . More accurate border contour 5 . Less impression material is used . 6. More comfortable to the patient .

  11. Types of special trays 1- Shellac base plate special tray 2- Acrylic resin custom (special) trays: a- cold cured b- heat cured c- light cured Both heat and cold cured are used widely now. It is rigid and light in weight, not wrap in the mouth . 3- Cast or swaged metal tray 4- Vacuum formed plastic sheets It needs a pressure forming machine

  12. Comparison between shellac and acrylic resin custom trays Self-cured acrylic resin special tray • Shellac base plate special tray • Low strength. 2. Easily distorted by load and temperature. 3. Improper adaptation to the cast 4. Easily constructed • Higher strength and rigidity. • Not distorted by temperature. • Well adapted • 4. Easily constructed

  13. 1- with a spacer 2- without a spacer Tray can be

  14. “ One thickness of modeling wax or shellac base plate adapted on the study cast under the special tray “ SHIM OR SPACER

  15. Upper & Lower spacer (Shim)

  16. Custom (Special) trays with spacer (Shim)Steps for fabrication upper tray

  17. Custom Tray With Spacer

  18. Custom (Special) trays with spacer (Shim)Steps for fabrication lower tray

  19. 1 2 3

  20. 4 5 6 7

  21. 8 9

  22. FINAL IMPRESSION TECHNIQUES OR THEORIES 1 . Minimal Pressure Impression Technique (Mucostatic Impression Technique) . 2 . Definite Pressure Impression Technique or Mucocompression Impression or Functional Impression Technique . 3 . Selective Pressure Impression Technique .

  23. 2NDRY IMPRESSION TECHNIQUES

  24. CLINICAL 5 Final Impression . Upper Impression Lower Impression

  25. An impression is boxed to preserve the borders of the impression so that it will be accurately reproduced in the cast. Boxing the impression

  26. 1- Wax method 2- Plaster and Pumice method Methods for boxing

  27. Beading wax for boxing1- Wax Method

  28. 1-wax method

  29. 1-wax methodLower impression

  30. 2-Plaster and Pumice method Plaster and pumice for boxing

  31. 2-Plaster and Pumice methodUpper impression

  32. BOXING

  33. ADVANTAGES OF BOXING 1 . The borders of the impression are preserved 2 . The thickness of the base of the cast can be controlled 3 . Permits vibrating the stone material into the impression 4 . Time is conserved 5 . Material are conserved MASTER CASTS

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