impression tray and impression technique

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Impression tray and Impression tray and impression technique impression technique Dr. Nora Sheta

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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. - PowerPoint PPT Presentation

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Page 1: Impression tray and impression technique

Impression tray and Impression tray and impression technique impression technique

Dr. Nora Sheta

Page 2: Impression tray and impression technique

Clinical Laboratory

1. Examination & Diagnosis

2. Primary impression Study cast Special tray

3. Final impression Boxing and pouring master cast Occlusion blocks

4a. Jaw relation registration

4b. Selection of artificial teeth

Mounting on articulator Setting of artificial teeth and waxing up

5. Try in Processing

6. Insertion

7. Post insertion care

Page 3: Impression tray and impression technique

IMPRESSION TRAYS AND IMPRESSIONTECHNIQUES

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) .

Page 4: Impression tray and impression technique

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

2 . Handle Body Body

Handle Handle

DENTULOUS TRAY EDENTULOUS TRAY

Dentulous Tray

Edentulous Tray

Body

Handle

Body

Handle

Floor

Flange

Floor

Flange

Straight

L - Shape

Flat

Long

Round

Short

Page 5: Impression tray and impression technique

Types of TraysTypes of Trays

I- Stock trays

II- Custom trays (Special, Individual trays)

Page 6: Impression tray and impression technique

Impression trayImpression tray

is composed ofBody: The body

consists of a floor and flanges.

Handle.

Page 7: Impression tray and impression technique

The body and handle are designed The body and handle are designed to suit different mouths to suit different mouths

1-Dentulous mouth cases

.

2-Edentulous mouth cases

.

3-Partially edentulous mouth cases.

Page 8: Impression tray and impression technique

types Stock traytypes Stock tray

Perforated or non

perforated Metal or plastic

Page 9: Impression tray and impression technique

Preliminary Impression

Study cast

USES

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.

Page 10: Impression tray and impression technique
Page 11: Impression tray and impression technique

SPECIAL OR INDIVIDUAL TRAYS

1. Shellac base plates .

2. Self & light curing acrylic resin .

3. Cast or swaged metal .

TYPES

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 .

Page 12: Impression tray and impression technique

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

Page 13: Impression tray and impression technique

Comparison between shellac Comparison between shellac and acrylic resin custom traysand acrylic resin custom trays

• Shellac base plate special tray

1. Low strength.2. Easily distorted by load

and temperature.3. Improper adaptation to

the cast4. Easily constructed

Self-cured acrylic resin special tray

1. Higher strength and rigidity.2. Not distorted by temperature.

3. Well adapted

4. Easily constructed

Page 14: Impression tray and impression technique

Tray can beTray can be

1- with a spacer

2- without a spacer

Page 15: Impression tray and impression technique

SHIM OR SPACER SHIM OR SPACER

“ One thickness of modeling wax or shellac base plate adapted on the study cast under the special tray “

Page 16: Impression tray and impression technique

Upper & Lower spacer (Shim) Upper & Lower spacer (Shim)

Page 17: Impression tray and impression technique

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

Page 18: Impression tray and impression technique

Custom Tray With SpacerCustom Tray With Spacer

Page 19: Impression tray and impression technique

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

Page 20: Impression tray and impression technique

1

2 3

Page 21: Impression tray and impression technique

4 5

6 7

Page 22: Impression tray and impression technique

8

9

Page 23: Impression tray and impression technique

FINAL IMPRESSION TECHNIQUES FINAL IMPRESSION TECHNIQUES OR THEORIES 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 .

Page 24: Impression tray and impression technique

(1) IMPRESSION TECHNIQUE

MINIMAL PRESSURE ( MUCOSTATIC)

FUNCTIONAL PRESSURE (MUCOCOMPRESSIVE) SELECTIVE PRESSURE

(2) PHILOSOPHY ALL THE TISSUES ARE UNDER THE LEAST PRESSURE.

ALL THE TISSUES ARE UNDER FUNCTIONAL PRESSURE.

TISSUES THAT CAN WITHSTAND PRESSURE ARE LOADED. AND TISSUES THAT CAN'T ARE RELIEVED.

(3) TRAY PERFORATED + ON SPACER + WITH TISSUE STOPS.

WELL ADAPTED + NO SPACER + WAXRIM.

STOCK TRAY WITH COMPOUND ,THEN IT IS RELIEVED AND WASHED WITH PLASTER IMPRESSION MATERIAL.

(4) PRESSURE FINGER PRESSURE PATIENTS BITING FORCE. FINGER PRESSURE.

(5) IMPRESSION MATERIAL PLASTER, FLOWY MATERIAL. ZnO/E , HEAVY MATERIAL IMPRESSION COMPOUND (HEAVY)+ PLASTER OR ZnO/E(FLOWY)

2NDRY IMPRESSION TECHNIQUES

Page 25: Impression tray and impression technique

CLINICAL

5 Final Impression .

Upper Impression

Lower Impression

Page 26: Impression tray and impression technique

Boxing the impressionBoxing the impression An impression is boxed to preserve

the borders of the impression so that it will be accurately reproduced in the cast.

Page 27: Impression tray and impression technique

Methods for boxingMethods for boxing

1- Wax method

2- Plaster and Pumice method

Page 28: Impression tray and impression technique

Beading wax for boxingBeading wax for boxing

1- Wax Method1- Wax Method

Page 29: Impression tray and impression technique

1-wax method1-wax method

Page 30: Impression tray and impression technique

1-wax method1-wax method Lower impressionLower impression

Page 31: Impression tray and impression technique

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

Page 32: Impression tray and impression technique

2-Plaster and Pumice method2-Plaster and Pumice methodUpper impressionUpper impression

Page 33: Impression tray and impression technique

BOXING

Page 34: Impression tray and impression technique
Page 35: Impression tray and impression technique

MASTER CASTS

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