Impression trays are devices used to carry, confine, and control impression material in the mouth. There are two main types: special trays which are custom-made for individual patients and used for final impressions, and stock trays which come in various pre-formed sizes and shapes and are used for primary impressions. Impression trays must be rigid, dimensionally stable, smooth, and able to support the set impression material when removed from the mouth. They are classified based on their fabrication method, arch, presence of teeth, and materials used.

2. IMPRESSION
TRAYS

3. IMPRESSION TRAYS:
*Also called "DENTAL TRAY".
• Definition:
It is a device used to carry , confine and control the
impression material from the patient mouth..
Purpose:
*To give rigid support to the impression material.
*Facilitate the introduction of impression material to the
mouth.

4. Parts of Tray:

5. Required properties of Tray:
*Must be rigid.
*Dimensionally stable.
*Should be smooth.
*Should not distort tissue at vestibular.
*Should support set impression material
when removed from mouth.

6. Types of Impression Trays:
• There are two main types of Impression trays;
•1-Special tray.
•2- Stock tray.

7. 1-Special Tray:
Also called "custom tray".
• It can be used only for one person.
• Used for final impression.

8. 2-Stock Trays:
• Also called pre-formed Tray.
• It can be used for many patients.
• Used for Primary impression.

9. Size and Shape of Stock Trays:
*Can be of different size
and shape..
1-Full tray:
2-Quadrant tray:
3-Sectional tray:

10. 3-Upper Arch Tray;
Palatine part vault
4-Lower Arch Tray;
No palatine part

11. Materials Used for Fabrication
Of Stock Trays:
1-Metal Trays:
2-Plastic Trays:

12. Classification of
Dental Trays::

13. Classification on The Basis of
Fabrication:
*Two types;
1-Perforated:
2-Non-Perforated:

14. Types on the basis of
individualized
1-Close Fitting:
2-Lose Fitting:
Space Special Tray

15. On the Basis of lower and
Upper Arch:
•1- Upper Arch Trays
•2- Lower Arch Trays

16. On the Basis of presence of
Teeth:
*Two Types;
1-Edentulous trays.
2-Dentulous Trays.

17. 1-Edentulous Trays:
• Used for edentulous patients..
*small flanges.
*Narrow floor.
*Over floor.

18. 2-Dentulous Trays:
• Used for dentate patients.
*Long Flanges.
*Wide floor.
*Flate floor.

19. Difference between Dentulous and
Edentulous Trays:

20. On The Basis Of Materials:
1-Metallic:
2-Non-Metallic:
Plastic

21. Advantages of Using Impression
Trays:
Disadvantages Of Impression
Trays: