Impression Trays (PPT).pptx
- 1. Impression Trays DR SRINIVAS REDDY MDS DEPT OF PROSTHODONTICS NAVODAYA DENTAL COLLEGE
- 2. Definition is a device used to carry, confine & control the impression material from the patient's mouth. During impression making the tray facilitate insertion & removal of impression material from the patient's mouth.
- 3. Requirements Of Impression Trays 1. The tray should be rigid and strong but not too thick. 2. The tray should simulate the finished denture in size and shape. 3. The border extension of the tray should be 2mm short of the vestibular depth with no interference with muscle or frenal attachment. 4. The entire borders of the tray should be smooth and rounded. 5. The tray should retain its shape throughout the impression procedure and pouring of impression. 6. The handle of the tray should be angulated.
- 5. Types of Impression Trays Impression trays can be of various types: 🠶 1. According to the material used to fabricate the trays: a. Metallic trays (stainless steel, Aluminum) b. Non-metallic trays (plastic trays, acrylic resin trays)
- 6. 1. According to the method of fabrication of trays: 🠶 A. Stock trays: - Full arch trays - Sectional trays - Quadrant trays 🠶 B. Custom trays or Special trays
- 7. 3. According to the teeth present /absent in mouth: a. Edentulous trays b. Dentulous trays
- 8. How can I identify between Dentulous and Edentulous trays? Dentulous Trays – SquareCross-SectionFor patientswithteeth! Edentulous Trays – RoundedCross-Section For patientswithout teeth!
- 9. 4. According to the method of interlocking of material: a. Perforated trays b. Non-perforated trays c. Rim-lock trays i. Water-cooled ii. Non water-cooled
- 10. What is the difference between Stock trays and Custom trays? 🠶 STOCK TRAYS- Stock trays are ready-made and comes in specific sizes. Sostocktrays must be selected for best fit. They are re-useable after sterilization. 🠶 CUSTOM TRAYS Custom trays are fabricated on the particular patient’s cast thereby making it unique to the patient. This is why custom trays always are a better fit than stock trays. They are useful only for the particular patient- then discarded.
- 11. Stock Trays
- 12. Definition Impression tray that serve to carry the impression material to the mouth & support it in the correct position while it is hardening. This type of the trays can be used for several patients & used for making primary impression. They are made of different materials such as Al, Tin, Brass or Plastic, in variety of shapes, size to fit different mouth.
- 13. Factors effect in selection of stock tray: 1- The type of material used in the primary impression procedure. e.g. impression compound we used non-perforated tray, because it will be stick on the tray. And if we use alginate material we should use perforated stock tray. 2- Size of the arch. 3- Form of the arch. (round , square , taper ). 4- The stock tray must covered all the anatomical landmarks needed in complete denture & this is a most important point. 5- Stock tray should give a sufficient space to impression material in all direction.
- 14. Metal Trays Properties • Provide maximum support for impressionmaterials •Rigid •Durable and long lasting •Can be perforated or solid •Can be used with all elastometric materials
- 16. Plastic Trays Properties • Disposable • Eliminate cross-contamination • Can be modified • Rigid,thick walls to provide lateral support for the tray impression material to prevent distortion when pouring the model
- 18. What type of stock tray should I use? Stock Trays are always selected to the best fit. This selection is based on - 🠶 The type of mouth you want to make an impression of- 🠶 Dentulous Mouth – use DentulousTrays. 🠶 Edentulous – use EdentulousTrays. 🠶 Partially Edentulous – use CombinationTrays. 🠶 Type of impression material you want to use. 🠶 Elastic Impression Materials – generally use Perforated trays. 🠶 Inelastic materials – generally use Non-Perforatedtrays.
- 19. Custom Trays
- 20. Definition An individualized impression tray made from a cast recovered from primary impression. It is used in making a final impression. Primary Impression Preliminary Cast Special Tray Final Impression
- 21. Advantages of special trays: 1- Economy in impression material ( used less impression material required in special tray). 2- More accurate impression. 3Special tray provides even thickness of impression material. This minimize tissue displacement & dimensional changes of impression material. 4 The work with special tray is more easier & quicker than modifying stock tray to provide accurate impression. 5Special tray is more accurately adapted to the oral vestibules, this helps in better retention of denture. 6 Special tray are less bulky than stock tray which is more comfortable for the patient.
- 22. Materials used for construction of special tray: Non-Metallic Metallic Cast or Swaged Metal (Time Consuming) (Not popularly used) Resin 1. Cold cure acrylic resin 2. Hot resin crylic 3. Light cure acrylic resin Thermoplastic Material 1. Shellac base plate 2. Impression compound
- 23. Types of Custom Tray 🠶Close-fit Tray 🠶Tray with spacer and stop SPACER (WAX) (Openings in the wax where acrylic will flow in to form stops)
- 24. Sterilizing trays 🠶 Trays should be cleaned properly and sterilized before use 🠶 Disposable trays are recommended 🠶 Sterilization can be achieved by autoclaving, dry heat or chemical vapors
- 25. Thank You