Frequently Asked Questions (FAQs)
1. What are the 3 C's of custom tray fabrication?
The 3 C's of custom tray fabrication are to carry, control, and confine the impression material. Custom-made trays made from acrylic or VLC resins are used in final impressions for crown and bridge restorations and denture construction.
2. What materials are needed for dental impression?
The four types of elastomeric impression materials commonly used are addition silicone (PVS), condensation silicone, polyether, and polysulfide. These materials come in different consistencies like putty, heavy body, medium body, and light body.
3. Why are there holes in impression trays?
The holes in impression trays allow the impression material to expand through them, securely holding it in place. This design is particularly useful for double-step impression techniques and elastomeric materials.
4. What are the basics of tray set up?
For tray set up, arrange the instruments on the tray in the order of use, from left to right. Group the instruments by their function and place cotton supplies across the top of the tray.
5. What are the ideal requirements of custom tray?
The ideal requirements of a custom tray include stability in air and moist environments, volume stability over time, moisture resistance, rigidity, adhesion of the impression material, and an even thickness of the impression material.
6. Which type of impression material requires special equipment to use?
Agar hydrocolloid impression material, also known as hydrocolloid, requires specific equipment for its use.
7. What are the three types of custom impressions trays and their use in dentistry?
The three types of custom impression trays are quadrant trays (covering half of the arch), section trays (suited for anterior teeth), and full arch trays (covering the complete arch). Each tray has its specific use in dentistry.
8. Can impression trays be reused?
While plastic trays are often single-use, some plastic varieties may be sterilized and reused. Stainless steel trays, on the other hand, are a sustainable option as they can be reused.
9. Should an impression tray be sufficiently deep?
An impression tray should be sufficiently deep to allow 2 to 3 mm of material between the tray and the incisal or occlusal edges of the teeth. It should also extend approximately 2 to 3 mm beyond the third molar, retromolar, or tuberosity area of the arch.