1st Session: Clinical Alginate Impressions Flashcards
Define study models:
The positive reproduction of the oral cavity, used to aid in diagnosis and treatment planning.
What is alginate?
An elastic, irreversible hydrocolloid impression material.
Benefits: simple and cost effective.
How close should the tray be to the vestibule?
2 mm from the vestibule.
What is the vestibule?
The border at the lips/cheeks and gingiva: the muco-buccal fold.
How do you modify a tray to fit better?
Wax, compound, heavy body silicone
How do you prepare the mouth for alginate?
- Try in tray
- Dry the occlusal surfaces with air
- OK to use mouthwash
- Don’t take too many impressions - the alginate will begin to stick to teeth.
Why wet the rubber bowl before mixing the alginate?
Wet to fill in the micropores - helps keep the proper water powder ratio. (Not necessary when using disposable bowl).
What order do you add the alginate powder and water?
Add the alginate powder TO the water.
What is the working time and setting time for alginate?
Working time: 1-2 minutes.
Setting time: 2 - 4 minutes
What does an ideal alginate impression look like?
Excellent occlusion, no bubbles, good rounded muco-buccal fold.
What happens if the tray is rocked or wiggled to remove it?
Can create overall distortion of the impression.
How are the trays disinfected?
Rinse with water for 30 seconds.
Spray ProSpray
Rinse with water for another 30 seconds
How long can you wait to pour the impression?
Only 30 minutes to prevent distortion! Keep damp in bag with wet paper towel.
What is the material used to pour an impression?
Microstone.
How large should the base of the cast be?
About 8-10 mm, or 2/3 of the cast. Trim about 2-3 mm away from anything anatomical.
