1/9: Preliminary Impressions for Edentulous Patients

Question 1

What are examples of inelastic or rigid impression materials?

Answer 1

Plaster
Zinc-oxide-eugenol
Impression compound
Wax

Question 2

What are examples of elastic (elastomers, elastomeric) impression materials?

Answer 2

Hydrocolloids
Polysulfides
Polyethers
Silicones

Question 3

What are examples of irreversible hydrocolloid?

Answer 3

Alginate
Salts of alganic acid
Diatomaceous earth
Cacium sulfate
Potassium alginate
Zinc oxide
Potassium titanium fluoride
Sodium phosphate

Question 4

What material has the highest percent of irreversible hydrocolloid?

Answer 4

Diatomaceous earth

Question 5

What are examples of reactors that are irreversible hydrocolloid?

Answer 5

Calcium sulfate
Potassium alginate

Question 6

What is an example of an irreversible hydrocolloid that influences setting time?

Answer 6

Zinc oxide

Question 7

What is an example of an irreversible hydrocolloid that ensures a dense, hard stone cast surface?

Answer 7

Potassium titanium fluoride

Question 8

What is an example of an irreversible hydrocolloid that is a retarder?

Answer 8

Sodium phosphate

Question 9

What is a filler which increases strength and stiffness and produces a smooth texture?

Answer 9

Diatomaceous earth

Question 10

What are the two types of impression trays?

Answer 10

Stock and custom

Question 11

What kind of impression tray varies in sizes and materials?

Answer 11

Stock

Question 12

What kind of impression tray is fabricated on a patient’s cast?

Answer 12

Custom

Question 13

What should you add to the periphery of the stock trays prior to the impression?

Answer 13

Rope wax

Question 14

What are the steps of taking a max. alginate impression?

Answer 14

1. Size correct tray; modify borders with wax if needed
2. Have patient wipe palate with gauze to remove viscous saliva
3. mix thoroughly - 45 sex
4. load tray and set aside
5. preload palatal vault with material
6. Seat imp. tray while retracting lips/cheeks to prevent trapping air in vestibules
7. hold tray very still in mouth approx. 3 minutes
8. remove in one firm motion
9. inspect, rinse, disinfect with contact
   time = 10 minutes
   rinse before pouring

Question 15

What are 7 things the max. preliminary impression should include?

Answer 15

1. Residual ridge
2. buccal and labial vestibules
3. frenal attachments
4. fovea palatinae and vibrating line
5. palate
6. tuberosities
7. hamular notches

Question 16

What are the steps of taking a mandibular alginate impression?

Answer 16

1. Patient upright position
2. Size tray; add wax to border if needed
3. Powder and room temperature water
4. mix, load tray, set aside
5. Preload buccal vestibule
6. Partially seat tray in mouth, patient lifts and protrudes tongue slightly, seat tray further
7. Have patient close about half way. Pull lip out slightly to free trapped air
8. Seat and hold tray for 3 minutes. Remove, inspect, rinse, disinfect

Question 17

What are 8 things the max. preliminary impression should include?

Answer 17

1. Residual ridge
2. Retromolar pads
3. Buccal shelf areas
4. External oblique ridges
5. Frenal attachments
6. tuberosities
7. hamular notches
8. Retromylohyoid spaces
9. Alveololingual sulcus
10. Labial and buccal vestibules