Taking an Alginate Impression

Question 1

When determining the amount of alginate material to be used it is best to follow the ______ _____ for the powder/liquid ratio.

Answer 1

manufacturer’s instructions

Question 2

The most often alginate powder to water ratio is _____ using a plastic scoop.

Answer 2

one-to-one

Question 3

Before scooping the alginate powder it is essential to _____ the container in order to ____ the alginate material.

Answer 3

tumble; fluff

Question 4

When making your scoops you will want to _____ the scoop and then ____ it off the spatula.

Answer 4

overfill; level

Question 5

One thing that you do not want to do is ____ ___ ____ ____ in the scoop.

Answer 5

pack the powder down

Question 6

The first thing you want to do when before mixing is ___ ____ into the bowl and then add ____.

Answer 6

add water; powder

Question 7

The two variables that will affect the setting time of the alginate is the _____ ____ and the _____ of the _____.

Answer 7

powder/liquid ratio; temperature of the water

Question 8

Water that is _____ will set faster and likewise _____ water will set slower.

Answer 8

warmer; cooler

Question 9

Mixing should be complete within ____. If you increase the mixing time the final product will be _____. If you decrease the mixing time the impression material will become ____.

Answer 9

one minute; stronger; weaker

Question 10

When mixing is complete the material should appear _____, _____, and free of _____.

Answer 10

smooth; glossy; air bubbles

Question 11

The removal of alginate is delayed _____ minutes after gelation.

Answer 11

2-3

Question 12

After the alginate impression has been made it must be _____.

Answer 12

disinfected

Question 13

The main contributor to the accuracy of the alginate impression is the _____, ______, or ______.

Answer 13

evaporation; syneresis; imbibition

Question 14

_____: swelling due to absorption of water

Answer 14

imbibition

Question 15

_______: After hydrocolloids have set they contract as they exude water

Answer 15

Syneresis

Question 16

When loading the mandibular tray, gather _____ of the material into the spatula and load ____ of the tray from lingual (or buccal) border and press the material ____ and forward. Repeat procedure on the opposing side of the tray.

Answer 16

one-half; one side; downward

Question 17

Alginate is acceptable for fabricating bridges, crowns, and inlays. Nearly all impression materials are acceptable for full-denture impressions.

a) The first statement is true. The seconds statement is false.
b) The first statement is false. The second statement is true.
c) Both statements are true.
d) both statements are false.

Answer 17

b) The first statement is false. The second statement is true.

Question 18

What error is in this impression?

a) The tray is too small
b) There is not enough alginate
c) Both a) and b) are possible arrors.
d) There is no error

Answer 18

c) Both a) and b) are possible arrors.
* Solution: Make sure there is wiggle room in the mouth with the chosen tray. Make sure there is enough alginate surrounding all teeth. The problem with this tray is that the alginate has not gone around the second molars*

Question 19

What error is in this impression?

a) Way too much alginate
b) The mixture has too much water
c) Not clearing out excess in back of the mouth
d) All of the above

Answer 19

d) All of the above

Solution: Use less alginate, check the water/powder ratio, and check to make sure the airway is clear.

Question 20

What error is in this impression?

a) Not enough alginate
b) Tray is too small
c) Not seated all the way
d) Material started to set
e) Did not move lip over edge of tray
f) all of the above

Answer 20

f) all of the above
* Solution: Fill the tray with enough alfinate, make sure to check tray size for movement, Seat tray until material oozes from lips, do not overmix, bring lip over front of tray.*

Question 21

What error is in this impression? (Two possible errors)

Answer 21

1. The adhesive was not used
2. The impression was not kept moist
   * Solution: Use adhesive. Disinfect and stor in moist baggie*

Question 22

What error is this impression?

a) Tray is too small
b) Tray was not centered
c) Impression was not seated all the way
d) Both b and c

Answer 22

d) Both b and c
* Solution: Center the tray as you insert into the mouth. Seat until the vestibules fill with alginate.*

Question 23

The ideal mix should look like this. It should be smooth and creamy Fills the tray without ____ ____ _____. The tray is not visible under the alginate.

Answer 23

going over edges

Question 24

The alginate should cover all teeth plus ___ beyond the cervical margin. Name four landmarks that should also be present.

Answer 24

1. All vestibules
2. Frena are present
3. Retromolar pads
4. Maxillary tuberosity
5. Edentulous ridges

Question 25

The proper seating of trays is from _____ to _____.

Answer 25

Posterior; anterior

Question 26

When removing trays, release the suction by placing finger on _____ ____ of the tray and push firmly down for maxillary (up for mandibular)

Answer 26

posterior edge

Question 27

The process for disinfecting the bite block is rinse with water at the sterilization sink, _____, wrap in paper towel, place in baggie.

Answer 27

spray with disinfectant

Question 28

Why would the double-pour technique be a preferred method of fabricating a cast/studymodel?

a) It is the quicker of the two
b) Prevents distortion of oral structures.
c) Produces a better reproduction of oral structures
d) It is a safer technique

Answer 28

b) Prevents distortion of oral structures.
* The first pour will have initially set before the second pour is done, which will help prevent distortion*