Lecture 1 (Alginate Impressions)

what is the purpose of the impression tray

it is a device that is used to confine, carry, and control the impressional material while making an impression

how does water temperature affect setting time of alginate

warmer = faster

colder = slower

how does working time affect setting time of alginate

adding water will increase your working time

how does the water:powder ration affect setting time

more water, less powder = slower

less water, more powder = faster

what is the first stage of taking an alginate impression (prep)

1. select tray size and check fit

2. adapt rope wax as needed

3. apply adhesive and let dry

what is the second stage of taking an alginate impression (making alginate)

4. fluff alginate powder

5. scoop powder and tap to remove voids

6. level powder with spatula

7. measure water to powder

8. mix contents by putting water in first, then powder and mix until creamy (1 min)

what is the third stage of taking an alginate impression (taking the impression)

9. load the alginate contents into the tray

10. insert the tray and hold immovable for 3 mins

11. break seal and snap the impression out of the mouth]

12. rinse impression and pour within 12 mins (or put in ziplock and pour within an hour)

how to prevent voids

prevent by loading tray without too much force and by mixing correctly

how to prevent an off-centered tray

prevent by repositioning tray, and ensure there is even force distribution

how to prevent a shallow vestible

prevent by choosing the correct tray size and placing enough force when loading tray

shallow vestible = not enough material extending past the gingival margin