Impressions

Question 1

what are impressions

Answer 1

the negative of a patients mouth that are used to create a replica of their dentition

Question 2

guidelines for tray selection

Answer 2

should fit comfortably
should extend slightly beyond facial surfaces of teeth and beyond alveolar process
should extend 2-3 mm beyond most posterior tooth in arch
2-3mm of depth beyond occlusal surface
add wax to customize
ensure minimal trauma

Question 3

working time

Answer 3

time needed to mix alginate, load tray and seat in mouth

Question 4

setting time

Answer 4

time required for alginate to fully set/gel

Question 5

regular set

Answer 5

working time 2min
setting time 4.5 min

Question 6

fast set

Answer 6

working time 1.25min
setting time 1-2min

Question 7

colour change alginate

Answer 7

purple when mixed with water
pink when time to load
white when set

Question 8

temperature and setting time

Answer 8

altering the temp of water can control working and setting time
colder: increases
warmer: decreases

Question 9

taking a mandibular impression

Answer 9

4 minutes
occlusal plane parallel with floor
operator at 8 o’clock position

Question 10

taking a maxillary impression

Answer 10

4 minutes
occlusal plane parallel with the floor
operator at 11 o’clock

Question 11

gag reflex is located

Answer 11

on the posterior portion of the tongue and soft palate

Question 12

tips to minimize gagging

Answer 12

seat max tray from posterior to anterior
use wax on posterior max tray
avoid overfilling tray
HurriCaine spray
seat patient upright
breath through nose

Question 13

what makes a good impression

Answer 13

no voids, tears or debris
clear detail
all teeth and alveolar process
retromolar area or max tuberosity
alignate material firmly attached to tray
adequate peripheral roll

Question 14

dental cast

Answer 14

a 3D model of the teeth and surrounding tissue of both arches that is created from the impression

Question 15

casts have two parts

Answer 15

anatomic and art portion

Question 16

dental cast is used for

Answer 16

tx planning, tracking of tx progress, patient ed, construction of custom-made oral appliances

Question 17

dental cast material

Answer 17

gypsum

Question 18

pouring models

Answer 18

when stone is a creamy mixture it is ready to pour
place on lab vibrator to release bubbles
place impression on vibrator
mixture should flow

Question 19

pouring models mixture flow

Answer 19

mixture should flow into impression starting at distal end of most posterior tooth

Question 20

making a base

Answer 20

mound remaining mixture up, approx. 2x2 inches wide and 1 inch thick

Question 21

trimming

Answer 21

maxillary is pointed
mandibular is rounded