Impressions of the upper and lower arch

Question 1

Alginate impressions must be cast within

Answer 1

24 hours

Question 2

Alginate should not be soaked in water because

Answer 2

Absorbs it and alters form

Question 3

Impression taking procedure steps

Answer 3

-Selection of tray
-Mixing of material
-Placement of tray in mouth
-Shaping of borders of impression
-Removal of tray

Question 4

Trays used in orthodontic impressions

Answer 4

Orthodontic impression trays

Question 5

Movements that should be possible after tray insertion

Answer 5

Lateral movements

Question 6

Tray can be extended with

Answer 6

Modelling wax

Question 7

Orthodontic trays are normally

Answer 7

Perforated

Question 8

If non perforated ortho trays are used

Answer 8

-Overlaid with leukoplast tape or adhesive

Question 9

Position for maxillary impressions

Answer 9

Behind or side of patient

Question 10

Pressing of tray in Maxilla

Answer 10

Back to front

Question 11

Position for mandibular impressions

Answer 11

Infront of patient

Question 12

Pressing of tray in mandible

Answer 12

Front to back

Question 13

Complications during impression taking

Answer 13

-Gap reflex
-Material in hypopharynx
-Aspiration of material

Question 14

Methods to avoid complications

Answer 14

-Upright patient position
-Mixture not liquid or excessive

Question 15

Adjunct for patients with gag reflex

Answer 15

Topical anaesthetic(cream or ointment) in area of incisive papilla

Question 16

Use of first plaster model

Answer 16

Study model for:
Biometric measurements, Appliance planning and tracing
Appliance fabrication

Question 17

Use of second plaster model

Answer 17

-Orthodontic documentation
-Remains at orthodontist