Define primary impressions.
a - likeness/ imprint pf teeth/ edentulous areas
what is the + replica of an impression
cast
Classify impression based on impression making techniques
- mucostatic
- mucocompressive
- selective pressure
what is the mucostatic impression technique based on?
pascal’s law
thin film of saliva on mucous membrane acts as a seal
materials used for mucocompressive technique
- impression compound
- waxes
- soft liners
Define Selective pressure technique
impression extends on denture bearing area
does not disturb limiting structures
What is a record block?
trays with occlusal rims used to record impression in closed mouth technique
How to select a stock tray for primary impression
- 5mm clearance b/w tray nf ridge
- handle of tray extend of tuberosity nd hamular notch
extension of custom tray to record 2` impression
2 mm short of peripheral structers
how is 2` impression recorded
border moulding
T/F: disinfect the impression under running water
F
results in distortion. use a disinfectant. eg : iodophor: immerse for 10 minz
steps to be taken to avoid shrinkage of impression
place in slurry water
T/F: A cast must be poured as soon as the impression is taken
F
The cast should be poured within 15 minutes after impression making otherwise dimensional changes will happen.
Min thickness of a base of a cast
min 10 mm
how is a cast poured?
using the 3 pour technique
parts of a cast
- base
- anatomical surface
- Land area
steps to follow before using a model trimmer
Before using the model trimmer, the cast should be soaked in slurry water for 5 minutes.
width of the land area of the cast
3 mm
