Primary impressions and registration Flashcards
What are the steps to primary impressions
Personal Protective Equipment
Tray Selection and Try in
Select an Impression Material
Take the Impression
Decontamination
Laboratory Card
Why do we need primary casts
Denture design
-saddles
-occlusion
-undercuts
Lab
-make primary models
-construction of special trays/primary bite blocks
How are impressions taken with free-end saddles
Record free end saddle areas using compound.
Then apply alginate adhesive to tray and compound
Apply alginate to wash over compound to fill the tray
How are impressions decontaminated
Rinse
Place in Perform for 10 minutes
Indicate that impressions have been decontaminated on lab card
Bag with wet cotton wool or paper towel and take to lab as soon as possible
What are teeth which contact every time in occlusion called
“index teeth”
What are casts mounted on
articular
What happens if your casts cant be hand articulated
You need primary record blocks
Upper shellac baseplate
Lower wire strengthener
How is primary registration recorded
Bring blocks to required occlusal level
Add bite registration paste and ask the patient to occlude
Check index teeth are still in contact
Why might teeth not be in contact after adding bite registration paste in primary registration
Not enough wax removed from block
Too much registration paste used
Bite registration paste set before the patient could occlude
What should be done before taking master impressions
Design the denture
Identify any teeth that may require modification eg rest seats/guide planes
If planning a CoCr denture ask the lab to survey your primary casts and, following your primary jaw registration (if needed), mount on articulator and return to you along with special trays
You can now design your denture prior to taking the master impression
