Tutorial 2 - primary impressions Flashcards
what is the point in obtaining a primary impression?
There are 2 main reasons:
This is so that a primary denture can be designed for the patient.
As well as this, to ensure that correctly-extended special trays can be obstructed.
what things do we need in order to be able to take a primary impression?
examination kit
dentate stock trays - we shoukd bring a few sizes
mixing bowl, spatula, water measure.
adhesive and dappen pot
alginate
scalpel
gauze (wet) so that the impressions made of alginate don’t dry out.
putty to create impression of palate: putty also need for large edentulous areas ie saddles
disinfectant
ribbon wax to extend the tray or create a more accurate tray.
What is the purpose of the putty when creating primary dentures?
2 reasons:
to place on the palate - this will create a more accurate impression, especially if a patient has a high palate
to place in large edentulous areas - either bounded or distal-extension saddles
How can we modify impression trays for primary impressions?
Add ribbon wax to extend either distally of towards the buccal sulcus.
When taking a lower impression, where should we stand? What landmarks do we need to be aware of when taking this impression?
We need to ensure we are standing in FRONT of the patient.
then:
ensure patient’s mouth is half closed
ensure the frenal notch of the tray aligns with the labial frenum
seat the anterior part of the tray down so that the labial falange of the tray goes into the labial sulcus
ensure that the patient’s tongue does not get trapped beneath the lingual flange
Why ask a patient to stick theit tongue up when creating a denture?
helps reveal the contour of the floor of the mouth, the sublingual space, and the lingual frenum
after removing the PUTTY (not alginate) impression material from the patient’s mouth, what should we do?
we need to use the scalpel to trim 1-2mm off the rolled border, also removing undercuts.
we need to trim AWAY from the teeth to give 4mm clearance.
once impressions are finished, what should we do?
we should disinfect it, then wrap in WET gauze and place in a bag.
The wet gauze will prevent the alginate material from shrinking, as when it is exposed to air, it may shrink
where to stand when taking an upper impression>?
stand behind the patient and put the chair will be in a lower position
Some patients may start to gag whilst you are taking the impressions.
How will you manage this situation?
Calm and reassure the patient
Ask them to breathe through their nose
Sit the patient upright to minimise gagging
Distraction techniques - focus on something like wiggling their toes
Encourage saliva swallowing
Topical anaestehtic if available
The primary impression appointment is finished. What should you now tell the patient?
What you have achieved today
What is going to happen to their impressions
What is going to happen at their next visit
After the patient has left, what shall we do? There are 2 things.
Fill in an outcome form and lab prescription.
The lab prescription should include:
-Patient Details
-Your Details
-Today’s Date
-Date you need work back by (day before next appointment)
-Confirmation work has been disinfected
-Your teacher’s signature
-Your instructions: To cast the impressions then make special trays (specify what type) and wire-reinforced wax base and occlusal rims (for preliminary jaw reg)
PERFORATED:
Better retention as allows impression material to flow through and lock in place
Reduces distortion during setting and removal
Improved accuracy
NON-PERFORATED:
Can use adhesive to hold material in place
Prevents leakage of materials which are more runny
When there are minimal undercuts - eg when a pt is edentulous. Generally used when retention of the material is not a massive concern
