Tutorial 2 - RPD primary impressions Flashcards
https://keats.kcl.ac.uk/mod/kalvidres/view.php?id=7424852
why do we make primary casts before making dentures?
1) A partial denture can be designed for the patient
2) Correctly extended special trays can be constructed
- important so have cast to see how teeth come together
key things to do to ensure infection control?
- all lab work needs to be disinfected in perform bath for 10 minutes before and after any clinical procedure
- set up perform bath at start of session and empty at end
(can use patient bib on work surface incase of any spillages)
what equipment will you need to get out before starting treatment
TIPS for when inserting trays
- Use red ribbon wax - for older patients or those with delicate mucosa as can put to protect and make more comfortable
- Rotate the tray in to ensure you don’t hurt the patient, don’t just push in
- press down posterior part first then anterior to ensure excess impression material goes to the front, hence more comfortable for patient
tray selection
1
sizes of trays
2
anatomical landmarks that need to be covered?
1
- usu comes in 3 sizes
- small, medium, large
2
- make sure tray covers anatomical landmarks
- dentition present
- saddles (edentulous spaces)
- buccal + labial sulci
- maxillary tuberosities (if FES)
- maxillary hard palate
- mandibular buccal shelves, retromolar pad, retromylohyoid fossa (if FES)
How and why may you need to modify trays before using them on patients?
- Consider whether the trays need to be modified in any way
1) TRAY TOO SHORT
- can put red ribbon wax to extend the ends
- can use hot air instrument to push out periphery of tray and lengthen it slightly
2) TRAY TOO BIG
- cut tray slightly
- then put red ribbon wax on edges as will be sharp
what should you do prior to mixing the impression material?
- explain to patient that 2 stages to impression
- first is putty (a firmer impression material) and then alginate (a runnier impression material)
what part of a care plan should dentures be? why?
- usually last part of care plan
- designing denture is very specific and long, once made they are hard to alter
- so need to treat other problems first (EG. restorations), in case these alter the denture design
why do we take primary impressions of the lower and upper jaw, even if the patient only requires a denture for 1 arch?
- as this allows articulation of the upper and lower casts with the relevant anatomical structures
what are constructed after primary impressions?
(hint used for secondary impressions)
- special trays that are custom made for patient
- gives more accurate impression for patient
- ## as spacing between impression tray and the remaining teeth and edentulous areas are fairly constant
How to take a lower impression?
(split into smaller Q’s???)
PLACING PUTTY
- Mix putty + catalyst (wearing non-latex gloves) (
- Place putty in required area in tray
- Standing in front of the patient, rotate tray into position (with patient’s mouth half closed)
- Seat the posterior part of the tray, ensuring that the patient’s tongue does not get trapped beneath the lingual flange. Border mould the putty
- Once set, remove the tray then rinse
- Show your teacher before proceeding to the next stage
- Using the disposable scalpel (and wearing protective glasses) trim 1 to 2mm from the rolled border, remove undercuts and trim away any teeth impressions with about 4mm clearance
PLACING ALGINATE
- Apply alginate adhesive
- Assistant mixes alginate with water in correct ratio
- load alginate over putty + whole tray
- place tray in mouth as before (posterior to anterior, etc)
- undertake border moulding
- ask patient to protrude + raise tongue again to avoid overextension of lingual flange
- Once set, remove impression
- Rinse impression, carefully examine it then decide whether it is acceptable
- show to tutor
- Once impression has been approved, rinse to remove any debris and plaque
- disinfect (for 10 minutes) in perform bath then rinse
- wrap in damp gauze and sealed bag and label
why is it important for the patient to move their patients tongue while you do a lower impression?
- ensure it’s not trapped
- ask them to raise it up, protrude it and move it side to side slowly
- this will help activate muscles on floor of mouth
- and will help record a functional impression of the sulcus and not over extended lingually
- lifiting tongue will also ensure tongue is not trapped in lingual flange
What anatomical landmarks should align with what parts of the tray during a lower impression?
- Ensure that the frenal notch of the tray aligns with the labial frenum
- Seat the anterior part of the tray down so that the labial flange of the tray goes into the labial sulcus
How to take an upper impression?
PRETTY MUCH SAME ANSWER AS LOWER
- Similar to lower impression except you will need to stand behind the patient and so the chair will be in a lower position
- Putty will be needed in the palatal vault (make sure put adhesive here)
how to manage a gagging patient?
- often with upper arch
- important to not overfill impression tray ESPECIALLY POSTERIORLY
- Try to press back down first so excess material goes to the front
- try use a distraction technique
- EG tapping temple, wiggle toes, count in head ,etc)
- occasionally sick bowl needed
- May need to wait till fully set then take it out for patients with gagging reflex
- ask them to breathe through nose
removing alginate impression tips
- important to remove denture without distorting
- upper impression being removed
- releasing impression by using fingers at canine + premolar position
- supporting occlusal surface of tray anteriorly
what to do before discharging patient?
- primary jaw registration in next stage
what to do once patient has left
What information do you need to provide the laboratory?
NEED TO ANSWER THESE Q’S highlighted in red
