Tutorial 4 - Tooth prep + secondary impressions Flashcards
Partial denture clinical stages?
TIP
For special trays it is very important to capture:
- Sulcus
- FES
RETENTIVE
RECIPROCAL
- drilling for rest seats
- adding composite or removing enamel to create an undercut
- guide planes
What tooth preparations may be required?
What are the arms of a c clasp?
Where are each placed? (See pic in answer )
- to provide support
- so occlusion doesn’t change
TIP
- any necessary tooth preparations need to be done BEFORE making the impressions
- OTHERWISE the impression taken would be wrong and can cause the denture to not fit
EXTRA
- to ensure that occlusion isn’t changed (EG by rest seat placement)
- to ensure an undercut is present where the clasp is placed SO that the denture is retentive
- make guide planes
What materials do you need to get out for this appointment?
- alginate or medium body silicone
- specific adhesive
- perforated or non perforated treat
- border moulding
When you place the tray it should be :
Border moulding
What is it?
Why is it done?
What material is used to border mould?
1
It is capturing active movement of the patient and active muscle attachment
Shaping of the border areas of an impression tray / shaping of impression material by manipulation or action of tissues adjacent to border of impression
Eg ask patient to push out tongue, raise tongue to upper lip and move it side to side
2
Done to:
- allows muscles to be captured
- to get the whole sulcus
- (allows impression materials to flow)
- ensures extension is correct
3
Material = Green stick compound - it is a high viscosity material
Trays
What trays do we use for alginate?
Wear trays do we use for silicon?
Alginate for perforated
Silicon is non perforated
- Non perforated
◦ can put pressure and compress the mucosa - mucocompressive therefore records shape of mucosa when it is under load
◦ can put pressure on the mucosa (mainly for free end saddle)- because so when patient bites down the tissue is already compressed , people have different thickness of mucosa, want to make sure when pt bites down on denture, the denture doesn’t rebound, want to make sure the denture is already compressed
◦ Mucocompressive can come from material or tray
Slide 14 - extra info
What trays are used for secondary impressions?
What neg may occur if tray is over or under extended
Discuss the case in detail with your teacher before proceeding
Before undertaking tooth preparations what must you do?
Once you are ready to start making your impressions remember:
Why is an accurate impression of the lingual sulcus vital when making a lower partial denture?
To allow for Maximum retention
To know whether to use a lingual bar or lingual plate
If you don’t have enough space you would have to use a lingual plate - if you have less than 6mm
“Please construct a wax base and occlusal rims to design drawn”
Similarly, you will need to draw the design neatly on the prescription card and ask your teacher to sign it
(Pic from Google )
What will you be doing at the next clinical stage?
