DENTURES3 Flashcards
What are the objectives of the registration stage?
Define shape of maxillary rim
Determine occlusal plane
Define position of the lower teeth
Determine jaw relationship
Select shade and mould
What equipment is used to trim adjust wax block?
Willis bite gauge
Pallet knife
Hot plate
Bunsen
What are the steps in adjusting the upper record block?
Adjust upper block for retention, then tooth position, then occlusal plane
What are the steps in adjusting the record block to maximise retention?
Try it in- usually bulky
Any overextension of peripheries or too much lip support will cause it to drop
Use tools to make adjustments (sometimes requires labial/buccal adjustments)
What should you use and consider when adjusting the upper block for tooth position?
Old dentures- how much tooth they show
Patients age
What should be checked when adjusting upper record blocks for tooth position?
Lip Support Incisal Level Midline Buccal corridor Occlusal plane
How is lip support ascertained?
Looking at the nasiolabial angle from side on- should be around 90 degrees
What can be done to check the incised plane level?
Look at where it is with current denture
Old photos (caution)
Ask patient to say fricatives
What factors can cause incised plane level to vary?
Age
Lip level
What is the issue with showing more tooth?
Can compromise stability of denture
What should be done before trimming the block to finalise position of anteriors?
Get patient to lick lips and relax
Saying fricatives
What should be done before trimming the block to finalise position of anteriors?
Get patient to lick lips and relax
Saying fricatives
What should the incisal bite plane be parallel to ideally?
Interpupillary line
Where should the upper anterior teeth be positioned?
Incisors- up to 1cm anterior to incisive papilla
Canines- below nose
What is used to prescribe tooth position in different types of dentures?
Replica- look at treatment plan
Conventional- standard values
What does marking the lip line on the block help decide?
Height of teeth
How should the midline be marked on a record block?
Use mirror and stand behind patient
What is the starting point of the buccal corridor?
Mid-canine line (canthus of eye to canine area)
What arch has a narrow buccal corridor?
Broad arch
What does the width of the buccal corridor determine?
How much tooth fills space
What should the occlusal plane be parallel to?
Ala-tragus line (or angled slightly up)
What are the steps in adjusting the lower record block?
Measure vertical dimension and establish face height
Lower tooth position
Registration
Why is lower teeth position critical?
Prevents loose feeling
What is the neutral zone?
Area with minimum force acting upon denture
What can happen if teeth are too lingually placed?
Can impact tongue
Where should lower teeth be positioned?
Anterior- on ridge (or slightly further forward)
Posterior teeth- on ridge
Why should the tongue be utilised in lower denture retention?
To hold denture down (Triangular shape of polished surface aids this)
What are the options for relationship of the upper and lower anteriors in a denture?
Shallow overbite
Overjet- anywhere from edge to edge to class 2
What are the options for relationship between upper and lower posteriors in a denture?
Normal
Crossbite
Why are cross bite relationships often chosen for posteriors in dentures?
This occurs when teeth are set on the ridges, means that posteriors don’t impinge on buccal corridor
What instruments are used to measure OVD and face height?
Willis bite gauge
Dividers
How is resting vertical dimension measured?
Place dots on point of nose and chin
Ask patient to moisten lips, say ‘m’ and bring them into light contact with adjusted rims in situ
How is OVD measured
Insert upper and lower blocks
Reduce the LOWER wax rim in height until it contacts upper rim evenly
What should the difference between RVD and OVD be?
OVD should be 2-4mm less than RVD (often greater with worn teeth)
Avoid negative FWS
What teeth are usually used in complete dentures and why?
Hybrid- cusp incline allows some articulation
*cusped have too much inclination
What is the RCP?
Guided occlusal relationship at most retruded position of condyles in joint cavity
Why is RCP used in edentulous patients
It is a reproducible maxillomandibular relationship
How can RCP be measured?
Get patient to close mouth and put tongue as far back as possible
Which position may be considered more comfortable for the patient when measuring occlusion?
ICP- condyles in fossa
What can be done to help you reposition blocks when measuring occlusion?
Add notches to allow yourself to reposition if required
Why is wax not used to measure occlusion?
Once recorded it is set and record blocks cannot be taken apart
Means that you cannot double check occlusion
What is used to record occlusion?
Bite recording paste
Which articulators are used in the production of complete dentures?
Average Value
What can be used to help you pick the mould for teeth in denture?
Previous dentures
Photos
Facial Profile- square, ovoid, tapered
What are the 3 numbers on the mould cards?
Top- distance between distal of canines (not mid canine line)
Mid- Height of central incisor
Low- Width of central incisor
How do you choose the width of anterior teeth?
Use old denture
Using a transparent rule (remember that marks at placed at mid canine- line and mould value is from distal)
What can be used to choose height of anterior teeth?
Previous denture
High smile line marked on blocks
Why may teeth appear shorter in denture than they look on moulds?
As some of the neck will be hidden by acrylic
What are the different types of posterior teeth?
Cuspless- HO/HU
Hybrid- FO/FU (12 degrees)
Cusped (33 degrees)
When may cusp less teeth be a good option?
If there is no good reproducible bite (teeth tend to slide around side to side)
How do you select a shade?
Shade guide
Patient preference
Previous denture
Skin colour
-> select natural shade and note down if you disagree
How should teeth be arranged?
Can be perfect alignment
Personalised- with diastema and imbrications set in
What should be written on the prescription card for next visit (try-in)?
Articulate casts to registration provided
Try-in- with shade and mould
Any special instructions- adjustments, different alignments
What is the freeway space
RVD-OVD
