Occlusion for conventional dentures Flashcards
What are the different types of record block?
- wax only
- shellac base with wax
- heat cured base
What are the properties of a wax only record block?
- less retentive
- cheap
- lots of space for setting teeth
What are the properties of a shellac base record block?
- more stable
- more expensive
- limited space for setting teeth
What are the properties of a heat cured base?
- very stable
- expensive
- least space for setting teeth
What equipment is required for a jaw registration?
- heat source
- hot plate
- wax knife
- foxes bite plate
- dividers or willis bite gauge
- bite registration paste
What are the steps of jaw registration?
1 - adjust upper for retention
2 - adjust upper for tooth position
3 - adjust upper for occlusal plane
4 - lower tooth position and jaw relationship
5 - measure vertical dimension and establish face height
6 - record registration
7 - select shade, mould and setting
How should you adjust a record block for retention?
- not too much lip support (or else will drop)
- trim rim labially and buccally
- ensure no overextension
How should you adjust the upper record block for tooth position?
- lip support
- incisal level
- midline
- buccal corridor
- occlusal plane
What is the recommended nasiolabial angle for lip support?
90 degrees (actually usually 96 degrees)
What should be marked on to the record block for tooth position and incisal level?
- smile / lip line
- canine line
What should be used as reference for the midline?
- incisive papilla
- filtrim of the lip
- nose to some extent
What is the buccal corridor?
- space between cheeks and teeth when smiling
- in a small percentage of people
What reference points are used to adjust the occlusal plane?
Anterior = interpupillary
Posterior = ala tragus line
What is the neutral zone?
The area in which the forces of the lips and cheeks, and the tongue are balanced, denture should be placed here.
What happens if a denture is not designed within the neutral zone?
Too buccally - cheek movement dislodges denture
Too lingually - tongue movement dislodges denture
Lingual flange incorrect shape - tongue lifts denture
Define class I skeletal relationship.
Shallow overjet and overbite
Define class II div 1 skeletal relationship.
Increased overjet and shallow overbite
Define class II div 2 skeletal relationship.
Increased overjet and deeper overbite
Define class III skeletal relationship.
Edge to edge incisors or reverse overjet ± posterior cross bite
What happens when there is excessive freeway space?
- reduced masticatory function
- overclosed facial appearance
- cheek biting
- TMJ symptoms
What happens when there is reduced or inadequate freeway space?
- excessive load on denture bearing area
- continuous muscular activity results in pain
- aesthetic complaints (“teeth are too big”)
- noisy dentures
What is the ideal FWS?
- 2-4mm
- don’t change more than 1-2mm from patients initial FWS even if it is not in the recommend range
How do you prepare a record block to record registration?
- cut notches
- apply adhesive if using paste
