12. Occlusal Concepts Flashcards
1
Q
Define ‘occlusion’
A
how teeth meet together or don’t (linked to contact with hard and soft tissue)
2
Q
Why is occlusion an important concept?
A
- huge variation between patients
- need teeth to work harmoniously in each patient after treatment
3
Q
What determines occlusion?
A
- TMJ
- CNS
- masticatory muscles
4
Q
The TMJ is a .. .. .. which has rotation around a … … allowing …
It is … within the body
A
- freely movable joint
- transverse axis
- gliding movements
- unique
5
Q
How does the TMJ move?
A
- condyle rides against the glenoid fossa in temporal bone
- disc is attached to lateral and medial poles like a cap
6
Q
Cavities in the TMJ
A
- 2 joint cavities
- 1 superior between temporal bone and disc
- 2 inferior between disc and head of condyle
- not linked
7
Q
TMJ allows what?
A
rotation of the mandible
8
Q
3 planes of the TMJ
A
- intercondylar axis
- vertical axis
- saggital axis
9
Q
2 translations of the TMJ
A
- anterio-posteriorly
- laterally
10
Q
What is ICP?
A
- intercuspal position
- or MI - maximum intercuspation or centric occlusion (US)
- occlusal vertical dimension (OVD)
11
Q
What is CR?
A
- centric relation
- position of mandible on its retruded arc of closure
12
Q
What is RCP?
A
- retruded contact position
- position of mandible when first tooth contact occurs on retruded arc of closure
13
Q
What is resting vertical dimension position?
A
- or resting vertical postural position
- the least reproducible position
14
Q
Explain rotating/orbiting functions of occlusion
A
- in excursion the WS condyle rotates mainly
- the NWS condyle tends to orbit with much more open/sweeping path
- this leads to distinct asymmetry
- important as how the opposing cusp sweeps across the occlusal surface, you can build ridges and grooves to provide harmonious occlusion
15
Q
Chewing starts and ends at what?
A
ICP/MI
16
Q
From ICP, what is Posselt’s border movements?
A
- protrusion (maximum)
- separation (maximum) while maintaining protrusion
- closing mouth along RAC until tooth contact established
- sliding back into ICP
17
Q
Attachments of masseter
Role
A
- from zygomatic arch
- to lower lateral aspect of ramus - for closing
18
Q
Attachments and role of temporalis
A
- temporal fossa to coronoid process
- closing
19
Q
Attachements and role of medial pterygoid
A
- superficial and deep heads attached to medial surface of angle of mandible
- for closing
20
Q
Attachments and role of lateral pterygoid
A
- superior and inferior heads on pterygoid fovea, neck on condyle and TMJ capsule
- for opening protrusion and side to side
