Occlusion Flashcards
What is occlusion?
The study of how the teeth meet together
What is the aim of working with occlusion?
Getting the teeth to work harmoniously
What are the 4 determinants of occlusion?
Occlusion
TMJ
Masticatory muscles
CNS
How does the CNS control occlusion?
The brain controls stress, anxiety, habitual habits, conditions like PTSD all of which will affect occlusion
Describe the movement of the TMJ?
Freely movable
Where does the disc of the TMJ sit?
Between the temporal bone and the condyle
What is the function of the disc of the TMJ?
Acts as lubricant which allows the bones to move past each other, so the borns don’t wear out
Name the 2 joint cavities of the TMJ
Superior (between the temporal bone and disc) and Inferior (between the disc and head of condyle)
What are the 3 planes of rotation around the mandible by the TMJ?
Intercondylar axis
Vertical axis
Sagittal axis
What is intercuspal position?
How the teeth meet within maximum position
What is centric relation?
Position of mandible on its retruded arc of closure (position of the jaw when you bite and your teeth come together)
What is the retruded contact position?
Position of the mandible when first tooth contact occurs on retruded arc of closure = premature contact between teeth
What is the least reproducible position fo the mandible?
Rest/postural position
What is the working side of the teeth?
The side the teeth are moving towards, the teeth are touching
What is the non-working side of the teeth during rotation?
The side the teeth are moving away from, the teeth are not touching
Movement towards the WS condyle will cause what type of movement?
Rotation
Movement towards the WS condyle will cause what type of movement on the NWS condyle?
Orbits on a sweeping path
Other than rotation what movement can the TMJ make?
Translation
What determines the borders of Posselt’s border movements?
Superiorly by teeth contact
All others by TMJ and ligaments
How does the first 20mm of jaw opening occur?
How does the next 25mm occur?
Rotation of TMJ
Translation of TMJ
When you close the jaw what position does it go into?
Maximal protrusion
Attachments of masseter?
Function of masseter?
Zygomatic arch to lower lateral aspect of ramus.
Closing the jaw
Attachments of temporalis?
Function?
Temporal fossa and coronoid process.
Closing
Attachments of medial pterygoid?
Function?
Superficial and deep heads attach to medial surface of angle of mandible
Closing
Function of superior and inferior heads of lateral pterygoid?
Superior = opening and closing Inferior = opening and side to side movement
