7 - Occlusion 3 Flashcards
What is an arcon articulator?
Condyle is set on the lower component
What is an average value articulator?
- Bennet angle is set at 15 degrees
- condylar guidance angle is set at 30 degrees
What is a semi-adjustable articulator?
Allows operator to set their own Bennet and condylar guidance angles
What are the different components of a facebow?
- bite fork
- transfer jig assembly
- earbow
- reference plane locator
What are the steps of taking a facebow registration?
- mark anterior reference point
- bite registration using bite fork
- assembly of earbow and transfer jig
- fit bow’s earpieces into patient’s ears
- align pointer with anterior reference point
- ensure bow is parallel to floor
What is the anterior reference point?
- 43mm apical to the incisal edge of 12
- approx location of infraorbital foramen
What does a facebow record?
The relationship of the maxilla to the hinge axis of rotation of the mandible
How can you mount the lower cast?
- ICP (conformative approach)
- RCP (reorganised approach)
How do you record the ICP when ICP is not obvious to technician?
- wax
- paste
How do you record the ICP when ICP is obvious to technician?
- lots of tooth contacts
- no material required
How do you record the ICP when there are free end saddles?
Record block
What are considerations when taking an occlusal record in wax or paste?
- if the material is too thick it will prop the occlusion open and this becomes a reorganised approach
- ensure cusp tips are visible through material
Define a conformative approach.
- provisions of restorations in harmony with the existing jaw relationship
- restorations do not alter the occlusion of other teeth
When is the conformative approach not utilised?
- when increased OVD is required
- teeth are out of position
- significant change in appearance
- history of occlusally related failures
What is a reorganised approach?
- new restorations are planned to a different occlusion that is defined before work begins
- should be well tolerated by patient
Why would a reorganised approach be utilised?
- ICP is non-existent or intolerable for patient
- space is required to place restorations
- RCP is a reproducible position independent of teeth
How do you guide a patient into RCP?
- bimanual manipulation
- chin point guidance
- chin point guidance with anterior jig
Describe the position of the mandible in RCP.
RCP recorded at slightly increased OVD just prior to tooth contact when the mandible is rotating about its terminal hinge axis
How do you record RCP occlusal registration?
- wax
- paste
- record block (if free end saddles)
What is the retruded arc of closure?
Initial tooth contact (RCP) can happen at any point along this arc
What is the checklist for occlusal analysis? (11)
- TMJ and MOM function
- incisor relationship
- molar relationship
- open/cross bites
- guidance
- wear facets
- restorations fractures
- occlusal contacts
- deflective contacts
- working/nonworking contacts
- mount casts
