CSAR 21-24 - Occlusion Flashcards
What parts of the body are involved in occlusion?
Teeth Periodontium MOM TMJ Neurological system
What programmes dynamic occlusion and how?
Central Pattern Generator (CPG)
Adapts into teeth as much as possible, negotiating interferences and hard to change pathway once CPG imbedded
What are the 2 varied movements in functional occluding pathways?
Broad (cow like) –> broad wide movement
Constrained (rat like) –> up and down
How may functional occlusion by adapted and not adapted to?
Adapted if functional pathway restored
Can adapt through tooth wear or loosening of teeth
No adaption when incorrect guidance or palatal surfaces are too convex
Define fremitus.
When bite together and tooth moves out of the way
What methods can be used to increase inter-occlusal space?
Prep - occlusal reduction
Relative axial tooth movement - Dahl concept - used for cracked tooth syndrome
(Ortho)
What static occlusion goals want to be achieved?
Simultaneous bilateral stable posterior contacts apically directed, protecting anterior teeth from splaying
Want cusp fossa relationship
What dynamic occlusion goals want to be achieved?
Smooth gliding excursive movement - canine/group function
Want immediate separation of anterior teeth
What are the movements of the condyle in lateral excursion?
WS –> rotation
NWS –> orbit
What are the condylar movements in jaw opening?
20mm of opening - hinge opening
Condyle then translates down articular eminence to open further
Why is a 1.Arcon and 2.Non-arcon articulator and their use?
- Articulated condyle (e.g.Whipmix) - common in fixed pros to replicate hinge movement of mandible and for changes in OVD
- Non-articulated condyle (e.g.Dentatus) - used for removable pros
Why is a face bow used for a semi-adjustable articulator?
Facebow allows maxillary casts to be in relation to the condyles in dynamic occlusion
Why is dynamic occlusion inaccurate from a simple hinge articulator?
Simple hinge rotation axis not anatomical - it is lower down
What face bow is used for a fully adjustable articulator (unnecessary accuracy)?
Kinematic record - true hinge axis
What face bows are used for a semi adjustable articulator (sufficient accuracy)?
Earbow record - arbitrary hinge axis
Kois Dento-Facial Analyser - arbitrary hinge axis with average values
What does the Kois face bow measure?
Facial midline and aesthetic plane
What is the difference between 1.conformational and 2.reorganisational approaches with occlusion?
- Fitting in with existing occlusion and ICP
- Where original ICP can not be used due to lack of inter-occlusal space: worn dentition, missing teeth (no replacement = dento-alveolar compensation) and complete overbite patient
What reference point is used when reorganising the occlusion?
New reference point Centric relation (seated condyle) is always a reproducible position as it is joint position and nothing to do with teeth
What is RCP?
Tooth to tooth position
First contact of teeth when condyles are in centric relation (on the retruded arc of closure)
How does a pt go from RCP into ICP?
90% of people slide from RCP to get their teeth to maximally interdigitate into ICP
When is the RCP-ICP slide changed?
To gain anterior space by changing OVD
Preparing tooth involved in slide, most commonly last tooth in arch (7)
If a large horizontal slide, not planned, what can happen due to the changed RCP?
Muscles deprogramme/relax
Neuromuscular functional pathway lost
Condyles seat into centric relation
Mandible drops back and can lead to increased OJ/ anterior open bite
What are the manipulation techniques of finding centric relation?
Bimanual
Chin point
Schuyler technique - tongue to roof of mouth - reproducible
What are the anterior midpoint stop appliances of finding centric relation?
Lead gauge - block for anterior teeth to bite on, therefore back teeth out of occlusion, allows slide
Kois deprogrammer
Gothic arch tracing - when missing lots of teeth
