Occlusion 1 Flashcards
TMJ anatomy
Starting from right:
Articular eminence
Superior head of lateral pterygoid
Inferior head of lateral pterygoid
Condylar head
Retrodiscal tissue
Inferior synovial cavity
Articulator disc
Superior synovial cavity
Mandibular fossa
What do muscles of mastication do?
Depression, elevation and lateral movements of mandible
What do suprahyoid muscles do
Elevate hyoid bone or depress mandible
Examples of MoM
Temporalis
Lateral pterygoid
Medial pterygoid
Masseter
What does temporalis do?
Elevates and retracts mandible
Assists in rotation
What does masseter do?
Elevates and protracts mandible
Assists in lateral movement
2 major types of mandibular movement?
Rotation and translation
What is rotation movement
Small amount of mouth opening (up to 20mm)
Condyle and disc remain within fossa
No downwards or forwards movement
Also known as hinge movement
What is the terminal hinge axis?
Rotation of condylar heads around an imaginary horizontal line through the rotational centres of the condyles
Imaginary line is termed terminal hinge axis
What is translation of the condyle?
Lateral pterygoid contracts
Condyle and disc begin to move
Travel downwards and forwards (may also travel laterally) along incline of articular eminence
What is a facebow
Records relationship of maxilla to terminal hinge axis of rotation of mandible and distance between condyles for semi adjustable articulators
What does posselts envelope show?
Extremes of mandibular movement
Border movements of mandible in sagittal plane
What are the movements in posselts envelope
P= Protrusion
E= Edge to edge
ICP= Intercuspal position
RCP= Retruded contact position
R= Retruded axis position
T= Maximum opening
What is intercuspal position
Tooth position regardless of condylar position
Maximum interdigitation of teeth
Types of occlusion
Dynamic
Static
How to mark tooth contacts
Articulating paper
Millers forceps
What are the functional cusps in static occlusion
Lingual cusps of upper posterior and buccal cusps of lower posterior
Types of dynamic occlusion
Canine guidance
Group function
Protrusion
What is canine guidance
When mandible moves to working side contact made only between canines with no posterior tooth contacts- mutually protected occlusion
What is group function
When mandible moves to working side, multiple teeth in contact on working side- toothwear
Problem with dynamic occlsuion
Occlusal interference (working side, non working side, protrusive)
What is lateral translation of the mandible also known as?
Bennet movement
What is this angle
Bennet angle
Types of articulators
Average value
Semi-adjustable
Arcon
How to register ICP
Wax- ICP not obvious- very thin- cusp tip visible
Registration paste- ICP not obvious- silicone paste- thin
Record blocks- free end saddles- casts cannot be hand articulated
No materials- ICP obvious- multiple teeth contact when bite together
What is conformative approach/reorganised approach?
Conformative- ICP registration without OVD increase
Reorg- opposite- want change
When not to use conformative approach
Need to make space for restorations
Want change in aesthetics
Teeth out of position
Techniques to put teetb intk RCP?
Bimanual manipulation
Chin point guidance
Chin point guidance with anterior jig
What is the retruded contact position
First tooth contact when mandible is in retruded axis position
How to register RCP
Wate
Paste
Record block
