Jaw Movements and Articulators Flashcards
What are crown made on and why?
Made on an articulator as it can replicate jaw movement
Name the different moments/ positions your jaw can be in
- Intercuspal position (ICP)
- Protrusion
- Lateral movement
What is rotation
The jaw rotating up to 20mm
What is translation of the jaw
The jaw coming forward from the gelnoid fossa
Where does the jaw translate from and where to?
Slides from the glenoid fossa to the articular eminence
How do you open you jaw?
You rotate it and translate it at the same time
What is condylar guidance
Sliding of the articular eminence when the jaw comes forward
When moving your jaw side to side what do we call the slide you are slide towards
The working side
Which forces are posterior teeth designed for?
Vertical forces
What happens if posterior teeth experience excess horizontal forces?
They can crack
They can were down
Name the 2 groups patient can fit into when we describe their occlusion
- Canine guidance
2. Group function
What is canine guidance
When the patent moves their jaw to the side only the canines stay in contact
When placing an amalgam or composite restoration what type of treatment are we aiming to do?
Con formative treatment
What is con formative treatment
Any restoration that does not change the way the teeth:
- Meet together in ICP
- Slide across each other in lateral and protrusive movements
What does ICP stand for
Intercuspal position
What are crowns made on?
Articulators
What do articulators do?
They aim to replicate the jaw arrangements and movements of plaster models
How do we change from the ICP to an open position
- Rotation
2. Translation
How much does the jaw rotate when it opens
20mm
Around which point does the jaw rotate
The terminal hinge axis
Where is the terminal hinge axis?
The central point of the condyle
Name the main muscle involved in opening the jaw
Digastric muscle
What does the digastric muscle do?
It pulls the mandible backwards
What is translation
The forward movement of the jaw
Where does the jaw slide down when it is opening/ translating
The articular eminence
Which muscle pulls the jaw forwards and down?
Lateral ptergoid