FIXED PROS - Jaw Movements and Articulators Flashcards
what does conformative treatment mean?
to not change the way the teeth
- meet in ICP
- slide across each other in lateral and protrusive movements
what device is used to make sure crowns are confirmative?
an articulator
what is the purpose of an articulator?
- make sure crowns are conformative
- replicate the jaw movements and examine occlusion
- investigate proposed changes to the guidance
e.g. from group function to canine guidance
how would you know the restoration doesn’t meet the ICP?
the patient says it’ll feel too high
use articulator paper
what is the main muscle which works to open the jaw?
digastric
how much does the hinge axis usually open up to?
20mm
what is the term when the jaw opens?
translation
what’s the term when the jaw slides forward?
protrusion
describe the condylar guidance angle
the angle at which the condyle moves away from the horizontal reference plane
what does an articulator need for it to be more accurate?
a articulator eminence and the same condylar guidance angle
what is the term for the side of which the jaw moves to and away from? how does the condyle move in these instances?
the side it moves to = working side
- condyle moves to a side
the side it moves away from = non-working side
- condyle moves forward, across and down
what is immediate side shift?
a simple lateral movement of the mandible towards the working side
what is progressive side shifts
when the non-working side condyl is pulled forward and rotated toward the working side
what is canine guidance?
icp moves to a side
working side canines stay in contact
no lateral forces on posterior teeth YAY
why are lateral forces bad on posterior teeth?
increase the chance of fracturing teeth/restorations
what is group function?
when posteriors touch when going to working side
what are the 4 types of articulators?
hinge
average value
semi adjustable
fully adjustable
describe a simple hinge articulator.
can recreate ICP
can open and close
describe an average value articulator
can recreate ICP
can open, close by rotation and translation
can show lateral movements
describe a semi-adjustable articulator
can replicate:
- hinge axis position
- ICP
- RCP
- lateral movements
- use a face bow to record position of hinge axis
describe a fully adjustable articulator
can replicate:
- position of hinge axis
- ICP
- RCP
- lateral movements
can be adjusted to:
- all surfaces of glenoid fossa
- intercondylar width
- ISS
- condylar angle
what is the average distance between condyles?
110mm
what is the average distance from condyle to incisal edge?
110mm
what is the average condylar guidance angle?
30 degrees
