occlusion Flashcards
when do we carry out basic occlusal exams
part of every history and exam
when do we carry out comprehensive occlusal exams
TMJ disorders, crowns , bridges
what type of occlusal exams do we have
basic
or comprehensive
what type of skeletal patterns can we have
class 1 class 2 class 3
what are class 1 patterns like
lower jaw in proportion to upper jaw
what are class 2 patterns like
lower jaw is retruded
what are class 3 patterns like
lower jaw is protruded
how do we look for asymmetry
Tell the patient what you are doing and look at the patient straight on
Look for any obvious deviations
what do we look for in the TMJ
stand behind pt and listen for clicks crepitus and disc movement
how do we check for the range of movement of the TMJ
Willis height gauge & measure in mm
what else do we check in terms of the TMJ
size
symmetry
tenderness
tonicity
what is the origin of the master
zygomatic arch
what is the insertion of the master
lateral wall of the ramps and anglee of the mandible
what is the innervation of the masseter
mandibular division of the V3
what is the action of the masseter
clenching
what is the origin of the temporalis
temporal surface of the skull and temporal fascia
what is the insertion of the temporalis
coronoid process and anterior border of the ramps
what is the innervation of the temporalis
V3 of the CNV
what is the action of the temporalis
action
what is the origin of the lateral pterygoid
lateral surface of lateral pterygoid plate and greater wing of sphenoid
what is the action of the lateral pterygoid
protrusion and opening
what do we look for in the IO
Sharp cusps on the upper arch will cause lines that match with occlusion
Cheek ridging occurs when the patient bites down on buccal mucosa
Tongue scalloping occurs by tongue being squashed against teeth
DEFINE ICP
The position of maxilla and mandible when teeth are in maximal intercuspation
Most people have a stable ICP, an unstable ICP occurs when patient bites diff every time
What is an overjet
horizontal distance between cusp tips when teeth are in ICP
what is an overbite
Vertical distance between cusp tips when teeth are in ICP
what is a crossbite
One (or multiple teeth) are out of normal ICP relationship
what is RCP
The position of the mandible in the 1st point of contact upon closing when condyle is placed most superiorly and posteriorly in glenoid fossae
when do we need to record the RCP this on a patient
on patients who do not have a stable ICP
which mandible is consistently reproducibility
the RCP
how to record the contacts
articulating paper
what are the types of articulating paper
thick 250 microns
thin 40 microns
ideal 8 microns
what is the average perception
10 microns
when is thick articulating paper used
prosthetic work
what is the thin articulating paper used for
simple cons work
what is the ideal articulating paper used for
complex crown work
describe cracked cusp syndrome
Pain on releasing on biting and very well localised
Why? Interferences/ weakened cusps/ Bruxism/ Trauma/ Extreme temp change in tooth
stages of cracked cusp syndrome
Occlusal loading of a cusp associated with a crack opens the crack (microcracks)
Crack fills with fluid
Release of occlusal loading causing crack to rapidly close
Some fluid is expelled to surface of tooth
Some fluid is forced into D tubules leading to pulp stimulation & pain on release
tx options for cracked tooth syndrome
Desensitise area with fluoride varnish/ tubule occlusion with bonding agents
Remove cracked portion of the tooth and place direct restoration
Place indirect restoration (crown/onlay)
what is the origin of the anterior belly of the digastric muscle
digastric fossa of the mandible
what is the insertion of the anterior belly of the digastric muscle
intermediate tendon
what is the innervation of the posterior belly of the digastric muscle
facial nerve
what do the digastric muscles do
depresses and draws the mandible back as it opens
The digastric muscle elevates the hyoid bone (used in swallowing & speech)
what is the function of the articulator
The job of articulators are to mimic a patients jaw movements
Essentially we are trying to replicate jaw movements of plaster models
To allow examination of the occlusion (ICP, RCP, Protrusive and lateral movements)
To allow fabrication of restorations (Crowns, bridges, dentures, splints)
To investigate proposed changes to the occlusion (change from CG to GF)
what are the types of articular
Simple hinge
Average value
Semi adjustable
Fully adjustable
describe simple hinge articulator
Open and closes the mouth by rotation only
Useful in seeing if what is being made will be high in ICP
describe average value articulators
Average value allows for lateral excursion and protrusion as they have moveable joints
Values can’t be altered from patient to patient
Set up for average distances for average patients
describe semi adjustable articulators
Can replicate ICP, RCP, Lateral movements and position of hinge axis (relationship of condyle
Must be used with face bows
describe fully adjustable
Can replicate Position of hinge axis (which can’t be measure on a patient) (& all of above)
what is the working side in the upper
buccal
what is the working side on the lower
lingual
what do we do if the tooth is high in ICP and lateral excursion
reduce cusp height
what do we do if the tooth is high only in ICP
make deeper fossa
what are the muscles of mastication
The masseter
Temporalis
Lateral pterygoid
Medial pterygoid
