oral functions Flashcards
masseter origin
zygomatic arch
masseter insertion
lateral surface and angle of mandible
which muscles are tender in pts with Bruxism?
masseter
temporalis
fct of masseter
elevates mandible
testing masseter
one finger IO, other on cheek
temporalis origin
floor of temporal fossa
temporalis insertion
coronoid process and anterior border of mandible
temporalis fct
elevates and retracts mandible
palpating temporalis
digital palpation between superior and inferior temporal lines, just above ear, extending forwards towards the supraorbital region
LP origin
lat surface lat pterygoid plate
LP insertion
inferior - anterior border of condyle
superior - intra-articular disc
LP fct
protrudes mandible and lateral deviation
inferior head functions with the mandibular depressors during openings
testing LP
not accessible to manual palpation - resistance test
MP origin
deep head - medial surface of LP plate
superficial head - tuberosity of maxilla
MP insertion
medial surface of angle of mandible
fct of MP
elevates and protrudes
MP testing
can’t palpate or resistive movement tests - no reliable way of examining
which muscle hit with needle during IDB can cause temp trismus?
MP
how to avoid causing trismus IDB?
contact bone to ensure correct position
movements of TMJ
rotation - initial opening - hinge
translation - wider opening - sliding
- protrusive/retrusive
what happens to the condyles in protrusive movements?
both condyles leave fossa and move forward along the articular eminences
what happens to the condyles in retrusive movements?
both condyles leave the eminences and move back into their respective fossa
Ulf Posselt
graphical recordings in occlusal and sagittal plane and profile radiography
all produced similar shape
max clenching/biting forces
varies between teeth
max between molars (200-700N)
factors affecting max bite force
psychological - fear of tooth fracture muscle mass - bigger muscles = larger forces - Bruxists often hypertrophic muscles - look for facial asymmetry muscle fibre type tooth type and position root area (PD support) nutcracker analogy
what does your predominant muscle fibre type vary depending on?
jaw morphology and diet
max bite force - tooth type and position
greatest bite force generated between 1st molars
position relative to TMJ and muscles (molars are nearer the force generating muscles and the fulcrum - TMJ)
type 1 muscle fibres
slow low forces
type 2 muscle fibres
fast stronger forces
subtypes of muscle fibres
IIA
IIX
IIB
evidence for people with ‘squarer’ jaws
have more type 2 fibres and can generate stronger bite forces
suprahyoid muscles
mylohyoid
digastric
geniohyoid
stylohyoid
infrahyoid muscles
thyrohyoid
omohyoid
sternohyoid
sternothyroid
when the hyoid bone is fixed by contraction of the infra hyoids, which muscles act as jaw depressors?
mylohyoid
geniohyoid
digastric
fct of intrinsic tongue muscles?
alter shape
intrinsic tongue muscles
longitudinal (superior and inferior)
vertical
transverse
fct of extrinsic tongue muscles?
alter shape and position
extrinsic tongue muscles
genioglossus
hyoglossus
styloglossus
palatoglossus
orbicularis oris and buccinator role
help to control food bolus and prevent spillage
dysfunction can be the 1st signs of a stroke
mandibular division of trigeminal nerve
mental auriculotemporal buccal lingual IAN n to mylohyoid
how to avoid ulceration after IDB?
warn pt not to bite lip as will be numb
paraesthesia
abnormal sensation typically tingling or pricking (pins and needles)
favourable prognosis - no complete sectioning of nerve
dysaesthesia
abnormal unpleasant sensation felt when touched, caused by damage to the peripheral nerves
function of gagging reflex
mechanical mechanism - acts to prevent material entering pharynx
what is the gagging reflex?
mechanical stimulation of fauces, palate, posterior tongue, pharynx
contract
similar to vomiting but no ejection of material
what is an oversensitive gag reflex?
a clinical problem
gag reflex neural pathway
stimulus
receptor - glossopharyngeal
sensory neuron - afferent sensorial response from CN9
association neuron
motor neuron - efferent motor response from CN5,9,10,11,12
effector - posterior part of tongue/SP contracts
response
what are also stimulated in the gag reflex?
motor (secretory) visceral nerves of the salivary glands and lacrimal gland
nerves involved in gagging reflex
trigeminal 5 glossopharyngeal 9 vagus 10 accessory 11 hypoglossal 12
afferent sensory neurons
carry a message into CNS
efferent motor neurons
carry message away from CNS
interneuron
connect one neuron with another
RPDs and gag reflex
retaining mesh in posterior part - facilitate attachment of acrylic extension
- indicated when post-dam can’t be tolerated by pt (gag reflex) - allows it to be adjusted more easily
reduces weight of large metal connector
alginates and gag reflex
take U behind pt - push up at back first so excess doesn’t run down throat
distract pt
reduce temp of water - use fast setting alginate
nose breathing
don’t want alginate behind post-dam of pt
U imp sitting up
Bell’s palsy
unilateral
motory disorder
any type of facial paralysis that does not have any other associated causes e.g. tumours, trauma, salivary gland inflammation