oral functions 2 Flashcards
what are the 3 branches of the trigeminal nerve
- ophthalmic branch
- maxillary branch
- mandibular branch
what are the sensory branches of the trigeminal nerve
- ophthalmic branch
- maxillary branch
what are the mixed branches of the trigeminal nerve
mandibular branch
what cranial nerve is the trigeminal nerve
cranial nerve 5 / V
name the cranial nerves
I. Olfactory II. Optic III. Oculomotor IV. Trochlear V. Trigeminal VI. Abducens VII. Facial VIII. Vestibulochlear IX. Glossopharyngeal X. Vagus XI. Accessory XII. Hypoglossal
what does the mandibular branch of the trigeminal nerve innervate
> inferior alveolar (dental) never
= the largest terminal branch of
where does the inferior alveolar (dental) nerve travel
travels in the mandibular canal as far as the mental foramen
where is LA injected for the lower posterior teeth
inferior alveolar (dental) nerve
what is the mental nerve
the sensory branch of the inferior alveolar nerve
the inferior nerve gives off the mental nerve anteriorly which exits the mandible via the mental foramen
what does the mental nerve supply
the chin and lower lip
what is injection to numb the lower posterior teeth called
the inferior alveolar nerve block
or
ID block
name the branches of the mandibular nerve
- inferior alveolar nerve
- lingual nerve
- buccal nerve
- nerve to mylohyoid
- mental nerve
when performing the ID block what part of the face is numbed
the side of the face where the injection was given up to the midline (central lower incisor)
when giving LA - where do you want the injection to hit and where dont you want the injection to hit
you want the needle to hit bone - want to deposit the LA next to the nerve
you dont want the needle to hit the actual nerve or soft tissues
what does directly hitting the nerve with the needle cause
temporary damage of the ID nerve
(patient will feel as though you have directly hit their lip)
this will take longer for the numbness to wear off
make sure to warn patient not to bite their lip as they wont be able to feel pain if they do bite it
nerve has been traumatised but there was no complete intersection of the nerve so there is not permanent damage
define anaesthesia
loss of sensation
define paraesthesia
an abnormal sensation (typicall tingling or prickling / pins and needles)
caused cheifly by pressure on or damage to the peripheral nerves
define dysaethesia
an abnormal unpleasant sensation felt when touched
caused by damage to peripheral nerves
where should the needle be in the correct position within to ensure they hit the bone
correct position within the pterygomandibular triangle
what happens when the needle accidentally hits the muscle instead of the bone
might cause trismus
also called lock jaw
this is reduced opening of the jaws (limited jaw range of motion)
can be temporary or permanent
what is the purpose of the gag reflex
prevent material entering the pharynx
what evokes the gag reflex
mechanical stimulation of fauces, palate, posterior tongue and pharynx
when does the gag reflex cause a clinical problem
when it is oversensitive
what nerves are involved in the gag reflex
efferent (motor) response from
- V = trigeminal
- IX = glosspharyngeal
- X = vagus
- XI = accessory
- XII = hypoglossal
the motor (secretory) visceral nerves of the salivary glands are also stimulated
name 3 types of neurons based on function
> afferent / sensory neurons
efferent / motor neurons
interneuron / connecting neuron
what are afferent / sensory neurons
these carry a message into the CNS
They are going towards the brain or spinal cord
what are efferent / motor neurons
these carry a message to a muscle, gland or other effector
they are carrying messages away from the CNS
what are interneurons
these neurons connect one neuron with another
in many reflexes interneurons connect the sensory and motor neurons
what should be done when making a RPD for a patient with a problematic gag reflex
the posterior part of this RPD is constructed with a retaining mesh to facilitate the attachment of the acrylic extension
this design is indicated when the post dam cannot be tolerated by the patient (gagging reflex) allowing it to be adjusted more easily
in addition this approach will reduce the weight of a large metal connector
what is bell’s palsy
a motor disorder
cranial nerve VII (facial nerve) affected
what are the features of bell’s palsy
- inability to wrinkle brow
- drooping eyelid
- inability to close eye
- inability to puff cheeks
- no muscle tone
- drooping mouth
- food stuck in cheek
what are the branches of the facial nerve
- temporal
- zygomatic
- buccal
- mandibular
- cervical
what are the functions of the orbicularis oris and the buccinator
help to control food and prevent spillage
do all patients with facial paralysis have bell’s palsy?
no bell's palsy is coined for any type of facial paralysis that does not have any other associate causes such as - tumours - trauma - salivary gland inflammation
what are causes of bell’s palsy
- infections > HSV > cold sores - otitis media > inflammation of the middle ear - diabetes -trauma - toxins - temporarily by infiltration of LA to the facial nerve branches during dental treatment
how can LA affect the facial nerve
when the injection is given too far distally and the parotid gland is penetrated allowing the diffusion of the LA through loose glandular tissue which ten affects all 5 terminal branches of the facial nerve
how should facial nerve paralysis caused by LA be managed
- inform patient
- reassure them about the transitory nature of the palsy
- protect the eye with a loose pad so that the cornea is protected until the protective blink reflex returns
(stops eye dehydrating) - recovery often occurs in a short period of time
what is the advantage of decoronating the crown of the tooth but leaving the roots
keep the PDL which gives proprioception so you know how much force is on the area
what do peridontal mechanorecpetors allow for
finer discrimination of food texture, tooth contacts and levels of functional loading
a better appreciation of food and a more precise control of mandibular movements is given than is provided by full dentures
what does the loss of periodontal mechanoreception influence
- control of jaw function
- precision of magnitude
- direction
- rate of occlusal load application
what are the thresholds of mechanoreceptors
low thresholds
(0.5mN)
senses of touch, pressure
what is a mechanoreceptor
a sensory receptor that responds to mechanical pressure or distortion
what oral functions do periodontal mechanorecpetors contribute to
- mastication (food consistency)
- salivation
- interdental discrimination
what is involved in interdental discrimination
- ability to gauge extent of mouth opening
- coordination of masticatory movements
- monitoring size of food particles
- detection of high spots (very sensitive to any change on the occlusal surface)
- foil thresholds 8-60 micrometres
what receptors contribute to interdental size discrimination
- TMJ receptors
- muscle receptors
- PDL receptors
what is shimstock
a metal foil for occlusal testing
thickness = 8 microns
what is proprioception
self sense
awareness of position and orientation of body parts
what is proprioception served by
joint receptors muscle receptors > muscle spindles > golgi tendon organs periodontal receptors
what do joint receptors signal
> joint position
- mouth open, closed
> joint movement
- opening, closing
what is dysphagia
swallowing difficulties
what causes dysphagia
many disorders can cause or lead to food getting stuck in your oesophagus such as
- stroke
- brain injury
- multiple sclerosis
- gastroesophageal reflux disorder
- tumours
what can be the first sign of a stroke
dysphagia
how do you detect a stroke
compare sensorial and motor responses from both sides of face and oropharynx
stroke usually unilateral
one side of face is fine the other is not
what are nociceptors
respond to intense (noxious) stimuli, that are usually associated with pain
what are the most important nociceptors for dentists
the ones inside the dental pulp
where are nociceptors found in the mouth
- dental pulp
- muscles
- joints
- mucosa
- PDL
what is sensitivity like around the face and the mouth
oro-facial tissues are very sensitive
receptors have low thresholds for activation
but not all regions are equally sensitive
how can you tell that the sweet in your mouth is a polo without looking at it
- You will have the taste buds and olfaction
- You will also have the experience of tasting polo which facilitate the correlation
- You acquire the format of the mint by compressing it against the hard palate with the tongue
- Mechanoreceptors will be able to identify the format since the 2 point discrimination of both tissues allows than identification
what stimulates salivary glands
sense of smell
can can affect sense of taste
smelling disorders
infections of nasopharynx
loss of olfactory sense (anosmia)
