Sensory systems, motor systems & senses Flashcards
Your patient, who had a wisdom tooth surgically extracted under local
anaesthetic a week ago, attends complaining that her lower lip is still numb.
You examine the area and notice that the patient has been biting her lip and
there is ulceration in the area.
Can you provide an explanation for what had happened?
Patient has paraesthesia in lower lip due to ID block hitting and traumatising the nerve. This is temporary.
When will the third molar be removed?
After 2 episodes of pericoronitis.
What sensory nerves are involved in innervating the lower molars?
Mandibular branch of trigeminal nerve- inferior alveolar nerve and mental nerve
Anaesthesia, paraesthesia and dysaesthesia
Aneasthesia- loss of sensation
Paraesthesia- abnormal sensation- tingling or prickling
Dysaesthesia-abnormal unpleasant sensation felt when touched, caused by damage to periphery nerves.
What does the gag reflex do and how is it evoked?
Prevents material entering pharynx.
It is evoked by mechanical stimulation of fauces, palate, posterior tongue and pharynx.
How does the gag reflex work?
Afferent response from CN9 or efferent response from CN5,9,10,11,12 or secretory motor visceral nerves of salivary glands being stimulated resulting in a complex efferent motor and secretory response e.g. pharyngeal muscle contraction.
How to manage a patient with an over-sensitive gag reflex
Sit patient up with head tilted forward slightly, turn tray inside patient’s mouth, tell patient to breathe through nose and wiggle toes to distract them,don’t overfill tray, use fast set material or use warm water- avoid using runny material.
What could you add to an upper rpd to manage a patient with a sensitive gag reflex?
Retaining mesh
Your patient attends practice patient today but he is clearly upset and you notice he is holding a wet white hankie to his
face with his right hand. He states that “food keeps getting stuck in my cheek”. As you investigate further the patient tells
you that he has had a bad ear infection last week.
Can you describe what could have happened to explain his condition?
Bell’s palsy caused by otitis media. Facial muscles paralysed- saliva falls out of mouth and food gets stuck in cheek.
What is Bell’s Palsy?
Facial paralysis that does not have any other associated causes such as tumours, trauma and salivary gland inflammation.
What are some causes of Bell’s Palsy?
Infections, otitis media, diabetes, trauma, toxins, temporarily by infiltration of LA to the facial nerve branches during dental treatment.
What happens when the ID block is given too far distally?
Parotid gland penetrated, LA diffuses through loose glandular tissue- affects all 5 terminal branches of the facial nerve- temporary bell’s palsy
The effect of palsy due to complications of ID block and how to manage
Inability to close eyes or blink or raise the corner of mouth or puff cheeks- protect eye with a loose pad such that the cornea is protected until the protective blink reflex returns
Your next patient for the day, a retired
worker who was presented to you
seeking replacement of his ill fitting
lower partial denture. On examination,
there were only two remaining over-erupted lower canines holding his
denture in place. Although your patient
was seeking the extraction of these two
teeth and receiving a new set of
complete dentures.
What would you offer your patient as
treatment options?
While the roots and their
periodontal ligaments remain,
periodontal mechanoceptors allow
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 than is
provided by full dentures.
Psychological benefit by preventing
the feeling of total loss of natural
teeth- Makes eventual transition to
conventional complete dentures
more acceptable
Can also use precision attachments for use of the roots as retention
What is a disadvantage of implants in terms of proprioception?
Low proprioception- porcelain can chip and implant can fail.
What does the loss of periodontal mechanoreception influence?4
Control of jaw function, precision of magnitude, direction and rate of occlusal load application
What oral functions do periodontal mechanoreceptors contribute to?
Mastication (food consistency)
Salivation
Interdental discrimination
What is interdental discrimination?
Ability to gauge extent of mouth opening, monitor size of food particles and detect high spots
What is shimstock?
A metal foil used for occlusal testing.
Thickness: 8 microns
Why are complete dentures inherently unstable during normal functional jaw movements?
Loss of periodontal mechanoreception does not carry enough sensory information to restore the necessary natural feedback pathways for motor function.
Your following patient Mr
White, a retired school
teacher, arrives also
complaining that “things
get stuck in my throat”
when he eats.
What could that be?
Dysphagia- many disorders can cause/lead to food getting stuck in oesophagus e.g.- tumours, GORD, multiple sclerosis, brain injury.
Unilateral symptoms- possibly stroke
How can stroke be detected?
Comparing sensorial and motor responses from both sides of face and oesophagus.
How can you tell that the sweet
in your mouth is a polo mint with a hole without looking at it?
Two point discrimination and the aid of tastebuds and olfaction
What is two point discrimination (in the mouth)?
Compress against hard palate with tongue- mechanoreceptors will be able to identify the shape.
