Oral functions - senses

Question 1

What are the 3 main branches of the trigeminal nerve

Answer 1

• opthalmic branch
• maxillary branch
• mandibular branch

Question 2

What are the 12 cranial nerves

Answer 2

1 - olfactory
2 - optic
3 - oculomotor
4 - trochlear
5 - trigeminal
6 - abducens
7 - facial
8 - vestibulocochlear
9 - glossopharyngeal
10 - vagus
11 - accessory
12 - hypoglossal

Question 3

Where does the inferior alveolar nerve stem from

Answer 3

mandibular division of the trigeminal nerve

Question 4

What nerve stems off from the inferior alveolar nerve anteriorly

Answer 4

mental nerve

Question 5

where does the mental nerve exit the mandible

Answer 5

mental foramen

Question 6

what does the mental nerve supply

Answer 6

sensory branches to the chin and lower lip

Question 7

what can you do to stop sensation to the inferior alveolar nerve

Answer 7

ID block

Question 8

What are the boundaries of sensation blocking of ID block when given on e.g. left side of mandible

Answer 8

the whole to the left side of the mandible up to the left central incisor and left side of lower lip

Question 9

What should be avoided when giving ID block

Answer 9

hitting ID nerve

Question 10

what happens if you hit the ID nerve when giving ID block

Answer 10

Numbness may have remained due to temporary damage of the ID nerve

Question 11

What does paraesthesia mean

Answer 11

an abnormal sensation, typically tingling or pricking (pins and needles)

Question 12

What does dysaesthesia mean

Answer 12

an abnormal unpleasant sensation felt when touched, caused by damage to peripheral nerves.

Question 13

You plan to take an impression to prepare a new denture for you patient . As you select the tray, you recall this patient is very prone to gagging. What mechanisms are involved in the gag response?

Answer 13

Afferent (sensorial) response from IX

Efferent (motor) response from V, IX, X, XI, XII

The motor (secretory) visceral nerves of salivary glands

Question 14

What do afferent neurons do

Answer 14

Sensory neurons

- these carry a message into the CNS
i. e. going toward the brain/spinal cord

Question 15

What do efferent neurons do

Answer 15

Motor neurons

- these carry a message to a muscle gland, or other effector.
i. e. carry the message away from the CNS

Question 16

What do interneurons do

Answer 16

Connecting neuron

- these neurons connect one neuron with another
i. e. connect the sensory neurons with the motor neurons

Question 17

What cranial nerves are involved in the gagging reflex

Answer 17

Trigeminal (V)
Glossopharyngeal (IX)
Vagus (X)
Accessory (XI)
Hypoglossal (XII)

Question 18

How can you design an RPD to accomodate a strong gag reflex

Answer 18

• construct the posterior part of the RPD with a retaining mesh to facilitate the attachment of acrylic extension - means it can be adjusted more easily + reduces weight of a large metal connector
• use magnets to minimise need for large connector (however may compromise a component of RPD)

Question 19

What is bell’s palsy

Answer 19

a motor disorder
a type of facial paralysis for any type of facial paralysis that doesn’t have any other associated causes e.g. tumours, trauma and salivary gland inflammation

Question 20

How do you recognise bell’s palsy

Answer 20

• inability to wrinkle brow
• drooping eyelie; inability to close eye
• inability to puff cheeks; no muscle tone
• drooping mouth; food stuck in cheek

Question 21

What are the 5 branches of the facial nerve

Answer 21

temporal
zygomatic
buccal
mandibular
cervical

Question 22

what facial muscles help to control bolus and prevent spillage

Answer 22

orbicularis oris

buccinator

Question 23

What can cause bell’s palsy

Answer 23

• 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

Question 24

How can you cause bell’s palsy via LA

Answer 24

occurs 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 then affects all five terminal branches of the facial nerve.

Question 25

What are the effects that are seen in a patient who has got facial nerve paralysis (palsy) from ID block

Answer 25

- inability to close eye/blink | - inability to raise corner of mouth or puff cheeks

Question 26

How do you manage facial nerve paralysis from ID block

Answer 26

patients should be informed, reassured as to the transitory nature of the palsy, and the eye should be protected with a loose pad such that the cornea is protected until the protective blink reflex returns. Recovery often occurs in a relatively short time (within an hour).

Question 27

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 (photo a). Although your patient was seeking the extraction of these two teeth and receiving a new set of complete dentures, you offered him an alternative treatment option which includes decoronation of the abutments and keeping the roots to cover them with what’s known as overdentures (photos b,c). What are the physiological and psychological advantages of this treatment option?

Answer 27

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 a 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..

Question 28

why might an implanted bridge fail

Answer 28

loss of periodontal mechanoreception influences: - the control of jaw function - the precision of magnitude - direction - rate of occlusal load application

Question 29

What are the benefits of mechanoreceptors

Answer 29

- low thresholds (0.5mN) to senses of touch, pressure - adaptation to constant stimulus - slowly and rapidly adapting types

Question 30

What is a mechanoreceptor

Answer 30

a sensory receptor that responds to mechanical pressure or distortion

Question 31

How sensitive are periodontal mechanoreceptors and what to they enable us to assess

Answer 31

very sensitive | the direction of forces applied to teeth

Question 32

What oral functions do periodontal mechanoreceptors contribute towards

Answer 32

- mastication (food consistency) - salivation - interdental discrimination

Question 33

What is interdental discrimination

Answer 33

- ability to gauge extent of mouth opening - coordination of masticatory movements - monitoring size of food particles - detection of 'high' spots - foil thresholds 8-60µm

Question 34

What receptors contribute to interdental size discrimination

Answer 34

1. TMJ receptors 2. muscle receptors 3. PDL receptors

Question 35

how thick is shimstock

Answer 35

8microns

Question 36

What is proprioception

Answer 36

awareness of position and orientation of body parts

Question 37

What proprioceptors achieve proprioception

Answer 37

- joint receptors - muscle receptors (muscle spindles and golgi tendon organs) - periodontal receptors

Question 38

What do joint receptors signal

Answer 38

Proprioception: - joint position (mouth open, closed) - joint movement (opening/closing) - info usful in controlling jaw movements e.g. chewing

Question 39

how does having complete dentures impact oral function

Answer 39

- not carry enough sensory information to restore the necessary natural feedback pathways for motor function - they are inherently unstable during normal functional jaw movements

Question 40

What is dysphagia

Answer 40

swallowing difficulties

Question 41

what can cause dysphagia

Answer 41

Many disorders can cause or lead to food getting stuck in your esophagus, such as: ``` stroke brain injury multiple sclerosis gastroesophageal reflux disorder tumours ```

Question 42

Your following patient Mr White, a retired school teacher, arrives also complaining (I said it was a typical day...) that “things get stuck in my throat” when he eats. What could that be? And what should you do?

Answer 42

There could be a simple explanation for this case such as infection of the oropharynx, especially hypopharynx. However it could provide an early diagnostic of stroke which affects the swallowing reflex and this should be thoroughly investigated. Some simple procedure such as comparing sensorial and motor responses from both sides of face and oropharynx (effect of stroke is unilateral) refer to GP if unsure (could be stroke, brain injury, MS, gastroesophageal reflux disorder, tumour)

Question 43

What are nociceptors

Answer 43

Respond to intense (noxious) stimuli, that are usually associated with pain

Question 44

What nociceptors are particularly important for dentists

Answer 44

nociceptors in the dental pulp | also, muscles, joints, mucosa and PDL

Question 45

How sensitive are oro-facial tissues

Answer 45

very sensitive, receptors have low thresholds for activation

Question 46

How can you tell that the sweet in your mouth is a mint with a hole in it without looking at it?

Answer 46

You will have the taste buds and olfaction of mint. You will also have the experience of tasting polo which will facilitate the correlation However 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 that identification. Comment that if the mint is left at the surface of the tongue only, there will be no perception of shape.

Question 47

Why do smelling disorders often affect the sense of taste? " Your 11.0am patient arrives to tell you that she has a “stinking cold” and that her nose is “bunged up”. She complains that “she lost her taste”. Can you provide an explanation for her complaint?"

Answer 47

the sense of smell stimulates the salivary glands In cases of infection of nasopharynx, a loss of olfactory sense (Anosmia ) might be associated Patients have difficulty to discern between taste and olfaction, thus interchanging the terms.

Question 48

The 2:00pm patient 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?

Answer 48

The key here is the wet hankie, which indicates paralysis of the facial Students should mention Bell’s palsy since there is a sudden onset Food gets stuck due to limited action of orbicularis oris and buccinators which are important for proper mastication Otitis media may affect the facial nerve but other causal factors could also be involved

Question 49

What senses are involved in | wine tasting?

Answer 49

- Smell of the wine - Taste - Sight as it would not pass unnoticed the colour of the wine - Touch such as thickness of the liquid, presence of bubbles (it could be a sparkling wine!) and the texture of the wine. Regarding texture, there is a complex movement attain that information as you will move the liquid around. - Temperature of the wine

Question 50

Your first patient, who had a wisdom tooth surgically extracted under local anaesthetic a week ago, attends complaining that his lower lip is still numb. You examine the area and notice that the patient has been biting his lip and there is ulceration in the area. Can you provide an explanation for what had happened?

Answer 50

- Lip paresthesia - Numbness may have remained due to damage (pressure to nerve) of the mandibular division of the V CN during anesthesia or the procedure - Patient should be reminded to avoid biting lip and follow-up scheduled to evaluate paresthesia - Prognosis is favourable as long as there is no complete section of the nerve