Oral Functions: Sensory and Motor Systems

Question 1

What might an ulceration after wisdom tooth extraction mean?

Answer 1

temporary damge of the ID nerve due to irritation can cause prolonged numbness of the lip causing patient to ulcerate the area

Question 2

What sensory nerves are involved in innervating the lower molars?

Answer 2

trigeminal nerve
mandibular
the inferior alveolar nerve

Question 3

What does the inferior alveolar nerve anteriorly give off and what does that supply?

Answer 3

the nerve gives off the mental nerve which exits the mandible via the mental foramen (supplying sensory branches to the chin and lower lip).

Question 4

What is paraesthesia and dysaesthesia?

Answer 4

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

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

Question 5

What is gagging and how is it evoked?

Answer 5

• Acts to prevent material entering pharynx
• Evoked by mechanical stimulation of fauces, palate, posterior tongue, pharynx
• Similar to vomiting, but there is no ejection of material
• Some patients gag when instruments and/or materials are placed in the mouth

Question 6

What is a clinical gag problem?

Answer 6

oversensitivity

Question 7

What nerves are involved in the gagging relex?

Answer 7

Afferent response from 9th cranial nerve

Efferent (motor) response from 5, 9, 10, 11, 12

The motor (secretory) visceral nerves of salivary glands
are also stimulated

Question 8

How is the gagging reflex managed in RPD?

Answer 8

The posterior part of this RPD is constructed with a retaining mesh to facilitate the attachment of 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.

Question 9

What should you instruct the patient before placing the tray in?

Answer 9

breathe through nose

Question 10

A patient keeps getting food stuck in their cheek, what might this be a sign of?

Answer 10

bells palsy

Question 11

How can Bell’s Palsy be caused in a dental setting?

Answer 11

Temporarily by infiltration of LA
to the facial nerve branches during dental treatment

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.

Occurs during an ID block

(This occurs as the operator has NOT identified bone before injecting)

Question 12

What is bells palsy?

Answer 12

any type of facial paralysis that does not have any other associated causes such as tumors, trauma and salivary gland inflammation.

Question 13

What two facial muscles are innervated by the facial nerve and help to control food bolus and prevent spillage?

Answer 13

orbicularis oris
buccinator

Question 14

What are the facial nerve branches?

Answer 14

temporal
zygomatic
buccal
mandibular
cervical

Question 15

What are the non dental causes of bells palsy?

Answer 15

• Infections (HSV/ Cold sores)
• Otitis Media (inflammation of the middle ear)
• Diabetes
• Trauma
• Toxins

Question 16

How is the facial nerve paralysis managed?

Answer 16

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.

usually recovers within an hour

Question 17

When giving ID block what should be contacted and why?

Answer 17

Bone should be contacted to ensure correct position within the pterygomandibular triangle and not t hit soft tissues.

Question 18

What muscle should the ID block avoid and why?

Answer 18

medial petrygoid
Hitting this muscle by the needle accidentally might cause “trismus”

Question 19

What is the benefit of overdentures over complete dentures?

Answer 19

Overdentures will have retained roots, which maintains the presence of mechanoreceptors and proprioceptors due to PDL

Question 20

What are the signs of Bell’s Palsy in patients?

Answer 20

Inability to close the eye or blink

Inability to raise the corner of the mouth or puff the cheeks

Question 20

What does the loss of periodontal mechanoreception influence?

Answer 20

• the control of jaw function
• the precision of magnitude
• direction
• rate of occlusal load application

Question 21

What mechanism is involved in initiating the gag response and where?

Answer 21

Mechanoreceptor stimulation of the:

Soft Palate
Posterior Tongue
Pharynx

Question 22

What can mechanoreceptors do?

Answer 22

adapt to constant stimulus

Question 23

What functions do periodontal mechanoreceptors contribute to?

Answer 23

enabling us to assess the direction of forces applied to teeth
* They contribute to various oral functions:
– Mastication (food consistency)
– Salivation
– Interdental discrimination

Question 24

What is the interdental discrimination the PDL mechanoreceptors can carry out?

Answer 24

• Ability to gauge extent of mouth opening
• Coordination of masticatory movements
• Monitoring size of food particles
• Detection of ‘high’ spots

Question 25

What thickness is the periodontal ligament able to detect?

Answer 25

half the thickness of a human hair?

Question 26

What is the thickness of shimstock foil and what is it used to identify?

Answer 26

8 microns
for infraocclusion (restorations that are too low)

Question 27

What is lost in complete dentures?

Answer 27

loss of periodontal mechanoreception

Conventional complete denture prostheses do not carry enough sensory information to restore the necessary natural feedback pathways for motor function.

Regardless of the technical excellence of such prostheses, they are inherently unstable during normal functional jaw movements.

Question 28

What are the possible causes of dysphagia?

Answer 28

• stroke
• brain injury
• multiple sclerosis
• gastroesophageal reflux disorder
• tumours

Question 29

How can strokes be detected?

Answer 29

Strokes have uni-lateral symptoms, therefore if we compare the sensorial and motor responses from both sides of the face and orophharynx
then we can detect if a patient has suffered a stroke.

Question 30

If a patient complains that they are getting food stuck in their throat while eating, what condition is this called?

Answer 30

dysphagia

Question 31

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

Answer 31

You will have the taste buds and olfaction of mint.

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.

Question 32

What does the sense of smell stimulate?

Answer 32

salivary glands
smelling disorders often affect the sense of taste

Question 33

What might happen in cases of nasopharynx infection?

Answer 33

loss of olfactory sense

Question 34

What is loss of olfactory sense called?

Answer 34

anosmia

Question 35

What do nociceptors respond to?

Answer 35

intense noxious stimuli that are usually associated with pain

Question 36

Which branch of the maxillary nerve innervates the anterior part of the hard palate immediately behind the central and lateral incisors?

Answer 36

Nasopalatine nerve