Oral functions senses Flashcards
What are the 3 branches of the trigeminal nerve?
- Opthalmic
- Maxillary
- Mandibular
Which cranial nerve is the trigeminal nerve?
- CN V
What are the 12 cranial nerves?
- Olfactory
- Optic
- Oculomotor
- Trochlear
- Trigeminal
- Abducens
- Facial
- Vestibulocochlear
- Glossopharyngeal
- Vagus
- Spinal accessory
- Hypoglossal
What is the name of the nerve in the mandibular division of the trigeminal nerve?
- The inferior alveolar nerve
The mental nerve exits the mandible via the mental foramen. Where does it supply sensory branches to? (2 points)
- Chin
- Lower lip
What is another name for the inferior alveolar nerve block?
ID block (inferior dental block)
When giving an ID block does the numbness cross the midline of the face?
- No
When giving an ID block, do you want to inject into the nerve?
- No, the needle will not hit the nerve
- Want to deliver near the nerve, on the bone
- Must be able to feel the bone before injecting
If you hit the nerve while administering an ID block, what will the patient complain of?
- Will say it felt as if the needle went directly onto the lip
- Need to warn patient it will take longer to wear off - could be a few hours or days
What is paraesthesia?
- An abnormal sensation, typically tingling or pricking (pins and needles)
- It is a temporary sensation
What is Dysaesthesia?
- An abnormal unpleasant sensation felt when touched, caused by damage to the peripheral nerves
What nerves are involved in the gagging reflex? (6 points)
- Efferent (motor) response from V, IX, X, XI, XII
- The motor (secretory) visceral nerves of salivary glands are also stimulated
What is the function of the gagging reflex?
- Acts to prevent the material entering the pharynx
What is the gagging reflex evoked by?
- Mechanical stimulation of fauces, palate, posterior tongue and pharynx
What are afferent (sensory) neurons?
- These carry a message to the CNS
- The are going towards the brain or spinal cord
What are efferent (motor) neurons?
- These carry a message to a muscle, gland or other effect
- They carry the message away from the CNS
What is an interneuron?
- These neurons connect one neuron with another
- They connect the sensory neuron with the motor neuron
What are the names of the nerves involved in the gagg ing reflex? (5 points)
- V: Trigeminal
- IX: Glossopharyngeal
- X: Vagus
- XI: Accessory
- XII: Hypoglossal
Which cranial nerve is affected when someone has Bell’s P alsy?
- The facial nerve
What are the 5 branches of the facial nerve?
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
Which 2 muscles help to control food bolus and prevent spillage that are innervated by the facial nerve?
- Buccinator
- Orbicularis oris
What is the definition of Bell’s palsy?
- Any type of facial paralysis that does not have any other associated causes such as tumours, trauma and salivary gland inflammation
What are examples of things that could cause Bell’s palsy? (6 points)
- Infections (cold sores)
- Otitis medial (inflammation of the middle ear)
- Diabetes
- Trauma
- Toxins
- Temporarily by infiltration of LA to the facial nerve branches during dental treatment
When can Bell’s palsy occur due when giving an LA injection?
- Occurs when the injection is given too far distally and the parotid gland is penetrated, allowing the diffusion of LA through the loose glandular tissue, which then affect all five terminal branches of the facial nerve
What is important to do if your patient is suffering from a Bell’s palsy due to an LA injection?
- Need to protect the eye from dehydration and protect the cornea so cover the eye with a patch
When should recovery from a Bell’s palsy due to LA injection occur?
- In a relatively short time (within an hour)
What is the name for the area that an ID block should be injected?
Pterygomandibular triangle
Hitting a muscle by needle when giving an ID block may cause ‘trismus’. What is this?
Spasm of the jaw muscles, causing the mouth to remain tightly closed
Why is it advantageous to leave the root of a natural tooth when giving a patient a denture? (3 points)
- While the roots and their periodontal ligaments remain, periodontal mechanoreceptors 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
What do periodontal mechanoreceptors influence? (4 points)
- The control of jaw function
- The precision of magnitude
- Direction
- Rate of occlusal load application
Mechanoreceptors have a low threshold. What is it?
0.5mN
Do mechanoreceptors have senses of touch and pressure?
Yes
Can mechanoreceptors adapt to constant stimulus?
- Yes
- Have slowly & rapidly adapting types
What is a mechanoreceptor?
- A sensory receptor that responds to mechanical pressure or distortion
Are periodontal mechanoreceptors sensitive?
- Yes, very
- This enables us to assess the direction of forces applied to the teeth
What oral functions do periodontal mechanoreceptors contribute to? (3 points)
- Masticatory (food consistency)
- Salivation
- Interdental discrimination
What is interdental discrimination? (5 points)
- The ability to gauge the extent of mouth opening
- Coordination of masticatory movements
- Monitoring size of food particles
- Detection of ‘high’ spots
- Foil thresholds 8-60um
What are the 3 types of receptor that contribute to interdental size discrimination?
- TM joint receptors
- Muscle receptors
- PDL receptors
Is it true that the PDL is able to detect materials between teeth down to half the thickness of a human hair?
Yes
What is Shimstock and how thick is it?
- A metal foil for occlusal testing
- 8 microns thick
What is proprioception?
- Awareeness of position and orientation of body parts
What are examples of the body’s proprioceptors? (3 points)
- Joint receptors
- Muscle receptors (muscle spindles, Golgi tendon organs)
- Periodontal receptors
Is periodontal mechanoreception lost in complete dentures?
- Yes
- Conventional complete denture pro stheses 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
What can joint receptors signal? (2 points)
- Joint position (mouth open, closed)
- Joint movement (opening, closing)
What is Dysphasia?
Difficulty swallowing
What are possible causes of dysphasia? (5 points)
- Stroke
- Brain injury
- Multiple Sclerosis
- Gastroesophageal reflux disorder
- Tumours
What is an easy test to detect a stroke?
- Comparing sensorial and motor responses from both sides of the face and oropharynx
What is the main type of receptor inside the pulp?
- Nociceptors
What do nociceptors respond to and what are they usually associated with?
- Usually respond to intense (noxious) stimuli
- Usually associated with pain
Where are 3 areas where nociceptors are present, not including the dental pulp?
- Muscles
- jntois
- Mucosa
Do sensitivity receptors in the oro-facial tissues have a high or low threshold for activation?
- Low threshold for activation
- Not all regions are equally sensitive
What is 2 point discrimination?
- The ability to localize two points of pressure on the surface of the skin and to identify them as discrete sensations
- The two point discrimination threshold is the minimum separation that is consistently reported as 2 points
What does the sense of smell stimulate in the mouth?
- Stimulates salivary glands. As a result smelling disorders often affect the sense of taste
