Nerve injuries

Question 1

The following nerves affect ____ function
* Inferior alveolar nerve (V3)
* Mental nerve (V3)
* Lingual nerve (V3)
* Long buccal nerve (V3)
* Maxillary nerve and branches (V2)

Answer 1

Sensory function

Question 2

The following nerves affect ____ function
* Facial nerve (VII)

Answer 2

Motor function

Question 3

What is the most common etiology for IAN injury

Answer 3

Third molar TE

Question 4

Mandibular canal is usually located ____ and ______ to the impacted
mandibular third molars.

Answer 4

inferior and BUCCAL

Question 5

To prevent nerve injury, you should leave a __ mm safety zone above the nerve while placing the
dental implant.

Answer 5

2 mm

Question 6

If the dental implant is placed anterior to the mental foramen, then the distal surface of the implant
should be >___mm mesial to the mental foramen.

Answer 6

Greater than 2 mm anterior

Question 7

_________ injection is the most harmful to the nerve

Answer 7

Intra-fascicular

Question 8

• Branch of the mandibular nerve (V3)
• Supplies sensory innervation to the anterior 2/3rds of the
  tongue, and lingual mucosa
• Provides taste to anterior 2/3rds of tongue via chorda
  tympani (VII)
• Diameter 3.2 mm

Answer 8

Lingual nerve

Question 9

________ is most common etiology for iatrogenic trauma to the Lingual
Nerve

Answer 9

Third molar extraction

Question 10

What % of lingual nerve injuries are permanent?

Answer 10

25%

Question 11

– An abnormal sensation. Not necessarily unpleasant or painful.

Answer 11

Paresthesia

Question 12

– An unpleasant abnormal sensation.

Answer 12

Dysesthesia

Question 13

– The absence of perception of stimulation by noxious or non-noxious
stimuli.

Answer 13

Anesthesia

Question 14

Outer covering which forms a sheath around the nerve, called the ________: primary layer used for suturing/nerve repair

Answer 14

epineurium

Question 15

Nerve fibers, which are axons, organize into bundles known as fascicles with each fascicle surrounded by the ________.

Answer 15

perineurium

Question 16

Between individual nerve fibers is an inner layer of _______

Answer 16

endoneurium

Question 17

It is a Conduction block resulting from mild insult to nerve trunk.
Temporary paralysis of a nerve caused by lack of blood flow or by pressure on the affected nerve with no loss of structural continuity.

There is no axonal degeneration, and sensory recovery is complete and occurs in a matter of hours to several days.

The sensory deficit is usually mild and characterized by paresthesia

Answer 17

Neurapraxia:

Question 18

It is a more severe injury as compared to Neurapraxia. Afferent nerve fibers undergo
degeneration, but the nerve trunk is grossly intact.
-nueral tube intact, but axons are disrupted

Sensory recovery is good but incomplete.
The period of recovery is related to the rate of axonal regeneration and usually takes several months.

The sensory deficit is characterized by severe parasthesia

Answer 18

Axonotmesis:

Question 19

This is the most severe kind of nerve injury where complete disruption of the nerve takes place.
-neural tube is severed

The sensory deficit is characterized by anesthesia.

Injuries are likely permanent without repair

Answer 19

Neurotmesis:

Question 20

_______ test - This test is used to determine the response of the slowly adapting larger
myelinated fibres (A-α)
The patient’s ability to discriminate between two points is measured
This test is performed with an instrument with which the distance between the two points can be altered

Calipers can be used for this test

The test is performed with the patient’s eye closed and with 2 points of the caliper essentially touching so
that the patient is able to discriminate only one point.

The distance between the 2 points are increased in 2 mm increments until the patient is able to discriminate
between two distinct points at 6 mm- which is then considered normal

Answer 20

Level A Test

Question 21

*_______ injuries generally have a good prognosis. Generally, no treatment is required except
for periodic monitoring.

• If a nerve is compressed by an implant or adjacent bone, the implant should be reverse-torqued
  away from the nerve or removed.
• In some cases Methyl Prednisolone (Steroid) dose packs can be prescribed to the patient.

Answer 21

Neurapraxic

Question 22

What medication can be used for neurapraxic injuries?

Answer 22

Methyl Prednisone dose pack for anti-inflamm

Question 23

If tension free repair is not possible, ________ is mandatory

Answer 23

nerve grafting

Question 24

The ___________ is preferred for nerve grafting since it most appropriately matches the nerve
diameter and the fascicular number and pattern of the Trigemminal nerve

Answer 24

Sural nerve