Nerve injuries Flashcards
The following nerves affect ____ function
* Inferior alveolar nerve (V3)
* Mental nerve (V3)
* Lingual nerve (V3)
* Long buccal nerve (V3)
* Maxillary nerve and branches (V2)
Sensory function
The following nerves affect ____ function
* Facial nerve (VII)
Motor function
What is the most common etiology for IAN injury
Third molar TE
Mandibular canal is usually located ____ and ______ to the impacted
mandibular third molars.
inferior and BUCCAL
To prevent nerve injury, you should leave a __ mm safety zone above the nerve while placing the
dental implant.
2 mm
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.
Greater than 2 mm anterior
_________ injection is the most harmful to the nerve
Intra-fascicular
- 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
Lingual nerve
________ is most common etiology for iatrogenic trauma to the Lingual
Nerve
Third molar extraction
What % of lingual nerve injuries are permanent?
25%
– An abnormal sensation. Not necessarily unpleasant or painful.
Paresthesia
– An unpleasant abnormal sensation.
Dysesthesia
– The absence of perception of stimulation by noxious or non-noxious
stimuli.
Anesthesia
Outer covering which forms a sheath around the nerve, called the ________: primary layer used for suturing/nerve repair
epineurium
Nerve fibers, which are axons, organize into bundles known as fascicles with each fascicle surrounded by the ________.
perineurium
Between individual nerve fibers is an inner layer of _______
endoneurium
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
Neurapraxia:
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
Axonotmesis:
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
Neurotmesis:
_______ 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
Level A Test
*_______ 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.
Neurapraxic
What medication can be used for neurapraxic injuries?
Methyl Prednisone dose pack for anti-inflamm
If tension free repair is not possible, ________ is mandatory
nerve grafting
The ___________ is preferred for nerve grafting since it most appropriately matches the nerve
diameter and the fascicular number and pattern of the Trigemminal nerve
Sural nerve
