What is mental nerve block?
A mental nerve block numbs parts of the face.
A mental nerve block is a type of anesthesia used for numbing parts of the face. This type of anesthetic nerve block is mainly used for wound repair to the lip and chin.
The sensory area of the mental nerve is a branch of the inferior alveolar nerve located on the face, below the lower lip, on the side of the chin. The mental nerve is a branch of the 5th cranial nerve (called the trigeminal nerve), which provides sensory input to the face.
The trigeminal nerve divides into the inferior alveolar nerve, and exits the jaw and enters the face through the mental canal (mental foramen) and supplies sensation to the skin of the chin and the mucus membranes of the lower lip.
This type of nerve block does not numb the teeth and is not used for dental procedures.
What is mental nerve block used for?
Mental nerve block is used for the following:
- To repair lacerations and wounds of the lower lip, especially if the cosmetic edge of the lip (vermillion border) is involved
- To repair lacerations and wounds to the soft tissue of the chin that extends from the lip
- To surgically remove facial tumors/lesions
- To relieve chronic nerve pain from shingles (postherpetic neuralgia)
How do you give a mental nerve block?
There are two ways to numb the mental nerve and perform a mental nerve block: through the mouth (intraoral) and outside the mouth (extraoral).
For a mental nerve block performed through the mouth (intraoral):
- Topical anesthetic is applied to the inner part of the lower lip and gums below the tooth line
- The doctor feels for the mental canal (foramen) on the side of the chin, on the jawline
- An anesthetic is injected into the area around the mental foramen using a small needle from inside the lower lip
- After a few minutes, the area of the mental nerve becomes numb and the procedure can be performed
For a mental nerve block performed from outside the mouth (extraoral):
- The skin over the chin is cleansed with antiseptic
- The doctor feels for the mental canal (foramen) on the side of the chin, over the jawline
- An anesthetic is injected through the skin of the chin into the area around the mental foramen using a small needle
- The doctor firmly massages the area for 10-15 seconds
- After a few minutes, the area of the mental nerve becomes numb and the procedure can be performed
For either the intraoral or extraoral approach, the local anesthetic’s (usually lidocaine) effect lasts between 30 minutes and two hours.
What are the risks and complications of mental nerve block?
Complications of mental nerve block can include the following:
- Bleeding
- Infection
- Needle fracture
- Intravascular injection
- Nerve damage (neurapraxia) secondary to direct injection into the mental foramen