The lingual nerve is a part of the mandibular branch of the trigeminal nerve (V3). The lingual nerve provides general sensory information to the floor of the mouth, the lingual mucosa, as well as the anterior 2/3rds of the tongue.

What makes the lingual nerve so special?

The lingual nerve has two ‘special’ roles – it caries fibers from the facial nerve (VII) to offer special sensory information such as the perception of taste, and also contains parasympathetic fibers from the facial nerve to the submandibular ganglion (which is partially responsible for the salivary secretions). If this nerve were damaged, a patient could experience a loss for the majority of their tastes.

When would we need to anesthetize the lingual nerve?

Mandibular extractions may require anesthetizing the lingual nerve. This is because the lingual soft tissue may not be affected by facial/ buccal infiltration. During inferior alveolar nerve blocks, the lingual nerve may be anesthetized as it is in close proximity. However, this may not always be the case – further anesthetizing via the lingual nerve may be indicated.

Can we damage the lingual nerve?

The lingual nerve can be damaged during extraction procedures, or by damage to the floor of the mouth. Studies show that, when a gingival flap is required, a flap retraction poses 3.4 times increased risk of lingual nerve damage during extraction of mandibular third molars when lingual flap is retracted but the nature of damage is reversible. There are studies with evidence that provide modified flap designs that allow for protection of the lingual nerve during extractions that require surgical treatment.

To summarize:

• The lingual nerve provides general sensory information to the lingual mucosa
• The nerve is responsible for taste in the anterior 2/3rds of our tongue
• Anesthetizing the nerve should be attempted during an inferior alveolar nerve block, though may not be succesful
• Special care should be given to the lingual nerve when extracting third molars

References:

(n.d.) Trigeminal and Associated Nerves. Dr. B. A.T. Still Missouri School of Dentistry and Oral Health.

Shad, S., Shah, S. M. H., Alamgir, & Abbasi, M. M. (2015). FREQUENCY OF LINGUAL NERVE INJURY IN MANDIBULAR THIRD MOLAR EXTRACTION: A COMPARISON OF TWO SURGICAL TECHNIQUES. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/26721012.