Nerves of the teeth and mouth: trigeminal (V) and facial (VII)

What it is

Sensation from the teeth and oral tissues comes from the trigeminal nerve (cranial nerve V). Its maxillary division (V2) supplies the upper teeth through the superior alveolar nerves and the palate through the greater palatine and nasopalatine nerves. Its mandibular division (V3) supplies the lower teeth through the inferior alveolar nerve, the lower lip and chin through the mental nerve, the anterior two-thirds of the tongue through the lingual nerve, and the muscles of mastication. The facial nerve (VII) moves the muscles of facial expression and, through the chorda tympani that travels with the lingual nerve, carries taste from the anterior tongue.

Clinical anatomy

• V2: posterior, middle and anterior superior alveolar nerves to the upper teeth; greater palatine and nasopalatine to the palate.
• V3 sensory: inferior alveolar (lower teeth), mental (lower lip, chin), lingual (anterior two-thirds of the tongue, floor of mouth), long buccal (cheek gingiva of lower molars).
• V3 motor: masseter, temporalis, medial and lateral pterygoids, and others.
• VII: muscles of facial expression; chorda tympani (taste of anterior tongue, submandibular and sublingual secretion).
• Glossopharyngeal (IX): sensation and taste of the posterior third of the tongue.

Clinical correlation

• Pain from a lower molar is often felt in the ear or temple (shared V3 territory); upper and lower pain can be confused.
• The lingual nerve lies just inside the lower third molar: injury during extraction causes numbness and altered taste on that side of the tongue.
• An inferior alveolar block injected too far back can reach the parotid gland and cause a temporary facial (VII) palsy that resolves when the anaesthetic wears off.
• Trigeminal neuralgia gives electric-shock pain in V2 or V3 triggered by touch or chewing and is often first taken to the dentist.

Next step / Initial management

• Facial pain with normal teeth: think of referred pain, trigeminal neuralgia, sinusitis, temporomandibular disorder and, in older adults, giant cell arteritis.
• Numbness after dental surgery: document the area and refer back to the surgeon early; most recover, but early assessment matters.
• Facial palsy after a dental injection that resolves within hours needs no treatment beyond eye protection; one that persists needs review as for any facial palsy and referral.

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Elsewhere in DurgiPedia

• Facial nerve: course, branches and site of the lesion
• Taste and smell

Connections

← All of dentistry

Educational content; it does not replace assessment by a dentist or doctor and is not a clinical instruction. For facial or neck swelling with difficulty swallowing or breathing, a knocked-out tooth or bleeding that will not stop, go to an emergency department at once.

Sources: Neuroanatomy, Cranial Nerve 5 (Trigeminal) (StatPearls Publishing (NCBI Bookshelf), 2024); Anatomy, Head and Neck, Maxillary Nerve (StatPearls Publishing (NCBI Bookshelf), 2023); Anatomy, Head and Neck, Mandibular Nerve (StatPearls Publishing (NCBI Bookshelf), 2023); Anatomy, Head and Neck: Alveolar Nerve (StatPearls Publishing (NCBI Bookshelf), 2023); Anatomy, Head and Neck, Lingual Nerve (StatPearls Publishing (NCBI Bookshelf), 2023); Facial Nerve Anatomy and Clinical Applications (StatPearls Publishing (NCBI Bookshelf), 2023).

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