Mandibular third molar

Study entry

Location

Socket of the alveolar part of the mandible, at the end of the arch, next to the ramus of the mandible.

Structure

The last tooth to erupt and the most variable: the crown has three to five cusps and the roots are usually short, curved and fused. It may be absent. The 3D model does not include this tooth. It erupts between 13 and 25 years.

Neighborhood

It lies at the base of the ramus of the mandible. The inferior alveolar nerve runs close to the roots, and the lingual nerve passes right against the lingual surface of the bone in this region.

Blood supply

Inferior alveolar artery, branch of the maxillary, which runs in the mandibular canal and gives a branch to each root; the veins accompany the artery.

Innervation

Inferior dental plexus, formed by the inferior alveolar nerve (CN V3), which runs in the mandibular canal.

Lymphatics

The lymphatic vessels of the tooth and gum drain mainly into the submandibular lymph nodes.

Clinical

It is the tooth that most often stays retained (impacted) for lack of space, with pain, infection (pericoronitis) and caries in the second molar. Extraction can injure the inferior alveolar nerve (tingling in the lip and chin) or the lingual nerve (loss of sensation and taste on the tongue).

Source: cap. 8, «Dientes»; tabla 8-13 B (erupción de los dientes permanentes)

Other structures in this region

• Maxillary central incisor
• Maxillary lateral incisor
• Maxillary canine
• Maxillary first premolar
• Maxillary second premolar
• Maxillary first molar
• Maxillary second molar
• Maxillary third molar