The upper teeth and gums are supplied by, the superior and posterior alveolar branches of the maxillary nerves. The labial surface of the gums receives additional supply through the infraorbital nerve, and the lingual surface from the nasopalatine and greater palatine nerves. The inferior teeth and gums are supplied by the inferior alveolar branch of the mandibular nerve, as it passes through the mandibular canal. The labial surface receives additional supply from the buccal and mental nerves, and the lingual surface from the lingual nerve. The incisors receive bilateral innervation.
The upper teeth and lower front teeth (figure 31a,b) are anesthetized by local infiltration of the adjacent gums, the anesthetic diffuses to the alveolar branches of the maxillary and mandibular nerves. The inferior alveolar (dental) nerve is anesthetized as it enters the mandibular canal. Place your thumb over the retromolar fossa and direct the needle above it, passing posteriorly and laterally for 1.5 cm along the medialside of the ramus of the mandible (figure 32). The lingual nerve passes just medial to this site and crosses the root of the third molar tooth; an inferior dental block thus also produces anesthesia of the anterior two- thirds of the tongue.