An 18 year old patient attends for the lower left molar restoring, by preparation for a crown, to anaesthetise the tooth and buccal gingivae which pair of nerves would achieve this?

• A. Mental and incisive nerves
• B. Long buccal and mental nerves
• C. Inferior alveolar and infraorbital nerves
• D. Inferior dental and long buccal nerves

Answer: (D)

The lower molar and its buccal gingiva are supplied by two separate nerves in the mandible. The tooth itself gets its sensory innervation from the inferior alveolar (inferior dental) nerve; blocking this nerve numbs the pulpal tissue of the lower molar. The buccal gingiva over the lower molars is supplied by the long buccal nerve; blocking this nerve desensitizes the buccal gingiva around those teeth. The mental nerve, a branch of the inferior alveolar nerve, serves the chin and lower lip and the anterior buccal gingiva, not the molar region, so it wouldn’t adequately cover the molar buccal tissue. The infraorbital nerve is a maxillary division nerve and irrelevant for the lower arch. Therefore, anesthetizing the tooth and its buccal gingiva requires blocking the inferior dental (inferior alveolar) nerve and the long buccal nerve.