What does the posterior superior alveolar nerve supply?

The posterior superior alveolar nerve is responsible for supplying sensory innervation to the maxillary molar teeth, specifically the maxillary first, second, and third molars, which correspond to teeth numbers 8, 7, and 6 in the dental notation. However, it is important to note that the mesio-buccal root of the maxillary first molar (tooth number 6) receives its innervation primarily from the middle superior alveolar nerve or the anterior superior alveolar nerve in some cases, which is why the correct choice specifies that it supplies all of these teeth except for the mesio-buccal root of the first molar.

The first option accurately describes this anatomical supply, making it the correct answer. Understanding which specific roots and teeth are innervated by the posterior superior alveolar nerve is crucial for dental professionals when considering local anesthetic techniques or managing dental pain.