Which of the following injections is most appropriate for the maxillary first molar?

The appropriate injection for achieving anesthesia of the maxillary first molar is the PSA (Posterior Superior Alveolar) nerve block. This block targets the PSA nerve, which innervates the maxillary molars (with the exception of the mesiobuccal root of the maxillary first molar in some cases) and the surrounding buccal soft tissues. By administering the PSA nerve block, dentists can effectively achieve profound anesthesia for procedures involving the maxillary molars, making it the ideal choice for this specific tooth.

Other injection options may not provide sufficient coverage for the maxillary first molar. For instance, the MSA (Middle Superior Alveolar) nerve block typically covers the maxillary premolars and the mesiobuccal root of the first molar but may not adequately anesthetize the entire first molar. The Greater palatine nerve block primarily targets the palatal tissues and does not achieve anesthesia for the tooth itself. Lastly, the buccal nerve block focuses on the buccal soft tissues around the molar but does not provide direct anesthesia to the tooth’s pulpal tissues. Therefore, the PSA nerve block is the most effective and appropriate choice for ensuring complete anesthesia of the maxillary first molar