In some patients, which root of the maxillary first molar may receive pulpal anesthesia with an MSA block?

In some patients, which root of the maxillary first molar may receive pulpal anesthesia with an MSA block?

• A. MB (mesiobuccal) root
• B. Distobuccal root
• C. Palatal root
• D. Lingual root

Answer: (A)

The MSA block targets the middle superior alveolar nerve, which often provides innervation to the premolars and, in many people, to the mesiobuccal root of the first maxillary molar. Because of anatomical variation, that MB root can fall within the MSA distribution, so pulpal anesthesia of this root may be achieved with an MSA block in some patients. The other roots—distobuccal, palatal, and lingual—are typically supplied by different nerve branches (PSA, greater palatine, or lingual-related fibers) and are not consistently reached by the MSA block, so they’re not reliably anesthetized by it alone.

The MSA block targets the middle superior alveolar nerve, which often provides innervation to the premolars and, in many people, to the mesiobuccal root of the first maxillary molar. Because of anatomical variation, that MB root can fall within the MSA distribution, so pulpal anesthesia of this root may be achieved with an MSA block in some patients. The other roots—distobuccal, palatal, and lingual—are typically supplied by different nerve branches (PSA, greater palatine, or lingual-related fibers) and are not consistently reached by the MSA block, so they’re not reliably anesthetized by it alone.