What is a common complication of a PSA nerve block?

The common complication associated with a PSA (posterior superior alveolar) nerve block is hematoma formation. During the administration of the PSA nerve block, the needle is inserted near the pterygoid plexus, which is a network of veins. If the needle inadvertently punctures this plexus, it can lead to the bleeding and subsequent formation of a hematoma, which may cause swelling and discomfort in the area.

While the other options may represent complications that could occur in specific circumstances, they are not as directly associated with the PSA nerve block. For instance, drooping of the face and facial paralysis are more commonly related to complications from anesthetic agents affecting the facial nerve rather than the site of a PSA block. Pterygoid plexus penetration could occur, but it is the resultant hematoma that is recognized more frequently as a complication rather than the act of penetration itself. This makes hematoma formation a significantly relevant concern for dental practitioners when administering a PSA nerve block.