Final answer:
The Posterior Superior Alveolar nerve (PSA) is NOT affected by the infraorbital nerve block, as this block primarily anesthetizes the midface region, whereas the PSA supplies the molar teeth and associated gingiva, which are more posterior.
Step-by-step explanation:
The infraorbital nerve block is a common procedure used in dentistry to anesthetize the midface region. This nerve block affects several nerves:
- Anterior Superior Alveolar nerve (ASA)
- Middle Superior Alveolar nerve (MSA)
- Posterior Superior Alveolar nerve (PSA)
- Infraorbital nerve (IO)
Among the options provided, the answer to which nerve is NOT affected by the infraorbital nerve block is the PSA, since it is not typically anesthetized by this block; the PSA nerve supplies the molar teeth and the associated buccal gingiva, which are generally more posteriorly located than the midface region affected by the infraorbital nerve block.