Final answer:
A PSA (Posterior Superior Alveolar) nerve block is needed to anesthetize the maxillary posterior teeth. It specifically numbs the upper molar teeth and is injected near the maxillary tuberosity. Lidocaine, a common anesthetic, acts as a sodium channel blocker to prevent the transmission of pain during the procedure.
Step-by-step explanation:
To anesthetize the maxillary posterior teeth, a PSA (Posterior Superior Alveolar) nerve block is used. This nerve block is administered to numb the molar teeth in the upper jaw (excluding the third molars, which are often anesthetized by the Greater Palatine nerve). The anesthesia is injected near the maxillary tuberosity, affecting the PSA nerve that innervates the maxillary sinus, maxillary molars, and associated bone and overlying soft tissue.
The IA (Inferior Alveolar) nerve block, choice 'a', is primarily used to numb the mandibular teeth, not the maxillary teeth. The Mandibular foramen, the Lingula, and substances like lidocaine, play vital roles in blocking the transmission of nerve impulses during dental procedures, making procedures like tooth extractions painless.
Anesthetics such as lidocaine work by being sodium channel blockers which prevent nerve impulses that convey pain from being transmitted, ensuring that the dental procedure can be performed without causing discomfort to the patient.