What is a necessary synonym for "shot" in a dental context?

In the context of dental procedures, a "shot" typically refers to an injection given to the patient to numb an area of the mouth before a dental treatment. The preferred synonym that aligns with this meaning is "injection."

While "numbing medicine" refers to the substance that numbs the area, it does not specifically indicate the method by which that substance is administered. In contrast, "injection" directly implies the act of delivering the anesthetic agent via a syringe, which is essential for providing local anesthesia during dental work.

The other options also do not fit appropriately as synonyms for "shot." A "vaccine" is generally related to immunization and not relevant in a dental setting for anesthesia, while a "prescription" refers to a written order from a dentist for a medication, which also does not capture the specific act of administering anesthesia through a shot. Thus, "injection" is the necessary synonym in this dental context.