Benzocaine is a local anesthetic. If it enters the esophagus, it can have an anesthetic effect of the airways, increasing the risk of inhalation of saliva.

The most common anaesthetic gases I see used are Sevoflurane and Desflurane.

Anesthesia: Partial or complete loss of sensation, with or without loss of consciousness, as a result of disease, injury, or administration of an anesthetic agent, usually by injection or inhalation.

Local anesthetic is safe if the dosage is not excessive. When the area to aspirate is extensive, the high doses of local anesthetic required are toxic and may cause serious complications. In these cases, a general anesthetic (by inhalation) guarantees the best results, reducing risks to a minimum. In any case now the client can return home after the surgery.

halothane (a nonflammable inhalation anesthetic that produces general anesthesia; used along with analgesics and muscle relaxants for many types of surgical procedures)