How long will the anesthesia effect last after a cavity filling?

A few hours : The duration of local anesthesia varies with the type of anesthesia given. Typically, the effect lasts from 2-4 hours, but in many people it can last for up to half the day. You may speak to your dentist for the option of having the length of anesthesia increased or decreased by the type of numbing agent they give you.

It depends: On the type of local anesthetic that the dentist uses. Some last about an hour while others may last up to 12 hours. Discuss with your dentist.

Varies: Some local anesthetics wear off within 30 minutes, while other are specifically designed to be active for up to 20 hours. It depends on the type and location of the drug. Talk to your anesthesiologist or dentist about medications that they will use.