How long does your mouth stay numb after anesthesia at the dentist?

Local anesthetics, Depending on which one was used and whether a vasoconstrictor was included, as well as the amount given, can have a wide range of anesthesia times. Some can dissipate after only 30 minutes, while others can last 10-12 hours. While numb, stick to a non-chew, liquid to puree diet so that you avoid the chance of injuring the soft tissue of your lip, tongue or cheek.
Varies. Some local anesthetics can last up to 15 hours. If you have concerns ask your dentist about your case.