The numbness after a dental filling typically lasts between 1 to 3 hours, but in some cases, it can persist for up to 5 hours or even longer depending on the type of local anesthetic used and individual factors such as metabolism and the injection site. Common anesthetics like lidocaine generally wear off within 1 to 2 hours, while others like bupivacaine can cause numbness for up to 8 hours. The numbness usually fades gradually, with feeling in the lips often returning first, followed by the tongue and cheeks.