How long does it take for novocain (procaine) to wear off usually ?

1 1/2 - 2 hours: Length of anesthesia can vary depending on a variety of factors.

Average is 2 hours: To be precise, novocaine is no longer in use. Lidocaine is most popular anesthetic used and the numbing effect lasts about 60 minutes on the tooth and about 2 hours on soft tissue like lips and tongue. Other anesthetics that dentists use may last from 45 minutes to 8 hours depending on the need and situation.

Reversal agent: There is now an injection that can be given at the end of an appointment that actually reverses the numbness immediately. It is relatively expensive, and i like the fact that the numbness lingers during the immediate post treatment period. Nsaid administration also insures post injection comfort.