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

2-3 hours: Most of the time it takes 2-3 hours for novacaine to wear off. Sometimes it can seem a bit longer. There are some brands that last twice as long.

Depends on Type: Short acting will last 1-3 hrs medium will typically last 2-4 hrs and long acting can be 8-12 hrs.

It varies.: Novocaine is rarely used today. The most common local anesthetic is lidocaine, and the most common formulation is packaged with epinephrine. Lidocaine with Epinephrine will usually provide deep anesthesia to the nerve of a tooth for 45 minutes and for the soft tissue, lips, gums, etc, for twice that. Anesthetic without Epinephrine wears off quicker. Some anesthetics, like marcaine, can last hours.