Question: how long does it take for dental anesthesia to work?
Answer: After Novocaine is injected, you'll begin to feel numb after 5 to 10 minutes. The numbing sensation typically lasts 30 to 60 minutes. Since Novocaine by itself has a very short duration of action, it's often used in conjunction with epinephrine (adrenaline) to make the effects last a little longer.