Numbness from a dental filling typically lasts 1 to 3 hours for the tooth itself, but the soft tissue numbness in your lips, tongue, and cheeks can persist for 3 to 5 hours. The exact duration depends on which anesthetic your dentist used, where the filling was placed, and whether the injection included a vasoconstrictor to extend its effect.
Your Dentist Probably Didn’t Use Novocaine
“Novocaine” has become a catch-all term for dental numbing, but actual Novocaine (procaine) has largely disappeared from dentistry. It was introduced in 1905 and became hugely popular in the U.S., but it carried a high potential for allergic reactions. Modern dental offices almost exclusively use amide-group anesthetics: lidocaine, articaine, mepivacaine, and bupivacaine. Lidocaine is the most widely used local anesthetic in dentistry today.
This matters because the anesthetic your dentist actually injected affects how long you stay numb. Lidocaine and articaine are the most common choices for fillings, and they produce similar durations of numbness. Bupivacaine lasts significantly longer and is typically reserved for more involved procedures.
Why Lower Teeth Stay Numb Longer
If your filling was on an upper tooth, your dentist likely used an infiltration injection, which deposits the anesthetic right next to the tooth. Upper jaw bone is more porous and trabecular, so the solution diffuses through it easily and wears off relatively quickly. You can expect soft tissue numbness in the range of 1 to 3 hours.
Lower back teeth are a different story. The lower jaw has thick, dense cortical bone that blocks anesthetic from diffusing through to the nerve. To get around this, dentists use an inferior alveolar nerve block, injecting the anesthetic near the nerve trunk farther back in the jaw. This numbs a much larger area, including the lower lip, chin, and half the tongue on that side, and the numbness tends to last longer, often 3 to 5 hours. The broader area of numbness is also why biting your lip after a lower filling is so common.
What Affects How Quickly It Wears Off
Several factors influence your personal timeline:
- Vasoconstrictor added: Most dental anesthetics are mixed with epinephrine, which constricts blood vessels at the injection site and keeps the anesthetic concentrated there longer. Without it, numbness fades faster but the anesthetic also wears off during the procedure more quickly.
- Amount injected: A small, shallow filling may need only one cartridge. A deeper filling or one close to the nerve may require more anesthetic, which extends numbness.
- Your metabolism: People with faster metabolisms, higher blood flow to the area, or smaller body size tend to clear the anesthetic sooner. Inflammation at the injection site can also change how the drug is absorbed.
- Which drug was used: Lidocaine and articaine have similar durations. Mepivacaine without a vasoconstrictor wears off fastest. Bupivacaine can keep soft tissue numb for over 7 hours.
Speeding Up the Recovery
If lingering numbness is inconvenient, there is one clinical option. An injectable reversal agent (sold as OraVerse) is FDA-approved to shorten lip and tongue numbness after anesthetics that contain a vasoconstrictor. It works by blocking the vasoconstriction from epinephrine, which allows blood to flush the anesthetic out of the tissue faster.
The time savings are meaningful. With lidocaine, the reversal agent cuts lip and tongue numbness by roughly 2 hours. With articaine, the reduction is closer to 2.5 to 3 hours. Not every office stocks it, and it’s usually an additional cost, so you’d need to ask before your appointment. Reported side effects are mild: soreness at the injection site, occasional headache, and rarely a temporary increase in heart rate.
Without the reversal agent, there isn’t much you can do to speed things up. Light activity and staying warm may marginally increase blood flow, but the effect is minor. The numbness simply has to metabolize on its own.
Eating and Drinking While Numb
Avoid eating anything and skip hot beverages until the numbness has completely worn off. The risk isn’t the filling itself (modern composite fillings set hard under the curing light before you leave the chair). The risk is to you. Without sensation, you can bite your cheek, tongue, or lip hard enough to cause real tissue damage and not feel it until the anesthetic clears. Hot drinks are particularly dangerous because you can scald the inside of your mouth without realizing it.
If you’re hungry and still numb, cool or lukewarm soft foods on the opposite side of your mouth are the safest option. Just be cautious, especially if a nerve block numbed your entire lower lip.
When Numbness Lasts Too Long
If you’re still numb after 5 to 6 hours, that’s on the outer edge of normal for a nerve block but not necessarily a problem. Give it until the next morning. If numbness, tingling, or a burning sensation persists beyond 24 hours after the anesthetic should have worn off, contact your dentist. This could indicate paresthesia, a nerve irritation caused by the injection itself rather than the anesthetic.
Paresthesia from dental injections is uncommon, and when it does happen, most cases resolve on their own within the first six months. Permanent sensory changes occur in roughly 0.12% of cases. The sensation is different from normal post-anesthetic numbness: instead of a uniform lack of feeling, paresthesia often presents as partial numbness mixed with tingling or burning in the lip, chin, or tongue. In rare cases, onset can be delayed by days or even weeks after the procedure rather than being noticed the same day.