How long does dental anesthesia last?
Depending on what anesthetics are used, how much is given, and how quickly your body metabolizes the drugs, how long the numbing sensation lasts can vary quite a bit. Lidocaine, the most widely used dental anesthetic, typically takes 3 to 5 hours to wear off completely. For surgical procedures like wisdom teeth extractions, some providers will use longer acting anesthetics like bupivacaine to help reduce post-operative pain, which can last for 5 to 12 hours.
Common Dental Numbing Times
- Commonly used Lidocaine: 3-5 hours
- Surgical procedures using bupivacaine: 5-12 hours
What impacts the duration of dental numbness?
- Type of anesthetic
- Amount given
- Your metabolic rate
- Where it was applied
Why does the dentist numb you up?
When you have dental work done, your dentist or dental hygienist wants to be sure you aren’t experiencing any pain or discomfort, so they will likely use a local anesthesia to numb the area being worked on. Many people dislike or are scared of needles and injections, but at most, the shot will only take a minute or two, and then you can be more relaxed knowing you aren’t going to feel any pain.
How does Novocaine work?
Local anesthetic agents are often called “Novocaine”, which was the first drug to be used for numbing for dental procedures. Most dentists stopped using Novocain before 1950 when better drugs came out, but the term has stuck around and is synonymous for almost anything used as a dental anesthetic. Now lidocaine is the most commonly used anesthetic for dental procedures.
Local anesthetics are injected into the tissue and work by “coating” the nerves to prevent them from sending pain signals to your brain. You will still be able to feel pressure, so if you are having a tooth pulled, you will feel pushing or tugging, but it should not hurt.
While you are numb you might have reduced motor control of the muscles in the area, but part of the difficulty with movement is just the lack of feeling. You will not have any cognitive impairment, so you are completely fine to drive and work after, although you will probably not want to talk a whole lot before the numbness wears off.
What does dental numbing feel like? What should I expect?
Injections are generally necessary to get your teeth numb, so you will probably feel a bit of a pinch when the needle goes in. Many dentists use a topical numbing gel to help reduce the discomfort at the injection site.
Although you want to get the shot out of the way as fast as possible, the more slowly the anesthetic solution is injected, the more comfortable it will be. It is also helpful to do things to distract yourself, like wiggling your fingers or toes on just one hand or foot. Even if you know you’re doing it as a distraction, your brain has difficulty concentrating on the two things at the same time.
When dental anesthetics begin to work, it usually starts with a tingling sensation in your lip or tongue, similar to how it feels when your foot “goes to sleep”. It generally takes a few minutes for the full effect to set in, and then your lip and/or tongue will feel like it is swollen or “fat”, even though it will still look normal.
If you are having a lower tooth worked on, your dentist usually needs to give a block injection towards the back of your mouth that will get the whole side of the jaw numb including that side of your tongue. While the area is numb you may have trouble drinking, speaking, and eating normally. Block injections are necessary on the lower because the nerve to those teeth runs inside of the jaw bone, so it has to be anesthetized farther back, before it enters that jaw.
If possible, it is preferable to avoid having both sides of the lower arch worked on at the same time because having your entire tongue and lower lip numb can be highly uncomfortable. It is not dangerous, but it can be unnerving because it feels like it is difficult to swallow.
If you are having an upper tooth worked on, the nerves can be anesthetized more individually, so you will have less collateral numbness. Unless you are having a front tooth worked on, which would cause your upper lip to be numb, you probably won’t notice much more than a dull sensation of the teeth and a little numbness in your cheek.
If you are still feeling pain after an injection for a dental procedure, do not be afraid to ask your dentist for more anesthetic. Generally the tissue is numb enough that you will not even feel an additional shot, and some people just need more anesthetic to get the job done, or the nerve may be in a slightly unusual position. There is a maximum dose for anesthetics, but it is usually at least 7 cartridges (unless you have a heart condition).
What are the different kinds of numbing?
Depending on what dental procedure you are having done, you may need kinds of anesthetics. Topical anesthetics are in gel or liquid forms and can get the gum tissue numb, but not the teeth. If you are getting your teeth cleaned and your gums are sensitive, a topical numbing gel may be sufficient to keep you comfortable without requiring injections.
If you are having fillings or crowns placed, your dentist will probably need to use a drill to remove the decayed portion of the tooth, and most often will need to use an injected local anesthetic to prevent pain. For a tooth extraction, you will most definitely want to have a local anesthetic.
Although not classified as anesthetics, for highly anxious patients, nitrous oxide (also known as laughing gas), anti-anxiety medications, or sedation dentistry are also options to get through needed dental work.
How can I make the numbing effects wear off faster?
- Drink lots of water! (Just be careful not to spill) Most dental anesthetics are processed through the kidneys, so drinking water helps flush everything out.
- Stimulate blood flow. Most anesthetics used for dental procedures have a vasoconstrictor that shrinks the blood vessels in that area so the numbing doesn’t wear off too quickly before the procedure is done. Increasing blood flow to the area can help make the drugs absorb more quickly, but you do not want to increase blood to the area if you’ve had a tooth extracted, or had an abscess that required a root canal. If you had a filling or crown done and want the anesthetic to process more quickly try:
- Massaging the area that is still numb (with clean hands)
- Applying heat with a warm compress
- Getting your heart rate up with a brisk walk or light exercise
What to do if numbness is prolonged:
If you have numbness that lasts more than 12 hours, contact your dental office. Prolonged numbness, known as hypoesthesia or paresthesia, is extremely rare, and it can last for a few days or even months, but almost always resolves. Dental anesthetics are very safe, but complications are possible with any procedure and any drug. Your dentist may want to prescribe a steroid to help decrease inflammation that may be contributing to the numbness.
