When Does Novocaine Wear Off?

Updated: Oct 15

It has been over an hour since you've finished your dental filling appointment but you're still numb. How long does novocaine last and how long should it last? Is it suppose to last the entire day? Well hopefully there is something you can do to make it wear off faster.





What is novocaine?

Novocaine is a local anesthetic that was first synthesized in 1905 and its generic drug name is procaine. It was initially marketed for medical use for surgeons, however dentists found it be far more useful and thus, became the preferred tooth filling anesthesia.


How does novocaine work?

When novocaine is injected near nerves, it works by blocking sodium channels so that the nerves can't send pain signals to the brain. This allows your dentist to drill into your tooth without you feeling any pain. If you try to do any dental fillings without numbing, you wouldn't have a very pleasant experience.


Symptoms of getting novocaine

When your dentist gives you the novocaine shot, the first symptom that you will feel is a small sharp pinch. Then you will feel a slight burning sensation, which is due to the acidity of the anesthesia. After a couple of seconds, you shouldn't feel any more pain from the numbing.


After about 1-4 minutes, your tooth will feel numb first and then the soft tissue of your face will get numb second. The soft tissue includes your cheeks, lips, and tongue.


What the numbness feels like on your face is similar to if your face fell asleep. It'll feel like it is large and swollen. Another similar sensation is if you've ever had your legs fall asleep on you and you can't feel your legs. The only difference is that you're feeling that same sensation but around your face.


Do dentists still use novocaine?

Modern day dentists actually no longer use novocaine after the discovery of a new type of local anesthetic, Lidocaine. This new anesthetic was discovered in 1946 and has mostly replaced novocaine in virtually all dental offices across the globe.


However, the general populace has gotten so use to calling the dental anesthesia "novocaine" that we just continue to use that term. With that being said, even though we are calling it novocaine, what we are actually referring to is usually lidocaine but there are other types of dental anesthetics as well. But basically, this is what your dentist uses to numb your mouth.


Here is a picture of lidocaine, the anesthetic that the vast majority of dentist use:

lidocaine


How long till novocaine wears off?

On average, novocaine can wear off in as little as 3 hours but also last as long as 5 hours. According to one study, the difference in time largely depends on the type of injection that was used, local infiltration vs nerve block. In addition to that, the tooth filling anesthesia also wears off faster for the tooth when compared to the soft tissue.


Local infiltration - when the injection is given in an area near the nerve endings

  • The time of onset: Less than 2 minutes

  • Average pulp anesthesia time: 60 minutes

  • Average soft tissue anesthesia time: 2.5 hours


Nerve block - when the injection is given near the trunk of the nerve

  • The time of onset: Between 2-4 minutes

  • Average pulp anesthesia time: 90 minutes

  • Average soft tissue anesthesia time: 3-3.25 hours

What this means is that the novocaine will last longer when you're given a nerve block but it will wear off faster if you're given a local infiltration. It also means that the numbing wears off faster for your tooth when compared to the gums and soft tissue. Nonetheless, those numbers are still averages because how long the numbing can last varies depending on a multitude of other factors as well.


What else affects how long novocaine lasts?

How long novocaine can last will depend on a couple of factors such as the dose, individual genetics, presence of infection, and amount of epinephrine in the anesthetic.

  • Dose. The higher the dosage or the greater the amount of anesthetic you receive, will make the numbing last longer. The lower the dosage and the less novocaine you receive, the faster the numbing will wear off.

  • Individual genetics. Everyone processes novocaine at varying rates, similar to how some people can process alcohol faster. Some people can even have a rare disease called pseudocholinesterase deficiency, which causes novocaine to last even longer than the usual 3-4 hours.

  • Redheads. People with the genetic trait for bright red hair are typically more difficult to numb. They also do not stay numb for as long.

  • Presence of infection. If you have an active infection, a lot of times the novocaine won't be as effect. This makes the anesthesia not last as long and the effects won't be as profound.

  • Amount of epinephrine. When epinephrine is added to a local anesthesia, it improves the depth and duration of anesthesia. If you increase the amount of added epinephrine it will also increase the effects. Therefore, novocaine with epinephrine will take longer to wear off vs one without epinephrine.


What does not affect how long it lasts

The type of dental procedure has no effect on how long the novocaine can last. This means that the numbness for a filling procedure will last the same amount of time as a dental crown or even a tooth extraction. The numbness will wear away at the same rate regardless of the dental treatment.


How to make novocaine wear off faster?

Having a numb face for hours isn't the most pleasant experience but thankfully there are techniques to make it go away faster. Here are some home remedies to make novocaine wear off faster.


Increase blood flow to the area

You want to do activities that will increase the amount of blood flowing to the numb area so that it can take the anesthesia away for processing. The reason is because if the blood does not move from the area, the anesthetic will just keep the area numb.

  • Massaging your face will help bring blood flow to the numbed parts of your face.

  • Doing some light physical exercise will also get your heart pumping and help circulate blood to the numb area.

  • Opening and closing your jaw every couple of minutes will help with the blood circulation as well.

Apply a warm compress

Using a warm compress on the numbness will increase muscular blood flow. Studies have shown that local heating of an increase in 4 degrees celsius will increase muscle blood flow by 45% to the area.


Ask your dentist for a numbness reversing agent

Your dentist may have a product called OraVerse, which can help reduce the length of numbness by approximately 50%. Oraverse will make the novocaine wear off in about half the time that it usually takes. The only downside is that to receive this product, you would require a second injection because it is delivered in a dental needle.


Side effects effects of using novocaine

Side effects are pretty rare when using novocaine and these are the symptoms that you may experience.

  • Prolonged numbness

  • Dizziness

  • Headches

  • Pain near injection site

  • Muscle twitching

  • Methemoglobinemia - cyanosis of the nail beds and lips, fatigue and weakness. This is a dangerous condition which requires your provider to give you oxygen.

Last but not least, patients who've had a history of hypersensitivity to local anesthetics of the amide type should be cautious of using it. You could potentially trigger an allergic reaction from the anesthetic.



Takeaway

To summarize, it takes approximately 3-5 hours for novocaine to wear off but there are a lot of factors, which can affect how long the numbness can last. There are home remedies, which you can incorporate to make it wear off faster.


If you have any questions, please feel free to schedule a consultation with one of our restorative dentists in long island city dentist!

David Chen 200 x 200.jpg

About the author: Dr David Chen, DDS

Hello, I'm Dr Chen and I'm an actively practicing dentist in Long Island City, NY. I graduated from Columbia University College of Dental Medicine in 2016 but prior to going to dental school I was already working in the dental field. It's been more than a decade since I first got to know dentistry and let me tell you, time flies by quickly. Since then I've developed a fondness for writing, which is how this all got started!

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Medical Disclaimer:

This blog is purely meant for information purposes and should not be used as medical advice. Each situation in your mouth is unique and complex. It is not possible to give advice nor diagnose any oral conditions based on text nor virtual consultations. The best thing to do is to go in person to see your dentist for an examination and consultation so that you can receive the best care possible.

The purpose of all of this oral health information is to encourage you to see your dentist and to inform you of what you may expect during your visit. Due to the unfortunate nature of dentistry, there isn't really any true home remedies that will get rid of dental problems. Roughly 99.99% of them require in-person intervention by a healthcare professional.

Hint: That is the reason why you can't eliminate seeing dentists in your life!