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Boil On Gum After Root Canal, Is That Normal?

Updated: Feb 6

If you notice a boil on the gums shortly after finishing the root canal, it means that the infection did not go away completely. Basically, the infection is still there because the treatment was insufficient in killing all of the bacteria. It usually means your tooth requires further root canal treatment with additional rounds of antibiotics and medication.

root canal x-ray with a gum boil

This article will explore what causes the gum boil even though you had a root canal. What you can do to get rid of it and also if it's possible for it to go away on its own.

Table of Contents:

What causes a gum boil after a root canal?

Gum boils form as a result of an accumulation of bacteria from an abscessed tooth. The purpose of a root canal is to remove the infection from within the tooth and sterilize it by eliminating all of the bacteria.

gum boil after root canal
gum boil after root canal

Unfortunately, there are times where some of the bacteria manage to survive and then they repopulate and grow in size to reform the tooth abscess. Basically the tooth goes through all of the stages of a tooth abscess again until it reaches the stage where a gum boil forms on the gums.

Reasons for residual bacteria after a root canal

Bacteria can occasionally survive through a root canal treatment because the disinfecting agent does not kill 100% of them and we're unable to test for the absence of bacteria.

Disinfecting agent not perfect

What your dentist uses to disinfect the canals of your tooth is sodium hypochlorite, which is basically Clorox bleach. Even according to the manufacturer themselves, the label specifically states that it kills 99.9% of germs.

Typically when we see this it does mean that it kills them 100% BUT there are times where it doesn't for whatever reason. Due to the off chance that it doesn't, they are required to reduce that number from 100% down to 99.9% for liability issues. This means that once in a while, it may not kill all of the bacteria in your root canal.

Testing for bacteria.

Your dentist does not have a way to definitively determine that all of the bacteria inside of your tooth is dead. We assume that most of them are gone after disinfecting it enough times.

However, there are times where bacteria are hidden away in areas of the tooth that we are unable to detect. If enough bacteria survive, the gum boil can reform once the bacterial population grows large enough. Once it does, it means that abscess on the gums has returned.

How do you get rid of a gum boil after a root canal?

The only way to get rid of the boil on your gums after the root canal is by redoing the root canal again but this time with twice the amount of disinfection. Basically your dentist will go back in there and redo the entire procedure. Then they will also place antibacterial medication inside of the tooth for a few weeks. After that they can finish the treatment by filling in the canal.

Step by step process of the procedure:

  1. Administer local anesthesia to numb the tooth.

  2. Redo root canal treatment.

  3. Disinfect the canals as much as possible with sodium hypochlorite.

  4. Place antibiotic medication inside the canals to kill the abscess.

  5. Leave medication for 1-2 weeks.

  6. Evaluate whether the boil on the gums is gone or not.

  7. If it is gone, you can finish the root canal by placing the root filling material.

  8. If it is not gone, you will have to repeat steps 3-6 until it goes away.

Alternatively, if the pimple on the gums does not go away even with disinfecting the tooth multiple times, the tooth may be hopeless. In that case, the only treatment option would be to remove the entire tooth via an extraction.

Will the gum boil go away on its own?

Unfortunately, infections, abscesses, and gum boils do not go away on their own. They are the result of bacteria accumulation within the tooth because it is infected. As long as the source of the infection, which is coming from within the tooth remains, it will continue to produce more bacteria and the abscess will grow in size.

This means that the pimple on the gums can get bigger. It can get big enough where the swelling will need to be drained. You'll notice this if you feel your face swell up.

Home remedies will not cure boils on the gum either. The most that they can do is temporarily relieve some of the tooth pain. The best thing to do would be to see a dentist to have it treated permanently.

Nonetheless if you are unable to do so or can't get an appointment, here are some methods you can try in the meantime:

  • Salt water rinse - salt is a natural antiseptic and can help slow down the spread of infection. It won't get rid of it but it'll at least keep the area clean.

  • Hydrogen peroxide rinse - this product can definitively kill bacteria and reduce the amount in your mouth. Just be aware that it is unable to reach the source of the infection so it is not a permanent cure.

  • Oregano oil - has antibacterial properties. You can give it a try to see if it helps. Put a drop on a cotton tip and swab the area or you can turn it into a rinse as well.

  • Thyme oil - similar to the oregano oil and can be used the same way.

  • Cold compress - the cold can numb the affected area thus providing tooth pain relief.

  • Over the counter pain medication - these always work but you can't keep taking them long term. You need to see a dentist as soon as possible.


To summarize, a boil on the gums after a root canal is NOT normal. It is an indication that the infection and abscess has returned. It means that you will need to have the tooth disinfected once again, which entails redoing the root canal and doubling up on the disinfection protocol.

That is the only way to make the pimple on the gums go away. If you simply leave it untreated, it can progress and make your face swell up. Home remedies will also have very little effect on these gum pimples. You must seek professional help if you notice a gum boil even if that tooth had a root canal!



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!

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