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Causes of Gum Boils

Updated: Apr 19, 2023

A gum boil is a progression in the stages of tooth decay and consequently that makes decay one of the most common causes of it. That's not to say that it is the only cause because there are a couple of other conditions, which can result in a boil on the gums as well (pimple on the gums).

gum boil (dental abscess)
gum boil (dental abscess)

This article will cover all of the possible causes and what you can do to make that pimple on the gums go away. Depending on the exact cause, the treatment may differ so there isn't a one size fits all approach to dealing with this condition.

Dental conditions which may cause a gum boil to form:

Pimple on the gums as a result of tooth decay

Tooth decay when left untreated will grow and progress through the stages of tooth decay and eventually form a gum boil. It all starts as a small cavity in the enamel which progresses into the dentin and finally into the pulp.

human tooth anatomy
Credit: KDS4444

Once it reaches the nerve, it will travel down to the tip of the root and form an abscess, which slowly eats through the bone. The pimple that you see on the gums is basically the tooth abscess that has made its way through the bone and into the oral cavity.

It may seem and sound harmless but that boil on the gums is a fully developed dental abscess. In other words, you should seek treatment for it sooner rather than later.

Treatment for how to get rid of it

Since it is the result of decay that has infected the nerve of the tooth, in order to make this pimple go away, you will need to treat the infected nerve. Therefore the source of the infection actually stems from within the tooth rather than from the boil on the gums. Simply trying to pop it won't get rid of the infection.

The only way to eliminate this abscess is by getting a root canal from your dentist. The procedure involves extracting the unhealthy nerve from the tooth and then placing an antibiotic medication within the canals to ensure that all of the bad bacteria have been eliminated.

What to expect:

  1. Apply numbing cream.

  2. Administer Lidocaine (local anesthetic).

  3. Excavate all of the cavity.

  4. Extirpate the infected nerve.

  5. Flush out the entire canal with sodium hypochlorite.

  6. Place calcium hydroxide (antibiotic medicament) inside of the canal.

  7. Place a temporary filling.

  8. Return 2 weeks later and disinfect the tooth once more.

  9. Place a root canal filling material.

  10. Now you're ready for the dental crown procedure.

Once the root canal is completed, the tooth will look like it has white lines going through it. Those white lines are the filling material on the x-ray and is what signifies to you that the nerve has been successfully removed.

completed root canal on x-ray

There is no home remedy known to mankind that will allow you to get rid of the infected nerve. The reason is because it is a physical process that requires someone to manually extract the nerve. In other words, the only person who can treat this condition would be your dentist.

Gum boil from a fractured tooth

These gum pimples can also form as a result of a fracture within the tooth. What we often find is that these teeth have already had a root canal on it, which means that the infected nerve was already removed. However, it seems to have a gum boil that keeps coming back.

Whenever we see a boil on the gums that doesn't seem to go away, we need to be suspicious of a root fracture. That is something which we cannot see with our naked eyes because the root is embedded within the bone. The only way to visualize it is by taking a CBCT x-ray, which is basically a 3D version of the normal one that we take.

The image above is of a radiology report from a CBCT scan of a fractured molar. The mesial surface of the distal root appears to have cracked. So, that is the apparent cause for the pimple on the gums.

Treatment for how to get rid of it

Unfortunately, for a fractured tooth the only treatment for it would be an extraction. Yes, it means that you need the entire tooth removed in order for the gum boil to resolve whenever it is a result of a crack in the tooth.

The reason is because your dentist is unable to repair root fractures. It is physically impossible to re-attach pieces of your root in this manner, thus your only option is tooth removal and then replace the missing tooth with an implant.

What to expect:

  1. Apply numbing cream and local anesthetic.

  2. Cut the periodontal ligaments to release the tooth.

  3. Elevate it with an elevator.

  4. Grab and extract the tooth with forceps.

  5. Irrigate the socket to remove any debris.

  6. Place stitches if needed.

Root canal treated tooth with a re-infection

A gum boil on a root canal treated tooth doesn't always mean that it is fractured and beyond repair. It could mean that the nerve got re-infected. The pimple will reform on the gums because the abscess has returned.

Despite the bad news, it is better news than a fracture because the tooth can be retreated with another root canal. As long as you redo it and clean the tooth out once more, the abscess should resolve within a week or two.

Treatment for how to get rid of it

The procedure would be the same as doing the root canal the first time. You'll definitely need to be numb for it because we don't want you to be in pain. Your dentist will then remove the old root canal filling and clean out the tooth once more.

They'll most likely place some antibiotics within the canals to ensure that all of the bacteria have perished. Once the pimple disappears from the gums, your dentist can refill the tooth once more.

Just as an interesting piece of information, most of the time when the root canal specialist goes back into the tooth to retreat it, they'll often find that the cause of the infection was actually a missed nerve. This is most likely on molar teeth because sometimes they can have extra nerves.

Two root canals on molars with 3 nerves each
Two root canals on molars with 3 nerves each

Most of the molar teeth in your mouth will have about three nerves. The x-ray above shows two upper molars that had root canals completed. Sure enough if you count the root canal filling material, there are 3 in each of the molars.

Here is an example of a molar with extra nerves. You can see five canals in this special molar!

molar with 5 nerves

That can be quite a surprise to most people because if you have extra nerves and it wasn't removed, of course the infection will return! Its because it was never completed cleared out to begin with and that is the reason why you have the boil on your gums.

Severe trauma to a tooth can result in a gum boil

You may be surprised but a tooth that has sustained trauma can form a pimple on the gums. If it gets hit hard enough, the tooth can die and eventually form an abscess at the tip of the root which eats through the bone to form the boil.

nerve infection from trauma

The x-ray above is of a front tooth which has formed an abscess. There is no cavity on the tooth at all but yet the tooth has died. The most likely reason is that the tooth has sustained trauma, which caused it to die.

Treatment for how to get rid of it

The treatment for this would be to get rid of the infected nerve by doing a root canal on it. The process is the exact same as a tooth which forms a boil due to tooth decay. Even though this one does not have decay, the procedure is still the same in order to get rid of the infection.

What to expect:

  1. Apply numbing gel and Lidocaine.

  2. Extract the infected nerve.

  3. Disinfect the entire tooth with sodium hypochlorite.

  4. Place antibiotics inside of the tooth.

  5. Place a temporary filling.

  6. Return 2 weeks later and disinfect the canals once more.

  7. Fill the canal with gutta percha.

  8. Now you're ready for the dental crown procedure.

Completed root canal
Completed root canal

Final Thoughts

There can be multiple reasons that your tooth can form a gum boil but the most common one is from tooth decay. If the decay is left untreated and grows big enough, it can result in an abscess at the root tip, which leads to a gum pimple.

Regardless of what the exact cause of it is, you will need to have this condition treated because the pimple is essentially a tooth abscess. It is not wise to leave an active abscess in your mouth untreated. That is not good for your oral health nor your overall health.

You need to seek professional dental help as soon as possible if you notice this small swelling on your gums. It is not a harmless condition even though it may seem like it.



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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