Gum Boil vs Abscess, What’s the Difference?

Written & Reviewed by Dr David Chen

We’re not intentionally trying to rain on your parade, but a gum boil is a type of dental abscess. Well, to be more precise it is an oral manifestation that is an extension of a periapical abscess.

What does that all mean you say? If you’re asking, we’ll oblige.

There’s no difference

People often find a gum boil in their mouth and automatically assume that it’s an innocent pimple on the gums. It looks spherical in shape and is located on the gums and not the tooth. Therefore, the thought that it is an abscess rarely if ever crosses their mind.

However, if you understand the etiology of a gum boil, you’ll know that it is actually a tooth abscess in disguise. That gum pimple is a tell-tale sign of a periapical abscess and the correct dental terminology for it is a parulis. The parulis is technically the orifice of a sinus tract that leads directly to the abscess around the tip of the infected tooth root.

Gum boil with sinus tract - drawing
gum boil with sinus tract

The diagram which we’ve drawn above is to provide you with an idea of what we’re talking about. The takeaway point is that there is a sinus which connects the periapical abscess with the gum boil.

Therefore if you notice a gum boil in your mouth the first thought that should cross your mind is that you’ve a tooth abscess. You should schedule an appointment with your dentist immediately to figure out which tooth is abscessed.

Clinical evidence of it being an abscess

If you present to the dentist with a gum boil, they will take a periapical x-ray and perform a sinus tract tracing. Both of these are diagnostic tools which they use to pinpoint the abscessed tooth.

What a gum boil looks like on a PA x-ray

A tooth with a pimple on the gums will show a large radiolucency around the root tip of the infected tooth. What that looks like is a sizable black area surrounding the root tip.

That radiolucent area surrounding the tip is what we call a periapical abscess which is an accurate description of what it is.

  • “Peri” means around and “apical” means apex of the root.
  • It is indeed an abscess because they show up as radiolucencies on x-rays.

How to read x-rays:

  • Radiopaque – white objects on the x-ray which signifies how solid it is.
  • Radiolucent – dark objects on the x-ray which signifies space, emptiness, or less solid.

Essentially when you start seeing radiolucent areas within objects that are supposed to be radiopaque, it means it is becoming less solid. In the case of a gum pimple, the bone which is solid becoming less solid can only mean one thing, an abscess eating through it. Your bone is becoming like swiss cheese, it’s turning full of holes due to the active infection.

What tracing the sinus tract shows

Sinus tract tracing is a procedure where your dentist inserts a gutta percha cone directly into the gum boil. They will push it as far as it can go and then take a periapical x-ray of it to see where it ends up.

The x-ray below is what it looks like. Essentially where the gutta percha points to is the tooth with the abscess. This is hard evidence that this condition is a tooth abscess!

x-ray of gutta percha tracing

What that should tell you is that your pimple is not so simple. You need to come to terms with what you’ve just learned because you’ve just been diagnosed with an abscessed tooth. This pimple will need treatment promptly.

Relationship to a dental abscess

We wish to emphasize that your gum boil (parulis) is a type of dental abscess. We’ve provided a diagram below to help you visualize its relationship to other types of dental infections.

Dental Abscesses - Categorization

Essentially it falls under the category of a tooth abscess and is an extension of a periapical abscess. That means it is odontogenic in nature and it originates from the tooth. It does not originate from the gums despite its name.

Who named it anyway?! That’s the source of the confusion if you ask us.


So, is there a difference between a gum boil and an abscess? Nope, there is no difference because they’re essentially one and the same. If you have one, you should contact your dentist immediately because it will need to be treated. It’s presence indicates that you’ve an active infection in your mouth.


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