A dental abscess is a collection of pus that develops because of a bacterial infection in or around a tooth or the surrounding gum. It can form in different parts of the mouth, so an abscess does not always look or feel the same from one person to another.

If you have noticed a lump on your gum, swelling around a tooth, or what looks like a small spot containing pus, it is understandable to wonder whether you have an abscess. Understanding where an abscess can develop can make the problem easier to recognise, but a dentist is needed to confirm the cause.

What is Abscess?

An abscess is an enclosed collection of pus that forms when the body’s immune system responds to an infection. Pus contains bacteria, damaged tissue and immune cells that have gathered at the site of infection.

If you’re wondering what is abscess disease, an abscess itself is not a disease but a collection of pus that develops as a result of an infection. When an abscess develops in or around a tooth, it is known as a dental abscess. It indicates that an infection has produced a collection of pus within the tooth or the surrounding tissues.

Dental abscesses can develop around a tooth’s root, within the supporting gum tissues or around a partially erupted tooth. The exact location helps determine what type of infection is present and what needs to be done about it.

Is a Tooth Abscess the Same as a Dental Abscess

In everyday language, tooth abscess and dental abscess are often used to describe the same general problem: an infection that has resulted in a collection of pus in or around a tooth. Strictly speaking, however, not every abscess originates inside the tooth itself. Some develop in the surrounding gum or supporting tissues. This distinction becomes particularly useful when a dentist is determining where the infection started.

What Does a Dental Abscess Look Like?

There is no single appearance that identifies every dental abscess. Depending on its location, you might notice:

  • A swollen area of gum
  • A raised lump beside a tooth
  • A small spot that resembles a pimple
  • Redness around part of the gum
  • Swelling around a partially erupted wisdom tooth
  • Pus or fluid coming from an area of gum

Some abscesses develop deeper within the tissues and may not be visible at all. A visible lump on the gum does not automatically mean you have an abscess either. A dental examination is needed to establish the cause.

Where Can a Dental Abscess Develop?

The position can provide a clue, but location alone cannot confirm that a swelling is an abscess. A dentist may need to examine the area and, where appropriate, take an X-ray to understand what is happening beneath the gum.

  • Abscess Under Tooth: An abscess under tooth may refer to an infection developing around the root of the tooth rather than on the visible crown. A periapical abscess forms at the tip of a tooth root and is commonly associated with infection inside the tooth. The collection may not be immediately visible because the infected area can lie beneath the gum and surrounding bone.
  • Abscess Above Tooth: An abscess above tooth can describe a swelling that appears on the gum higher up than the visible crown, particularly towards the root area. The position of the swelling does not necessarily mean that the infection began in the gum. An infection originating within a tooth can track through the tissues and eventually form a visible swelling on the gum.
  • Abscess Between Teeth: An abscess between teeth may develop within the gum or the tissues supporting the teeth. This can be associated with problems affecting the periodontal tissues rather than the inside of the tooth. Because several dental conditions can produce a swelling between teeth, the area should be examined rather than assuming it is an abscess.
  • Abscess Behind Front Teeth: If you notice a swelling or lump behind your front teeth, its location can make it particularly difficult to identify where it originated. An infection can affect tissues around a tooth without producing an obvious swelling on the front surface.
  • Abscess Under Crown: An abscess under dental crown does not necessarily mean that the crown itself is infected. The tooth underneath the crown can develop problems, including infection of the tissues inside the tooth or around its root. If this happens, the infection may develop beneath the restoration and may not be visible by simply looking at the crown.

What Is a Wisdom Tooth Abscess?

A wisdom tooth abscess is an abscess associated with a third molar, the last adult tooth at the back of the mouth. Wisdom teeth can be difficult to clean when they are partially erupted or impacted. This can allow bacteria to accumulate around the tooth and contribute to infection. However, not every infection affecting a wisdom tooth is an abscess.

  • Abscess Impacted Wisdom Tooth: An abscess impacted wisdom tooth can develop when infection affects a wisdom tooth that cannot erupt normally. An impacted tooth may be blocked by another tooth or simply lack enough space to emerge. When part of the tooth remains covered by gum, bacteria and food debris can collect beneath the gum flap. This can lead to pericoronitis and, in some cases, progress to an abscess.
  • Abscess Behind Wisdom Tooth: An abscess behind wisdom tooth may appear as swelling or tenderness in the gum tissue behind or around the third molar. Because this area can be difficult to access and clean, inflammation and infection can develop around a partially erupted wisdom tooth.
  • Abscess Near Wisdom Tooth: An abscess near wisdom tooth may involve the surrounding gum or a neighbouring tooth rather than the wisdom tooth itself. This distinction matters because pain or swelling at the back of the mouth does not necessarily mean the wisdom tooth is the source. An examination can identify which tooth or tissue is actually affected.

Can a Tooth Abscess Spread to the Sinus?

In some circumstances, an infection associated with an upper tooth can affect or communicate with the nearby maxillary sinus, because the roots of some upper back teeth lie close to the sinus. This can make the relationship between a tooth infection and sinus symptoms complicated. Tooth-related infection is one possible cause of symptoms in this region, but ordinary sinusitis can also cause toothache or pressure around the upper teeth. If you have persistent upper-tooth symptoms alongside sinus problems, a dentist can assess whether the source is dental, sinus-related or both.

What Is the Difference Between an Abscess and Pericoronitis?

These conditions can occur in the same area but are not identical. An abscess is a collection of pus resulting from infection. Pericoronitis is inflammation or infection of the gum tissue surrounding a partially erupted tooth, most commonly a wisdom tooth. It can cause swelling, discomfort, an unpleasant taste and difficulty opening the mouth. Pericoronitis can sometimes progress to an abscess, but the two terms should not be treated as interchangeable.

When Should You Have a Dental Abscess Checked?

If you think you have a dental abscess, you should arrange an urgent dental appointment. A suspected abscess needs professional assessment because the infection can require treatment even if the swelling or discomfort changes. Seek emergency medical help if swelling makes it difficult to breathe, speak or swallow, if there is significant swelling in the mouth, or if you develop swelling or pain around the eye with problems affecting your vision.