Dental abscess

What is a dental abscess?

A dental abscess (or phlegm on in more colloquial language) is an accumulation of pus caused by a bacterial infection originating inside the tooth (tooth pulp). It usually occurs as a result of an untreated caries or a tear or crack in the tooth that allows bacteria to access it.

The treatment consists of draining the abscess and eliminating the infection of the affected area. The tooth can be saved with an endodontic treatment but in some cases it may be necessary to remove the affected tooth. If the dental abscess is not treated properly, serious health complications can occur.

You can prevent dental abscess with good oral hygiene habits, a good diet and going regularly to check-ups with the dentist.

Symptoms of a dental abscess

The most frequent symptoms of a dental abscess are:

  • Severe, persistent and throbbing pain
  • Sensitivity to heat
  • Pressure sensitivity when chewing or biting
  • Fever
  • Inflammation of the face or cheek
  • Swollen or tender lymph nodes under the jaw or in the neck
  • Sudden discharge of malodorous liquid with bad taste and disappearance of pain if the abscess breaks.

When to go to the dentist

Visit your dentist as soon as possible if you have any signs or symptoms of a tooth abscess. If you have a fever and swelling of the face and cannot contact your dentist, go to the Emergency Department. Fever and inflammation may indicate that the infection has spread to the maxilla and adjacent tissues and even to other areas of your body.

Causes of a dental abscess Dental abscess

The dental abscess occurs when the bacteria invade the dental pulp, which is the innermost and softest part of the tooth formed by connective tissue and which contains blood vessels and nerve endings.

Bacteria enter through a cavity or fissure in the tooth and extend to the root. This infection causes inflammation and the space so narrow in which this inflammation occurs force the pus to leave forming a bag (or abscess) at the tip of the root.


The dental abscess will not be cured without treatment. If the abscess breaks, the pain may decrease significantly but dental treatment is still necessary. If it does not drain, the infection can spread to the maxilla and other areas of the face and neck. In extreme cases it can cause septicemia (widespread infection throughout the body with risk of death).

If you have a weakened immune system and leave the abscess untreated you have much more risk of the infection spreading.

Tests and diagnosis

In addition to examining the affected tooth and the area around it, your dentist can perform one or more of the following tests:

  • Gently tap the affected tooth. A tooth with an abscess in the root is very sensitive to touch and pressure.
  • X-rays to identify the abscess and extent of infection
  • Lab tests. In those cases in which the first antibiotics are not working, knowing which bacteria is the cause of the infection allows a much more specific treatment.

Treatment and medication

The main objective of the treatment is to drain the abscess and eliminate the infection. For this, the dentist will usually opt for one of these procedures:

  • Perform an endodontic. This treatment helps eliminate the infection and save the tooth. For this the dentist drills the tooth, eliminates the infected pulp and drains the abscess. The pulp chamber and root canal of the tooth are filled with a special material and sealed. Then the dentist protects the tooth with a crown. An endodonced tooth can last a lifetime if properly cared for.
  • Extract the affected tooth. If the tooth cannot be saved, the dentist will remove it and drain the abscess to eliminate all infection.
  • Prescription of antibiotics. It may not be necessary if the infection is limited to the abscess area. In cases where the infection is more widespread (nearby teeth, jaw, face, neck, etc.) your dentist will prescribe antibiotics to stop the infection. If you have a depressed immune system for some reason, you may also recommend antibiotics.

Home care

  • While the abscess area heals, you can do the following to relieve the discomfort:
  • Rinse your mouth with warm salt water
  • Take some painkiller

How to prevent abscess

Avoiding tooth decay is essential to prevent a phlegm on from coming out. Therefore all the tips to prevent cavities are applicable here:

  • Brush your teeth at least twice a day with a fluoride toothpaste
  • Use dental floss or interproximal brushes daily
  • Use dental floss or interproximal brush provided that food is packaged between the teeth
  • Avoid the most harmful foods for the teeth
  • Visit the dentist regularly for professional cleaning and revisions
  • Use the mouthwash that your dentist has recommended for you