What causes a tooth abscess?

What is an abscess?

Abscesses are pockets of pus formed from the body attempting to wall off and contain an infection, usually caused by bacteria. Pus is made up of white blood cells the body sends to fight the infection, dead bacteria, fluid, and other debris. Abscesses can form in any part of the body. 

Types of abscesses that form in the mouth include:

  • Dental or tooth abscess: Forms by a tooth caused by damage to the tooth surface or gums that allow bacteria to enter the tooth.
  • Periapical abscess: Caused by a problem in the tooth pulp and usually forms at the end of the tooth root. 
  • Periodontal abscess: Caused by a gum infection and usually occurs on the side of the root. 

Abscesses can spread into the surrounding bone, causing pressure and pain in and around the tooth.

What causes a tooth abscess?

Anything that damages the tooth surface or gums may allow bacteria to enter the tooth or its surrounding tissues and start an infection that could result in an abscess. Unless treated early, the infection can spread, and eventually, the body may form an abscess. There are multiple reasons for an infection and a tooth abscess to form, but the most common factors that lead to disease and tooth abscesses include:

  • Tooth decay – Tooth decay is caused by bacteria in your mouth making acid, which slowly destroys the enamel and dentin of your tooth. If decay is not treated early, then a cavity (hole) in your tooth develops, allowing bacteria to enter the tooth pulp, spread down the root, and eventually infect the jawbone.
  • Injuries to the tooth – When a tooth has suffered trauma, it allows the inner pulp to become damaged, which leaves it susceptible to infections. 
  • Broken, cracked, or chipped teeth – Any openings in your tooth can allow bacteria to enter and grow. 
  • Periodontal (gum) disease – When your gums are infected, it allows bacteria to gain access to the deeper tissues that surround your teeth. 
  • Poor dental habits and care – Not taking proper care of your teeth and gums can increase your risk of gum disease, tooth decay, and other dental problems.
  • A diet high in sugar – Frequently eating or drinking foods high in sugar, such as sodas and sweets, is a major factor in developing tooth decay.
  • Dry mouth – A dry mouth can increase your risk of tooth decay and gum disease.

How do I know if I have an abscessed tooth?

Tooth abscesses do not always cause pain and may be diagnosed by an X-ray or dental exam. However, pain will usually be present, ranging from slight to extreme. At times, you may notice swelling or a bad taste in your mouth, depending on the size and location of the abscess. If you are suffering from pain in your mouth or jaw, you should see your dentist to determine the cause. To diagnose the problem, your dentist will typically examine and take X-rays of the area. If an abscess is present, the dentist may be able to see swelling or drainage, and it will usually be seen on the X-ray image. 

Common symptoms of a tooth abscess

If you are experiencing the following symptoms, then you may have a tooth abscess and should see your dentist as soon as possible. Tooth abscess symptoms include:

  • A fever,
  • Bad odor in your mouth,
  • Pain or discomfort while chewing or with hot and cold temperatures,
  • Throbbing in your jaw, ear, or neck, and
  • Tender and swollen lymph nodes

FAQ on tooth abscess causes

A tooth abscess can form when there is tooth decay. It can also form when a tooth is chipped, broken, or injured. When there are openings in the tooth’s enamel, bacteria can enter the tooth and infect the pulp of the tooth. Infection can then spread from the root of the tooth to the bones that support the tooth. An abscess can also form around the tooth from gum disease.

No, a tooth abscess will not go away on its own and requires retreatment. If you do not treat a tooth abscess, then the infection may spread to your jaw and areas of your head and neck.

Tooth abscess signs and symptoms may include throbbing pain in the affected tooth, and this pain can appear suddenly and get gradually worse.


1. Tooth abscess. (2022, June 29) from https://www.mayoclinic.org/diseases-conditions/tooth-abscess/symptoms-causes/syc-20350901 

2. Abscessed tooth. (2023, March 27) from https://my.clevelandclinic.org/health/diseases/10943-abscessed-tooth 

3. Abscessed Tooth Can Cause Serious Illness & Even Death. (2015, June 15) from https://www.southtampasmiles.com/abscessed-tooth 


Additional resources