Why is the gum sore around my wisdom tooth? Pericoronitis!

A girl holding her cheek and looking concerned

Read time: 4 mins

What is Pericoronitis?

Pericoronitis is a common dental problem of the gums in young adults (17-24yrs) when the wisdom teeth normally erupt (break through the gum) into the mouth. It’s a painful inflammation caused by the infection of the soft gingival tissues (gums) over or around a partially erupted wisdom tooth. Pericoronitis is one of the common reasons we need to extract wisdom teeth.

What causes Pericoronitis?

Pericoronitis is almost always associated with tooth impaction, and especially with impacted wisdom teeth.

Generally pericoronitis infection will be caused by:

  • Gum flap infection: when there is a partially erupted wisdom tooth, part of the tooth is exposed, and part of it remains covered by a flap of gum tissue. Food particles and other debris may get trapped under this flap of gums and cause an initial inflammation. The decomposition of food particles, in combination with poor oral hygiene that allows the accumulation of dental plaque and tartar, promotes the growth of bacteria and the development of an infection. Even if the patient has good oral hygiene, it’s not easy to clean under the flap with a toothbrush, so inflammation and infection can easily develop.
  • Trauma: several incidents of pericoronitis are caused by a minor trauma of the gums around a tooth. Gum flaps over a partially impacted tooth are usually already inflamed. The same occurs around and over a wisdom tooth that is still completely under the gums because the tooth puts tension on the gums that cover it. The inflamed issue is more susceptible to minor injuries during chewing either from food components or the opposing teeth. If the lower gum flap is already inflamed and swollen, the upper tooth may bite down on it, causing additional irritation and swelling, and causing the development of pericoronitis.

Other factors which are considered that predispose to pericoronitis are emotional stress, fatigue, upper respiratory tract infections, second trimester of pregnancy and menstruation.

Pericoronitis may affect any tooth that has eruption problems and becomes impacted, but since impaction is a very rare condition in the rest of the teeth, it most often occurs with the wisdom teeth, most commonly those of the lower jaw. Pericoronitis is a main cause of wisdom tooth pain.

What are the symptoms of Pericoronitis?

Symptoms of pericoronitis can include:

  • Pain
  • Swollen gum tissue in the area of the affected tooth. It can be difficult to bite down comfortably without catching the swollen tissue between your teeth. It can progress to become a knob-like mass of tissue that is very painful when you chew or open and close your mouth
  • Bad breath (caused by the trapped food and bacteria under the gum flap)
  • Jaw stiffness
  • Discharge of pus from the gum near the tooth
  • A bad smell or taste in the mouth (caused by pus leaking from the gums)

More serious symptoms include:

  • Severe throbbing pain
  • Swollen lymph nodes under the chin in the neck
  • Muscle spasms in the jaw
  • Swelling on the affected side of the face
  • Difficulty opening the mouth
  • Fever
  • Dysphagia – difficult in swallowing food

How is Pericoronitis Diagnosed?

Pericoronitis is easy to diagnose during a clinical examination. In most cases the swelling of the gum tissues around an impacted tooth is a clear and very obvious sign of pericoronitis. The gums are red, swollen or draining fluid or pus.

If pericoronitis is caused by a partially erupted or impacted tooth then we will usually take an x-ray to determine the exact position, size, alignment, and orientation of the tooth and decide about the treatment accordingly.

The dentist will also look for other symptoms that may indicate that the swelling and infection has spread beyond the jaw to the cheeks and neck. In severe cases of pericoronitis the infection may spread into surrounding tissues, developing to cellulitis, a very serious, often life-threatening infection that must be treated quickly to prevent further and possible swelling of the airway.

 Pericoronitis treatment

Depending on the etiology, symptoms, and severity of pericoronitis we may recommend a combination of the following treatments:

  • Improvement of oral hygiene to keep the area clean
  • Frequent rinsing with warm salt water to sooth the patient. External application of heat should be avoided since it promotes spread of infection towards the facial skin
  • Soft diet to avoid further irritation of the gum issue
  • Analgesics (painkillers)
  • Removal of the flap of gum covering the tooth (if we decide not to extract the tooth immediately)
  • Drainage, if an abscess has developed
  • Extraction of the impacted tooth (to eliminate the causative factor of pericoronitis).
  • The most severe cases when the swelling and infection has spread to the neck may need to be treated in a hospital with intravenous antibiotics

The only permanent solution for treatment of the pericoronitis is the extraction of the impacted wisdom tooth.

Prevention of pericoronitis

The only thing a patient with an impacted wisdom tooth can do to prevent pericoronitis is to take extra care for the oral hygiene around that tooth, and try to avoid injuring the area with hard foods.  Unfortunately there is not much that can be done to prevent the impaction of a tooth.


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