Pericoronitis (Infected Gum Around a Wisdom Tooth)

What pericoronitis is

Wisdom teeth (third molars) usually come through between ages 17 and 25. Often there is not enough space in the jaw, so a tooth only partly erupts or remains stuck at an angle (impacted). A flap of gum, called the operculum, stays over part of the biting surface.

The pocket under that flap is hard to clean. Food debris and plaque bacteria collect there, and the gum becomes inflamed. Biting on the swollen flap with the upper wisdom tooth makes it worse. The result is a local infection that can spread into nearby tissues.

Pericoronitis can be:

• Acute: sudden pain and swelling, sometimes with fever and limited mouth opening
• Chronic: milder, low-grade soreness, bad taste and bad breath that comes and goes

Symptoms

• pain at the back of the lower jaw, often spreading to the ear, throat or side of the head
• red, swollen, tender gum over the back tooth
• pain when biting or chewing
• a bad taste or pus in the mouth
• bad breath
• difficulty opening the mouth fully (trismus), because the jaw muscles nearby become inflamed
• pain on swallowing
• swollen lymph nodes under the jaw
• fever and feeling unwell in more severe cases

Causes and risk factors

• a partially erupted or impacted wisdom tooth with a gum flap
• poor cleaning at the back of the mouth
• an opposing upper tooth that bites on the flap
• stress, tiredness, upper respiratory infections and exam periods, which commonly trigger flares
• pregnancy, because of hormonal gum changes

Complications

Most cases stay local, but infection can spread:

• Dental abscess around the tooth
• Facial cellulitis with swelling of the cheek or jaw
• Spread into the spaces of the neck, including peritonsillar or parapharyngeal abscess
• Ludwig angina: a rapidly spreading infection of the floor of the mouth that can block the airway. It is rare but life-threatening.
• Sepsis in rare cases

Repeated episodes can also lead to decay or gum disease on the back of the neighboring second molar.

How it is diagnosed

A dentist diagnoses pericoronitis by examining the gum, checking how wide you can open your mouth, and feeling for swollen glands and facial swelling. A dental X-ray shows the position of the wisdom tooth, whether it is impacted, and whether there is decay or bone loss. A panoramic X-ray or a cone-beam CT scan may be used when removal is being planned.

Treatment

What the dentist will do

• Clean under the flap: gently flush out food debris and bacteria with saline or an antiseptic such as chlorhexidine.
• Drain pus if an abscess has formed.
• Smooth or adjust an upper tooth that is biting on the swollen flap, or remove it if it serves no purpose.
• Prescribe antibiotics, such as metronidazole or amoxicillin, only when there is fever, facial swelling, swollen glands or limited mouth opening. Antibiotics alone, without cleaning, do not solve the problem.

Home care

• Warm salt water rinses: half a teaspoon of salt in a cup of warm water, swished around the back of the mouth several times a day, especially after meals.
• Chlorhexidine mouthwash if your dentist recommends it, for a short course.
• Careful cleaning: a soft or single-tufted toothbrush angled behind the last tooth; an oral irrigator can flush the pocket.
• Pain relief: ibuprofen or acetaminophen (paracetamol) at the label dose. Ibuprofen also reduces swelling, but avoid it if you have stomach ulcers, kidney disease or are in late pregnancy.
• Soft foods and plenty of fluids.

Do not put aspirin directly on the gum, as it burns the tissue.

Preventing recurrence

• Operculectomy: removing the gum flap with a scalpel or laser. The flap often grows back, so this works best when the tooth has room to come through fully.
• Wisdom tooth extraction: the definitive treatment when attacks keep returning or the tooth is impacted and cannot erupt. NICE guidance in the UK recommends removal after a severe episode or two or more episodes of pericoronitis. Removal is usually done once the acute infection has settled.
• Removing the opposing upper wisdom tooth if it bites on the flap.

How long pericoronitis lasts

With professional cleaning and good home care, a mild attack typically settles within 3 to 7 days. Severe episodes treated with antibiotics improve within 2 to 3 days of starting them. Without a long-term fix, pericoronitis returns in many people within months.

Frequently asked questions

How do I know if I have pericoronitis?

Typical signs are pain and swelling of the gum behind or over a partly erupted wisdom tooth, a bad taste, bad breath, pain on biting, and difficulty opening your mouth fully. Pain often spreads to the ear. A dentist can confirm it with an examination and an X-ray.

Can pericoronitis go away on its own?

Mild cases may settle with careful cleaning and salt water rinses, but the infection often comes back because the gum flap remains. See a dentist to have the area cleaned properly and to discuss whether the flap or tooth should be removed. Spreading swelling or fever needs prompt treatment.

What is the best home remedy for pericoronitis?

Warm salt water rinses several times a day, gentle but thorough brushing behind the last tooth, and over-the-counter pain relief help most. Home care does not replace a dental visit, especially if you have fever, facial swelling, swollen glands or difficulty opening your mouth or swallowing.

Do I need antibiotics for pericoronitis?

Not always. Many cases are treated by cleaning under the gum flap and rinsing. Antibiotics are used when the infection is spreading, with fever, swollen glands, facial swelling or limited mouth opening. They do not fix the trapped-food problem, so cleaning is still needed.

Should a wisdom tooth with pericoronitis be removed?

Often, yes. If you have had a severe episode or repeated episodes, or the tooth is impacted and cannot come through fully, extraction is usually recommended. It is generally done after the infection has calmed down. Your dentist or oral surgeon will review the X-rays with you.