Quick answer: Pericoronitis is inflammation—sometimes with infection—of the gum around a partially erupted tooth, most often a lower wisdom tooth. Pain, swollen gum, bad taste, and difficulty chewing are common. A dentist should assess it because cleaning beneath the gum flap is usually the first treatment, while antibiotics are reserved for selected cases with spreading or systemic infection.
What is pericoronitis?
When part of a tooth remains covered by a flap of gum called an operculum, food and plaque can collect in the space underneath. The trapped area is difficult to clean and can become inflamed or infected. This condition is called pericoronitis (sometimes operculitis).
It is most strongly associated with partially erupted mandibular third molars—the lower wisdom teeth—but it can occur around another erupting tooth. Symptoms may be limited to the gum or may become more severe if infection spreads into nearby tissues.
Pericoronitis symptoms
Local symptoms
- pain or tenderness behind the last molar;
- red, swollen gum over or around the tooth;
- pain when chewing or when the opposing tooth bites the swollen flap;
- food trapping, unpleasant taste, or bad breath;
- pus or discharge from beneath the gum flap; or
- pain that may radiate toward the ear, throat, or jaw.
Signs the infection may be spreading
- fever, chills, or feeling generally unwell;
- facial or neck swelling;
- tender enlarged lymph nodes;
- increasing difficulty opening the mouth (trismus); or
- difficulty swallowing.
Emergency warning: difficulty breathing, floor-of-mouth swelling, rapidly increasing facial or neck swelling, inability to swallow saliva, or severe trismus requires urgent emergency assessment. These signs can indicate a spreading deep-space infection.
What causes pericoronitis?
The main problem is a partially erupted tooth with a gum flap that creates a stagnation area. Contributing factors can include:
- limited space for a wisdom tooth to erupt normally;
- food and plaque retained beneath the operculum;
- difficulty reaching the area with a toothbrush;
- trauma when an upper tooth repeatedly bites the swollen lower gum; and
- a tooth position that prevents stable, cleansable eruption.
The condition is not simply evidence that someone “does not brush.” Even people with otherwise good oral hygiene may struggle to clean underneath a deep gum flap.
How dentists diagnose it
A dentist examines the gum, checks for discharge and swelling, measures mouth opening, and assesses whether the opposing tooth is traumatising the area. The clinician also looks for tooth decay, gum disease, an abscess, swollen lymph nodes, and signs that infection has spread.
An X-ray may be appropriate when the wisdom tooth’s position must be assessed, another source of pain is suspected, or surgical treatment is being considered. Routine X-rays are not automatically required for every mild episode.
Pericoronitis treatment
1. Cleaning and irrigation
Local treatment is sufficient in many cases. The dentist can gently flush and debride the pocket beneath the gum flap to remove trapped food, plaque, and discharge. If an abscess is present, drainage may be needed. This directly treats the stagnation area that antibiotics alone cannot clean.
2. Addressing traumatic biting
If the opposing tooth is repeatedly biting the inflamed tissue, the dentist may discuss an occlusal adjustment or, in selected situations, treatment of the opposing tooth. The choice depends on both teeth’s condition and long-term usefulness.
3. Pain relief
A dentist or pharmacist can advise whether paracetamol (acetaminophen), ibuprofen, or another option is safe for you. Follow the label or professional instructions, avoid exceeding the maximum dose, and check first if you are pregnant, take blood thinners, have kidney, liver, stomach, bleeding, or allergy problems, or use other medicines containing the same ingredient.
4. Antibiotics—only when indicated
Antibiotics are not routinely needed for localised pericoronitis. Current prescribing guidance reserves them for features such as fever or malaise, spreading infection, cellulitis, lymph-node involvement, marked trismus, severe local infection, or persistent swelling despite local measures. The drug and duration must be selected by a qualified prescriber using the patient’s allergies, medical history, local guidance, and clinical response.
Do not use leftover antibiotics or someone else’s prescription. Antibiotics cannot remove trapped debris or correct an impacted tooth, and unnecessary use contributes to side effects and antimicrobial resistance.
Safe steps while waiting for dental care
Self-care may temporarily reduce discomfort, but it is not a substitute for assessment when symptoms are significant or persistent.
- Rinse gently with warm salt water and spit it out.
- Carefully clean around the partially erupted tooth with a small, soft toothbrush or single-tufted brush if you can reach it.
- Choose soft foods and chew on the opposite side while the area is painful.
- Avoid smoking, which can impair oral healing and worsen irritation.
- Use an appropriate over-the-counter pain medicine only if it is safe for you.
A clinician may recommend a short course of chlorhexidine mouthwash for some patients, but it is not suitable for everyone and can cause staining or, rarely, allergy. Follow professional or product directions and never swallow it.
Avoid unsafe “home remedies”
Do not place garlic, aspirin, undiluted clove oil, tea-tree oil, or other essential oils directly on the gum. Do not repeatedly use strong hydrogen peroxide solutions. These substances can burn or irritate oral tissue, and apparent pain relief may delay treatment of a spreading infection.
Will the wisdom tooth need removal?
Not every wisdom tooth needs extraction. A tooth that can erupt into a healthy, functional, cleansable position may be monitored after a mild episode settles. Removal is more likely to be considered when pericoronitis is recurrent, a single episode is severe or spreading, the tooth cannot erupt usefully, or there is associated decay, gum disease, abscess, cyst, or damage to the neighbouring tooth.
Definitive surgery is often planned after acute infection is controlled. Depending on the gum and tooth position, options may include removal of the tooth; operculectomy (removing the gum flap) is appropriate only in selected cases because the tissue may regrow if the tooth remains poorly positioned. Read our overview of wisdom-tooth extraction and aftercare.
Can pericoronitis return?
Yes. Symptoms can recur if the same partly erupted tooth and deep gum flap remain. Cleaning the area reduces risk, but anatomy may make reliable home care impossible. Repeated episodes are a reason to discuss definitive management with a dentist or oral surgeon.
Frequently asked questions
Can pericoronitis go away on its own?
A mild episode may temporarily settle, particularly when the area is cleaned, but retained debris and the gum flap can allow it to return. Seek dental advice if pain or swelling persists, recurs, or worsens.
Is pericoronitis contagious?
No. It is a local inflammatory condition related to the tooth and surrounding gum. It is not passed between people.
How long does pericoronitis last?
There is no fixed duration. Improvement depends on severity, drainage and cleaning, the tooth’s position, and whether infection has spread. Lack of improvement or worsening after treatment requires reassessment.
When should I seek urgent dental care?
Arrange urgent dental care for significant pain, pus, increasing swelling, fever, feeling unwell, or reduced mouth opening. Seek emergency help for breathing difficulty, floor-of-mouth or rapidly spreading neck swelling, or inability to swallow saliva.
Key takeaway
Pericoronitis most often affects the gum over a partly erupted lower wisdom tooth. Professional irrigation and local care are first-line for many cases; antibiotics are not automatic. Safe cleaning and warm salt-water rinses can help while awaiting care, but spreading swelling, fever, trismus, swallowing problems, or breathing difficulty require urgent attention.
This article is for general education and cannot diagnose infection or replace personalised advice from a dentist or doctor.
Sources
- Health Service Executive: Pericoronitis antimicrobial guideline
- Royal College of Surgeons of England: mandibular third-molar guidance
- NHS: Wisdom-tooth removal
- NHS England: urgent dental-care guidance