If the gum at the very back of your mouth has become sore, swollen, and tender around a wisdom tooth, you may be dealing with a condition called pericoronitis. It is a common reason for people to call a dentist with wisdom tooth trouble, and it is one that tends to come back if it is ignored.
This guide explains what pericoronitis is, the symptoms to look for, why it happens, what you can do while you wait for an appointment, and how a dentist treats it. It is general education and cannot replace an exam.
What Pericoronitis Is
Pericoronitis is irritation and infection of the gum tissue around a tooth that has only partly come through the gum, most often a lower wisdom tooth. A small flap of gum can stay over part of the tooth, and food and bacteria slip underneath where a toothbrush cannot easily reach. The NHS lists infections in the gums, known as pericoronitis, among the problems that can occur when a wisdom tooth does not have enough room to come through fully, in its patient guidance on removing wisdom teeth.
The American Dental Association makes the same point on its MouthHealthy page about wisdom teeth: wisdom teeth that have partially come through can give bacteria a place to enter the gums and create a place for infection to occur, which may also lead to pain, swelling, and stiffness in the jaw.
Symptoms of Pericoronitis
Symptoms can be mild at first and then flare up. They commonly include:
- Pain or tenderness in the gum at the back of the mouth, sometimes spreading toward the ear or jaw
- Red, swollen gum over or beside a wisdom tooth
- A bad taste or an unpleasant odour from the area
- Difficulty opening your mouth fully, or a stiff jaw
- Pain when you bite down, since the opposing tooth can press on the swollen flap
- In more serious cases, swelling in the cheek or face, a fever, or swollen glands in the neck
Mild flare-ups can settle for a while and then return. That pattern is typical, and it is one reason a dentist wants to look at the tooth instead of leaving it to chance.
Why Pericoronitis Happens
Wisdom teeth usually come through between the ages of 17 and 21, according to the ADA, but they can cause problems at any age, as the NHS points out. Pericoronitis is more likely when:
- The jaw does not have enough room, so the tooth only partly emerges
- The tooth is tilted, which makes the gum flap deeper and harder to clean
- Food gets trapped under the flap and plaque builds up
- The area is irritated by biting on the flap from the tooth above
Our guides on impacted wisdom teeth, why wisdom teeth are sometimes removed, and the signs your wisdom teeth need to be removed explain more about how these teeth cause trouble.
What You Can Do While You Wait for an Appointment
Home care cannot cure an infection, but it can keep the area as clean and comfortable as possible until you are seen:
- Brush carefully with a soft-bristle brush, including as close to the back tooth as you can comfortably reach.
- Rinse gently with warm salt water after meals to help dislodge food.
- Use over-the-counter pain relief as directed on the package if it is safe for you.
- Eat soft foods and avoid chewing on the sore side.
- Do not poke at the gum with toothpicks, pins, or other sharp objects.
These steps keep the area comfortable, but they do not replace an exam.
How a Dentist Treats Pericoronitis
Your dentist will examine the area and usually take an x-ray, as the ADA describes, to see how the wisdom tooth is positioned and whether there is any other problem nearby. Treatment depends on how severe the infection is. It often starts with thoroughly cleaning beneath the gum flap and flushing the area. In some cases your dentist may prescribe an antibiotic, and you will receive instructions for keeping the area clean.
If pericoronitis keeps returning, or if the tooth does not have room to come through properly, your dentist may talk with you about removing the wisdom tooth. The NHS includes infections in the gums among the reasons a wisdom tooth might need to come out. If that becomes the plan, our guides to tooth extraction aftercare and knowing whether a wisdom tooth needs to be removed may be helpful.
Questions to Ask Your Dentist
A few questions can help you make the most of your visit and plan ahead:
- Is the infection limited to the gum flap, or is there another problem with the tooth?
- How should I clean around the tooth until it settles?
- Is this likely to come back, and what would make it less likely?
- Should the wisdom tooth be monitored, or should we talk about removing it?
- Which warning signs mean I should call you before my next appointment?
Wisdom teeth that are not removed should continue to be monitored, the ADA notes, because the potential for problems later on still exists.
When Pericoronitis Is Urgent
Ask for an urgent dental appointment if the pain and swelling are severe or getting worse, or if you have a bad taste, a fever, or feeling unwell. The NHS gives similar advice for problems after wisdom tooth removal. Go to the nearest emergency department or call 911 if you have:
- Swelling that is spreading to your face, jaw, or neck
- Difficulty swallowing or breathing
- Difficulty opening your mouth that is getting worse quickly
You can read about our emergency dental care service for problems that cannot wait.
Frequently Asked Questions
Can pericoronitis go away on its own?
Mild irritation can calm down for a while, especially with careful cleaning. But if a gum flap is still covering part of the tooth, food and bacteria can collect again, and the problem often returns. It is best to have the area examined.
Is pericoronitis contagious?
No. It is caused by bacteria and debris building up under a flap of gum around your own tooth, not by anything you can catch from or pass to another person.
Can adults in their thirties or forties get pericoronitis?
Yes. The NHS notes that wisdom teeth can cause problems at any age. A tooth that has stayed partly covered by gum for years can still become infected.
Does pericoronitis always mean the wisdom tooth has to come out?
No. A first or mild episode can often be managed with professional cleaning and careful home care. Removal is usually discussed when infections keep coming back or the tooth cannot come through properly.
Can I prevent pericoronitis?
You cannot always prevent it, but you can lower the chances. Clean thoroughly around any wisdom tooth that has partly come through, floss where you can reach, and keep up with checkups so your dentist can monitor how your wisdom teeth are developing, as the ADA recommends.
Sore Gum Behind Your Back Tooth?
If the gum around a wisdom tooth is swollen or painful, our team at Pickering Square Dental would be glad to take a look and talk through your options. Learn more about our dental extraction care, or contact us to schedule an appointment.
This article is for educational purposes only and is not a substitute for personalized dental advice, diagnosis, or treatment. Always speak with a regulated dental professional about your specific concerns.
About Dr. Marvin Lean, DDS
Dr. Marvin Lean, DDS, is the owner and lead dentist at Pickering Square Dental. With decades of experience in family and laser dentistry, Dr. Lean provides care focused on clear communication and patient comfort. He is a member of the Ontario Dental Association (ODA) and the Canadian Dental Association (CDA). Dr. Lean and his team provide comprehensive dental care including sedation dentistry, dental implants, emergency dental care, and the Canadian Dental Care Plan (CDCP) to patients in Pickering, Ajax, Whitby, Scarborough, Oshawa, and Markham. Dr. Lean spent the last 20 years as the Dentist for the Toronto Maple Leafs.
