Wisdom Teeth
An infected wisdom tooth usually causes pain at the back of the jaw, a swollen or red gum, a bad taste or smell, and sometimes swelling of the cheek or difficulty opening your mouth. The most common cause is a partly erupted lower wisdom tooth with a flap of gum that traps food and bacteria (pericoronitis). Rinses and careful cleaning can settle a mild flare-up, but an infection that keeps returning, spreads, or comes with fever needs a dentist or oral surgeon. Trouble swallowing or breathing is an emergency.
Key takeaways
- Typical signs are pain behind the last molar, swollen gum, bad taste, pus, jaw stiffness, and sometimes fever.
- Most infected wisdom teeth are caused by pericoronitis, but decay and abscesses can also infect a wisdom tooth.
- Warm salt-water rinses and gentle cleaning can ease a mild flare-up, but they do not remove the cause.
- Antibiotics may be used for spreading infection or fever, yet the long-term fix is usually removal of the tooth.
- Swelling that spreads toward the eye or neck, trouble swallowing or breathing, or a high fever means going to an emergency department.
What Does An Infected Wisdom Tooth Feel Like?
Wisdom tooth infections often start gradually. You may notice a dull ache at the back of your jaw that becomes sharper when you bite down or swallow. As the infection builds, the gum behind your last tooth can become red, shiny and swollen, and it may bleed easily when you touch it.
Common symptoms include:
- Pain or throbbing at the back of the mouth, sometimes spreading to the ear or jaw
- Swollen, red or tender gum over or beside the tooth
- A bad taste or bad breath that does not go away after brushing
- Pus, or a salty or sour fluid coming from the gum
- Difficulty opening your mouth fully (jaw stiffness)
- Swelling in the cheek or along the jaw
- Swollen, tender glands under the jaw or in the neck
- Fever or feeling generally unwell
You may have only one or two of these. Pain from a wisdom tooth can also come from other causes, such as decay or pressure on the tooth next to it, so an examination and X-ray are the only reliable way to know what is happening.
What Causes A Wisdom Tooth To Become Infected?
Wisdom teeth are the last to come in, usually in the late teens or twenties, and many jaws do not have enough room for them. That makes them prone to a few specific problems.
Pericoronitis (infected gum flap). When a tooth only partly comes through the gum, a flap of tissue can stay over part of the crown. Food and bacteria collect under the flap where a toothbrush cannot reach, and the gum becomes inflamed and infected. This is the most common reason a wisdom tooth gets infected. Our guide to pericoronitis explains it in more detail.
Tooth decay. Wisdom teeth are hard to clean. A cavity can form in the wisdom tooth, or in the molar in front of it, and decay that reaches the nerve can lead to an abscess.
Abscess. A pocket of pus can form at the root or in the gum beside the tooth. Abscesses can cause significant swelling and need prompt treatment.
Impacted teeth. A wisdom tooth stuck under the gum or growing sideways can be harder to keep clean and may be more likely to become infected. You can read more in our guide to impacted wisdom teeth.
Cysts. Rarely, a fluid-filled sac forms around a wisdom tooth that has not come through. A cyst can become infected, and your dentist may see it on an X-ray.
Mild, Moderate Or Urgent?
| Level | What you may notice | What to do |
|---|---|---|
| Mild | Tender gum, bad taste, mild ache, no fever, you can open your mouth normally | Rinse and clean gently, and book a dental or oral surgery appointment soon |
| Moderate | Increasing pain, facial swelling, pus, jaw stiffness, a low fever | See your dentist or call our office promptly; do not wait for it to pass |
| Urgent | Trouble swallowing or breathing, swelling spreading toward the eye, under the jaw or into the neck, a high fever, or you cannot open your mouth | Go to the nearest emergency department |
If you are not sure which group you fall into, call a dentist or oral surgeon the same day and describe your symptoms.
What You Can Do At Home While You Arrange An Appointment
Home care can make a flare-up more comfortable, but it is not a substitute for being seen.
- Rinse with warm salt water. Dissolve about half a teaspoon of salt in a cup of warm water and rinse gently several times a day, especially after meals. Let the water fall out of your mouth rather than spitting forcefully.
- Keep the area clean. Brush gently, including the back of the last tooth, using a soft brush. Food stuck under the gum is a main driver of the problem.
- Use over-the-counter pain relief only as directed on the label and only if it is safe for you. Ask a pharmacist if you take other medications or have a medical condition.
- Chew on the other side and choose soft foods until it settles.
- Do not try to cut, pop or drain the swelling yourself, and do not place aspirin or other tablets on the gum.
If symptoms are getting worse after a day or two, or you develop a fever, do not wait for an appointment: call a dentist or our office.
How Is An Infected Wisdom Tooth Treated?
Treatment depends on the cause and how severe the infection is.
- Examination and imaging. The dentist or surgeon looks at the gum, checks how far you can open, and takes an X-ray. For complex cases, our office can use 3D cone beam (CBCT) imaging to see where the tooth sits in relation to the jaw and nerves.
- Cleaning and irrigation. For pericoronitis, the area under the flap can be cleaned and flushed to remove trapped debris.
- Drainage. If there is an abscess, it may need to be drained.
- Antibiotics when appropriate. Antibiotics can help when an infection is spreading or you have a fever or feel unwell, but they treat the flare-up rather than the cause. They are not routinely needed for a mild flare-up that responds to cleaning.
- Removal of the tooth. If infections keep returning, the tooth is decayed beyond repair, or it is impacted, removal is usually the lasting solution. Removal is often planned once the infection has settled, which can make the surgery more comfortable.
Our guide on antibiotics for wisdom teeth explains when antibiotics are used around wisdom tooth surgery.
Can An Infected Wisdom Tooth Go Away On Its Own?
A mild flare-up can settle for a while with cleaning and rinses, which is why many people put off treatment. But if the tooth is still partly covered by gum or impacted, the trap is still there and the infection often comes back. Repeated infections are one of the most common reasons dentists refer patients to an oral surgeon. An infection that has spread, or an abscess, does not go away safely without treatment.
Can A Wisdom Tooth Infection Spread?
Yes. Infections around a lower wisdom tooth can spread into the cheek, under the jaw, and into the tissues of the neck. This is uncommon, but it can become serious. Warning signs of spread include:
- Swelling that is getting bigger, firmer or spreading
- A fever or chills
- Difficulty or pain when swallowing
- Difficulty breathing
- Being unable to open your mouth
- Swelling around the eye
If you have any of these, go to the nearest emergency department or call 911.
Can I Have An Infected Wisdom Tooth Removed Right Away?
Sometimes. It depends on how severe the infection is, whether you can open your mouth, and the surgeon's assessment. In many cases the first step is to control the infection, then remove the tooth once the swelling has gone down. If you are in pain, tell the office when you call so we can triage your request. Read more about what to expect in our wisdom tooth removal information and pre-surgical instructions, then follow the aftercare instructions you are given.
Care For Infected Wisdom Teeth In Waterloo Region
Our office at 96 Union Street East, near Uptown Waterloo, treats painful and infected wisdom teeth for patients from Waterloo, Kitchener, Cambridge, Guelph and Stratford. Patients with pain or infection are triaged to be seen as soon as possible. Call +1 (519)-743-7811, or ask your dentist to send a referral. Our office is licensed to provide local anesthesia, IV sedation and general anesthesia. For severe swelling, fever, or trouble swallowing or breathing, go to the nearest emergency department.
Sources
- National Institute for Health and Care Excellence. Guidance on the extraction of wisdom teeth (TA1). 2000.
- Scottish Dental Clinical Effectiveness Programme. Drug Prescribing for Dentistry (including management of pericoronitis and dental infections).
- Wisdom teeth and wisdom tooth removal aftercare, Dental Specialty Group Waterloo.
FAQ
How Do I Know If My Wisdom Tooth Is Infected?
Common signs include pain at the back of the jaw, a red and swollen gum, a bad taste or smell, pus, and difficulty opening your mouth. Fever or swelling in the cheek suggests the infection is spreading. A dentist or oral surgeon needs to examine you and usually take an X-ray to confirm the cause.
Is An Infected Wisdom Tooth An Emergency?
It can be. Trouble swallowing or breathing, swelling that spreads toward the eye or neck, a high fever, or being unable to open your mouth means going to the nearest emergency department. A mild infection without these signs should still be seen by a dentist or oral surgeon soon.
Will Antibiotics Cure An Infected Wisdom Tooth?
Antibiotics can calm an infection that is spreading or causing a fever, but they do not remove the cause, such as the gum flap, decay or impacted tooth. That is why infections often return after a course of antibiotics, and why removal of the tooth is commonly recommended for repeated infections.
What Can I Do For The Pain Until My Appointment?
Rinse gently with warm salt water, keep the area clean, chew on the other side, and use over-the-counter pain relief only as directed on the label and if it is safe for you. Do not try to drain or cut the swelling yourself.
Do I Need To Have An Infected Wisdom Tooth Removed?
Not always. A single mild flare-up may settle with cleaning. Removal is usually recommended when infections keep returning, the tooth is decayed or impacted, or there is damage to the tooth next to it. Your dentist or surgeon will explain the options after an examination.
How Long Does A Wisdom Tooth Infection Last?
A mild flare-up may improve within several days with cleaning and rinses, but the length varies. If it is not improving, it is getting worse, or it keeps returning, see a dentist or oral surgeon. Do not wait for symptoms to pass.
This article is general patient education and does not replace an examination, diagnosis, or the written instructions from your own surgeon or dentist. If you have heavy bleeding, trouble breathing or swallowing, or rapidly spreading swelling, call the office or go to the nearest emergency department.