Wisdom Teeth
An impacted wisdom tooth is a third molar that cannot come fully into its normal position because it is blocked by bone, gum, or the tooth in front of it. It may be completely hidden in the jaw or only partly through the gum. Impaction is described by the tooth's angle (for example mesial, horizontal, vertical, or distal) and depth (soft tissue, partial bony, or full bony). Many impacted wisdom teeth cause no symptoms, but they can lead to infection, decay, gum problems, or cysts, which is why they are evaluated with X-rays and often removed by an oral and maxillofacial surgeon.
Key takeaways
- Impaction is very common because most jaws do not have room for four extra molars.
- Mesially angled (tilted forward) impactions are among the most common, especially in the lower jaw.
- Symptoms, when present, include pain, swollen gum behind the last molar, bad taste, and jaw stiffness.
- A panoramic X-ray shows the position; a 3D CBCT scan may be added when roots are near the nerve or sinus.
- Removal is usually straightforward in experienced hands, with local anesthetic, IV sedation, or general anesthesia available.
What Does &Quot;Impacted&Quot; Mean?
Teeth erupt along a path through the bone and gum until they meet the opposing teeth. Wisdom teeth are the last to develop, usually appearing in the late teens or early twenties. By then, the space at the back of the jaw is often limited. When a wisdom tooth runs out of room, is angled the wrong way, or is blocked by the molar in front, it becomes impacted: stuck partway or completely below the surface.
Impaction is not a disease in itself. It describes position. What matters clinically is whether the tooth is causing, or is likely to cause, problems.
Types Of Impacted Wisdom Teeth By Angle
| Type | Description | What it often means |
|---|---|---|
| Mesioangular (mesial) | Tilted forward toward the molar in front | Among the most common, especially in the lower jaw; can trap food and cause decay on the adjacent molar |
| Vertical | Upright but not fully erupted | May erupt further with time, or remain partly covered by gum |
| Horizontal | Lying on its side, crown facing the molar in front | Cannot erupt; often presses on the adjacent tooth; usually needs surgical removal |
| Distoangular | Tilted backward, away from the other molars | More common in the upper jaw; removal can be more complex in the lower jaw |
| Buccal or lingual | Tilted toward the cheek or tongue | Less common; position affects the surgical approach |
Types By Depth
| Depth | Description |
|---|---|
| Soft tissue impaction | The crown is through the bone but still covered partly or fully by gum |
| Partial bony impaction | Part of the crown is still within the jawbone |
| Full bony impaction | The tooth is completely encased in bone |
Depth, angle, root shape, and the tooth's relationship to the nerve and sinus together determine how complex removal will be, how long surgery takes, and what recovery to expect. They also affect the fee; see wisdom teeth removal cost in Ontario.
Symptoms Of An Impacted Wisdom Tooth
Many impacted wisdom teeth are painless and are found on routine dental X-rays. When symptoms occur, they commonly include:
- Pain or tenderness at the back of the jaw, sometimes spreading to the ear
- Red, swollen gum behind the last molar
- A bad taste or bad breath that does not go away
- Food getting stuck behind the back teeth
- Difficulty opening the mouth fully
- Swollen glands under the jaw
- Pain when biting on the back teeth
Swelling of the gum over a partly erupted tooth is called pericoronitis. It often comes and goes, and repeated episodes are a common reason for removal. Read more in pericoronitis: infected wisdom tooth gum.
Symptoms that need urgent care
Go to the emergency department or seek urgent care if you have swelling spreading into the cheek, jaw, or neck, fever, or any difficulty swallowing or breathing.
Problems Impacted Wisdom Teeth Can Cause
| Problem | How it happens |
|---|---|
| Pericoronitis | Food and bacteria trapped under the gum flap cause inflammation and infection |
| Decay | Hard-to-clean wisdom teeth, or the molar in front, develop cavities |
| Gum disease and bone loss | Pockets form behind the second molar |
| Damage to the adjacent molar | A tilted wisdom tooth presses on the root of the tooth in front |
| Cysts | A fluid-filled sac can form around an impacted tooth and damage bone |
| Crowding concerns | Often cited by patients; the relationship to front-teeth crowding is debated |
Not every impacted wisdom tooth will cause these problems. Your surgeon weighs the tooth's position, your age, your symptoms, and your oral health when recommending removal or monitoring. For the evidence behind these decisions, see when should wisdom teeth be removed.
How Impacted Wisdom Teeth Are Diagnosed
Panoramic X-ray
A panoramic X-ray shows all four wisdom teeth, their angle and depth, root development, and the approximate relationship to the lower jaw nerve and the maxillary sinus. For most patients, this is all that is needed.
When a 3D CBCT scan is added
If the panoramic X-ray suggests that a lower wisdom tooth root is close to or overlapping the inferior alveolar nerve canal, a cone beam CT scan shows the exact relationship in three dimensions. That helps the surgeon explain the risk of numbness accurately and plan the safest approach. Our Waterloo office has an in-office CBCT scanner. Learn more in dental CBCT scan explained.
How Is An Impacted Wisdom Tooth Removed?
- Anesthesia. The area is numbed with local anesthetic. Many patients choose IV sedation or general anesthesia for comfort. See IV sedation vs general anesthesia.
- Access. For teeth under the gum or bone, a small incision in the gum exposes the tooth, and a small amount of bone may be removed.
- Sectioning. Deeply impacted or horizontal teeth are often divided into smaller pieces, which allows removal with less bone removal and less pressure on surrounding structures.
- Cleaning. The socket is cleaned of debris.
- Closure. The gum is usually closed with stitches, often dissolving ones.
- Recovery instructions. Our nursing staff reviews home care before you leave with your escort.
Wisdom tooth removal is the most common procedure performed at our office. All outpatient surgery is performed under appropriate anesthesia to maximize comfort.
Risks Of Removing An Impacted Wisdom Tooth
Your surgeon reviews risks based on your own imaging before surgery. The main ones include:
| Risk | What to know |
|---|---|
| Swelling, bruising, and jaw stiffness | Expected; peaks around day 2 to 3 and then improves |
| Dry socket | Loss of the clot a few days after surgery; more common with lower wisdom teeth and in smokers |
| Infection | Uncommon; watch for worsening swelling after day 3, fever, or pus |
| Nerve irritation causing numbness of the lip, chin, or tongue | Usually temporary when it occurs; permanent numbness is rare. Risk is assessed from your imaging |
| Sinus involvement (upper teeth) | Occasionally a small opening into the sinus occurs and is managed with specific instructions |
| Damage to adjacent teeth or fillings | Rare |
Early removal, when roots are not yet fully formed, is often associated with a more straightforward procedure and recovery.
Recovery After Impacted Wisdom Tooth Removal
Most patients feel mostly better within 3 to 7 days. Swelling becomes noticeable the day after surgery and peaks around day 2 to 3. Key steps include biting on gauze to control bleeding, ice on the cheeks for the first 24 hours only, no rinsing or spitting on the first day, no straws or smoking, soft foods, and taking medication as directed. Restrict physical activity for at least four days.
Detailed guides:
Impacted Wisdom Teeth In Teens Vs Adults
Age changes both the decision and the experience of removal:
| Teens and young adults | Adults over about 30 | |
|---|---|---|
| Root development | Roots often still forming, and farther from the nerve | Roots fully formed and sometimes curved or close to the nerve |
| Bone | Softer and more flexible | Denser, so removal can take longer |
| Typical recovery | Often faster, with less swelling | Can take a few days longer |
| Decision | Removal often recommended for teeth unlikely to erupt properly | Healthy, stable, fully covered teeth may be monitored; problematic teeth are removed |
This is why dentists and orthodontists commonly recommend an evaluation in the mid-to-late teens. If an impacted tooth is going to cause trouble, dealing with it earlier usually means a simpler procedure and recovery. For adults, removal is still very common and safe; the surgeon simply plans for the added complexity.
Can An Impacted Wisdom Tooth Be Left Alone?
Sometimes. A wisdom tooth that is fully covered by bone, shows no disease, is not affecting neighbouring teeth, and is in a stable position may be monitored with periodic X-rays, particularly in older adults where the surgical risk is higher. A tooth that is partly erupted and cannot be cleaned, is causing infection or decay, or is damaging the molar in front is usually better removed. This decision is individual and is made with your surgeon.
For retained wisdom teeth, "clinical assessment at regular intervals to prevent undesirable outcomes is advisable." — Ghaeminia et al., Cochrane Database of Systematic Reviews, 2020
Impacted Wisdom Tooth Removal In Waterloo, Kitchener, And Cambridge
Our office at 96 Union Street East, near Uptown Waterloo, treats impacted wisdom teeth for teens and adults from Waterloo, Kitchener, Cambridge, Guelph, Stratford, and surrounding communities. Most patients are referred by their dentist or orthodontist. Dr. Kevin J. McCann has provided oral and maxillofacial surgery and anesthesia care in Kitchener-Waterloo since 1994, and our surgical team offers local anesthetic, IV sedation, and general anesthesia. Imaging, including 3D CBCT when needed, can be taken in the office.
To book an assessment, call +1 (519)-743-7811 or ask your dentist to send a referral. Learn more on our wisdom teeth page.
Sources
- Ghaeminia H, Nienhuijs MEL, Toedtling V, et al. Surgical removal versus retention for the management of asymptomatic disease-free impacted wisdom teeth. Cochrane Database of Systematic Reviews, 2020.
- National Institute for Health and Care Excellence. Guidance on the extraction of wisdom teeth (TA1). 2000.
- Wisdom teeth and wisdom tooth removal aftercare, Dr. Kevin J. McCann Oral & Maxillofacial Surgery.
FAQ
What Is An Impacted Wisdom Tooth?
It is a wisdom tooth that cannot erupt fully into its normal position because it is blocked by bone, gum, or the tooth in front of it. It may be completely hidden or partly through the gum.
How Do I Know If My Wisdom Tooth Is Impacted?
A dental X-ray is the only reliable way to know. Signs can include pain or swelling at the back of the jaw, a bad taste, food trapping, or a gum flap over a partly visible tooth, but many impacted teeth cause no symptoms.
Does An Impacted Wisdom Tooth Always Need To Be Removed?
No. Teeth that are causing problems or are likely to cause them are usually removed. Healthy, stable impacted teeth without disease may be monitored with regular X-rays.
Is Removing An Impacted Wisdom Tooth Painful?
The surgery itself is done with local anesthetic, and sedation or general anesthesia is available, so you should not feel pain during the procedure. Soreness and swelling afterward are managed with a pain plan and improve over several days.
What Is A Horizontal Impacted Wisdom Tooth?
It is a wisdom tooth lying on its side, with the crown facing the molar in front. It cannot erupt on its own and often presses on the adjacent tooth, so it is usually removed surgically, often in sections.
How Long Does It Take To Recover From Impacted Wisdom Tooth Removal?
Most people feel mostly better within 3 to 7 days. The gum closes over a few weeks, and the bone heals over several months.
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.