Wisdom teeth: signs of trouble

Reviewed by Dr. Samar Fadavi, DDS

Short answer: Wisdom teeth are the third molars that usually appear between the late teens and mid-twenties. Many come in without trouble. They need attention when they are trapped (impacted), partly through the gum, decayed, or pushing on the tooth in front. Swelling, pain at the back of the mouth, a bad taste or trouble opening are signs to book an exam with X-rays.

Do your wisdom teeth need to come out?

Wisdom teeth have a reputation for causing trouble, and many people assume they must always be removed. That is not the case. Some people never develop them, some have them come in straight and healthy, and some keep them for life with no problems. Others have teeth that are trapped in the jaw, come through only partly, or sit at an angle that makes them hard to clean. Those are the situations where wisdom teeth cause pain, infection and damage to neighbouring teeth.

This guide explains how wisdom teeth develop, the signs of trouble, how dentists decide whether removal is needed, what you can do at home in the meantime, and what to expect if they do need to come out. It is general information for patients in Scarborough and East Toronto, not advice for your own mouth.

What wisdom teeth are

Most adults have 32 permanent teeth, including four wisdom teeth: one at the back of each side, top and bottom. They are the last teeth to form and usually start to come through between about 17 and 25. Because they arrive last, there is sometimes not enough room for them at the back of the jaw.

A wisdom tooth can be:

• Fully erupted: it has come all the way through and lines up with the other teeth.
• Partially erupted: part of the tooth shows through the gum, with a flap of gum still covering the rest.
• Impacted: it is trapped in the gum or bone and cannot come through, often because it is tilted toward the tooth in front, toward the back, or sideways.
• Missing: some people never develop one or more wisdom teeth.

Signs your wisdom teeth may be causing trouble

• Pain or tenderness at the very back of the mouth, behind the last molar.
• Red, swollen or tender gum over a partly erupted tooth.
• A bad taste or bad breath that keeps returning from the back of the mouth.
• Food catching behind the last molar.
• Swelling of the cheek or jaw on one side.
• Difficulty opening your mouth fully, or pain when swallowing.
• Pain in the tooth in front of the wisdom tooth, especially with cold or sweet foods.
• Earache or headache on one side without another clear cause.

Some impacted wisdom teeth cause no symptoms at all, and problems are found only on an X-ray. That is one reason routine check-ups in the late teens and twenties include a look at how the wisdom teeth are developing.

The most common problems

Pericoronitis (infected gum flap)

When a wisdom tooth is only partly through, a flap of gum often covers part of it. Food and bacteria collect under the flap, which is very hard to clean. The gum can become inflamed and infected, causing pain, swelling, a bad taste and sometimes difficulty opening the mouth. Mild episodes often settle with careful cleaning and warm salt water rinses, but they tend to return. Repeated episodes are one of the most common reasons for removing a lower wisdom tooth.

Decay

Wisdom teeth are hard to reach with a toothbrush and floss, so they decay easily. Decay can also start on the back of the second molar, the tooth in front, where a tilted wisdom tooth traps food against it. That second molar is an important chewing tooth, so protecting it is often the main reason to act.

Gum and bone problems

A wisdom tooth leaning against the second molar can create a deep pocket between the two teeth, leading to gum disease and bone loss at the back of the second molar.

Cysts

Occasionally a fluid-filled sac (cyst) forms around an impacted wisdom tooth and slowly enlarges, which can damage bone and neighbouring teeth. This is uncommon and usually found on an X-ray.

Crowding

Many people worry that wisdom teeth push the front teeth out of line. Research suggests wisdom teeth are not usually the main cause of crowding, which happens with age for several reasons. Crowding alone is rarely a reason to remove wisdom teeth.

How the decision is made

There is no single rule that wisdom teeth must stay or go. At an exam, the dentist looks at:

• Whether the tooth has room to come through and be cleaned.
• Its angle and its relationship to the second molar.
• Any decay, gum infection or bone loss already present.
• For lower teeth, how close the roots sit to the nerve that gives feeling to the lip and chin. 3D CBCT imaging can show this in more detail when needed.
• Your age, general health and medications. Healing is usually quicker and simpler in younger adults.
• Your symptoms and how often they return.

Healthy, fully erupted wisdom teeth that you can clean well can often stay. Impacted teeth with no symptoms and no signs of disease may simply be monitored with X-rays over time. Teeth that cause repeated infection, decay or damage to neighbouring teeth are usually recommended for removal. You will be shown the X-rays and told the reasons for any recommendation, as well as the option of waiting.

What you can do at home

1. Brush the back teeth carefully. Open slightly less wide, which gives the brush more room behind the last molar. A small-headed or single-tuft brush helps.
2. Clean between the last two molars. Floss or a small interdental brush removes food that catches there.
3. Rinse with warm salt water. Half a teaspoon of salt in a cup of warm water, swished gently after meals, helps keep a sore gum flap clean.
4. Use pain relief as directed. Over-the-counter pain relievers can help while you arrange an appointment. Follow the package directions and check with a pharmacist if you take other medications.
5. Book an exam. Even if pain settles, repeated episodes are a sign that the tooth needs to be assessed.

What to avoid

• Putting aspirin or a pain tablet on the gum. It can burn the tissue.
• Ignoring swelling. Swelling of the face or jaw, fever or trouble swallowing are reasons to be seen the same day.
• Squeezing or poking the gum flap. This can push bacteria deeper.
• Using old antibiotics from home. Antibiotics only help in some situations, and the wrong one can cause harm. They do not remove the cause.
• Delaying because the pain went away. Pericoronitis often returns, sometimes at an inconvenient time such as exams, travel or pregnancy.

If wisdom teeth need to come out

Removing a wisdom tooth is one of the most common procedures in dentistry. The area is numbed thoroughly with local anaesthetic. A fully erupted tooth may be removed much like any other tooth. An impacted tooth may need a small opening in the gum, and sometimes the tooth is divided into sections so it can be removed with less force. Some cases are referred to an oral surgeon, for example when the roots are very close to the nerve or sedation is preferred.

Recovery usually involves some swelling and discomfort for a few days, peaking around day two or three. Following aftercare instructions closely, including not smoking or using straws, helps prevent a painful complication called dry socket. Our tooth extraction page explains how extractions and aftercare are handled at our office. If you feel nervous, our page on care for nervous patients explains how we pace visits.

Wisdom teeth at different stages of life

Teens

In the early to mid-teens, wisdom teeth are still forming inside the jaw. A panoramic X-ray taken around this time shows whether all four are developing, how much room there is and which way they are angled. Nothing usually needs to be done yet, but it gives a useful starting point and helps when orthodontic treatment is being planned.

Late teens and twenties

This is when most wisdom teeth try to come through and when symptoms usually begin. If removal is likely to be needed, this is often a good time, as roots are not yet fully formed and healing tends to be quicker. Students and young workers often plan removal around exams, holidays or a lighter work week.

Thirties and beyond

Wisdom teeth that have caused no trouble by the thirties often stay that way, but they still need checking. Gum disease and decay can develop on them or on the tooth in front, and teeth that were silent for years can start to cause problems. Removal in older adults is still common and safe, though healing may take a little longer and more planning around health and medications may be needed.

Pregnancy

Hormone changes can make a gum flap over a partly erupted wisdom tooth more likely to flare up. If you are planning a pregnancy and have had repeated episodes, it is worth having the tooth assessed beforehand. If a flare-up happens during pregnancy, call us; there are safe ways to manage it.

Getting ready for a removal

If removal is recommended, a little planning makes recovery easier. Stock up on soft foods such as yogurt, soup, eggs, mashed potatoes and smoothies eaten with a spoon. Arrange a ride home if sedation is planned. Plan a quiet day or two afterwards, and avoid heavy exercise for a few days. Have cold packs ready for the first day and pain relief your pharmacist has confirmed is suitable for you. Tell us about every medication you take, especially blood thinners and medications for bone health.

When to see a dentist

• You have pain, swelling or a bad taste at the back of the mouth.
• Food keeps catching behind your last molar.
• You are in your late teens or twenties and have never had your wisdom teeth checked on an X-ray.
• You are planning orthodontic treatment, a pregnancy or extended travel and want to know whether your wisdom teeth are likely to cause trouble.

Call the same day if you have facial swelling, fever, difficulty opening your mouth or difficulty swallowing. Our same-day emergency care page explains how to reach us. If swelling affects your breathing, call 911 or go to the nearest emergency department.

Questions about wisdom teeth

Do all wisdom teeth need to be removed?

No. Healthy wisdom teeth that are fully through, in line with the other teeth and easy to clean can often stay. Removal is recommended when they cause or are likely to cause problems.

Is it better to remove wisdom teeth young?

When removal is needed, it is usually simpler in younger adults, because the roots are not fully formed and healing is quicker. That does not mean every young person needs them removed.

Can wisdom teeth cause headaches or earaches?

Pain from a lower wisdom tooth can spread to the ear, jaw and side of the head. Other causes are possible, so an exam helps find the source.

What is an impacted wisdom tooth?

It is a wisdom tooth that is trapped in the gum or bone and cannot come through fully, usually because there is not enough room or it is tilted.

How long does recovery take?

Most people feel much better within three to five days, with the gum healing over a few weeks. Recovery varies with the difficulty of the removal and your health.

Will my face swell?

Some swelling is common after removing an impacted tooth. Cold packs on the cheek during the first day help. Swelling that increases after day three, or comes with fever, should be checked.

Can a wisdom tooth come in later in life?

Occasionally a wisdom tooth begins to come through in an older adult, often when other teeth have been lost or bone changes. It should be checked on an X-ray.

Related guides

• Wisdom tooth recovery, day by day
• Dry socket: how to prevent it
• Dental x-rays: types and safety