Wisdom Teeth: What They Are, Symptoms, and Whether Yours Need to Come Out

Medically reviewed by Dr. Sam Wood

Wisdom teeth are the third molars, the last four teeth to develop, at the very back of the mouth. They usually erupt between ages 17 and 25, though many people have fewer than four and some have none. Because modern jaws frequently lack room for them, wisdom teeth often become impacted, meaning they are stuck partly or fully beneath the gum or bone, or come in at an angle. Impacted or crowded wisdom teeth cause pain, swelling, infection, decay, and damage to neighboring teeth, which is why removal is so common. Wisdom teeth that erupt fully in good position and can be cleaned do not need to be removed.

What wisdom teeth are

Humans develop three sets of molars on each side, top and bottom. The first come in around age six, the second around twelve, and the third, the wisdom teeth, in the late teens or early twenties, when a person is presumably wiser. Anthropologists think they were useful when human diets were tougher and jaws larger; today they are largely surplus.

Between 5 and 35 percent of people are missing one or more wisdom teeth entirely, depending on the population. A panoramic X-ray in the mid-teens shows how many you have and how they are positioned.

When wisdom teeth come in

The crown forms in the early teens, and the teeth begin to move toward the surface around 17 to 21. Roots finish developing in the early to mid twenties. Eruption can be uneventful, or it can bring weeks of intermittent aching, gum tenderness, and swelling at the back of the jaw as the tooth pushes through. Some wisdom teeth never erupt and stay buried for life.

Symptoms of wisdom teeth problems

• Dull ache or pressure at the back of the jaw
• Swollen, red, or tender gum behind the last molar
• Pain when biting or opening the mouth wide
• Jaw stiffness
• Bad breath or a bad taste, from food trapped around a partly erupted tooth
• Swelling of the cheek or jaw
• Earache or headache on the affected side
• Pain or pressure in the second molar in front
• Fever with swelling, which signals infection

Symptoms often come and go: a few days of soreness, then quiet, then a flare-up weeks or months later.

Impacted wisdom teeth

A tooth is impacted when it cannot erupt into a normal position. Dentists describe impactions by how the tooth is angled and how deep it sits:

Type	Description	Typical problem
Vertical	Upright, but too far back to erupt fully	May erupt partially; food trap
Mesial (angular)	Tilted forward toward the second molar; the most common	Presses on and decays the second molar
Horizontal	Lying sideways in the bone	Damages the second molar root; cysts
Distal	Tilted backward	Often stays buried
Soft-tissue impaction	Through the bone but under the gum	Pericoronitis (gum infection)
Bony impaction	Still partly or fully in the bone	Cysts; harder extraction

Problems wisdom teeth cause

Pericoronitis. A partly erupted wisdom tooth leaves a flap of gum over it. Food and bacteria collect underneath, causing a painful, swollen, sometimes pus-producing infection. It responds to cleaning, rinses, and sometimes antibiotics, but tends to recur until the tooth is removed.

Decay. Wisdom teeth are hard to reach with a toothbrush, and an angled one creates a trap between itself and the second molar. Decay often develops on both teeth, in a spot that cannot be filled well.

Gum disease. The same trapping causes bone loss around the wisdom tooth and the back of the second molar.

Damage to the second molar. An angled wisdom tooth pressing on the second molar’s root can resorb it, sometimes so badly the second molar is lost too.

Cysts and tumors. The sac around a buried tooth can fill with fluid and form a cyst that hollows out the jawbone. Rare, but it is why buried wisdom teeth are monitored with periodic X-rays even without symptoms.

Crowding. The idea that wisdom teeth push the front teeth out of alignment is widely believed but not well supported; lower front teeth crowd with age whether or not wisdom teeth are present. It is not, by itself, a reason for removal.

Do they need to come out?

Not always. Guidance from the American Dental Association and the American Association of Oral and Maxillofacial Surgeons: remove wisdom teeth that cause pain, repeated infection, decay, gum disease, cysts, or damage to adjacent teeth, and consider removing those that are impacted and likely to cause these problems. Keep and monitor wisdom teeth that are fully erupted, functional, cleanable, and healthy.

The reason many dentists lean toward removal in the late teens even without symptoms is timing: roots are shorter, bone is softer, recovery is faster, and the risks of nerve injury and complications are lower than in the thirties and forties. A wisdom tooth that is going to cause trouble is easier to deal with at 19 than at 45. The counter-argument is that some of those teeth would never have caused a problem. It is a judgment call your dentist makes on your X-ray, and it is reasonable to ask why removal is being recommended for a tooth that is not bothering you.

Our wisdom teeth removal guide covers the procedure, cost, and recovery.

Relieving wisdom tooth pain at home

Until you can see a dentist:

• Warm salt-water rinses several times a day, swishing gently toward the back
• Ibuprofen or acetaminophen as directed; ibuprofen also reduces swelling
• A cold compress on the cheek for swelling
• Gently clean the area with a soft brush; a water flosser on low helps flush under a gum flap
• Avoid hard or crunchy foods on that side
• Over-the-counter numbing gel for short-term relief

These manage symptoms; they do not fix the underlying problem.

When to see a dentist

See a dentist if you have pain, swelling, or recurring gum soreness at the back of your jaw, food that consistently packs behind your last molar, or if you are 16 to 25 and have not had a panoramic X-ray to assess your wisdom teeth. See a dentist promptly for swelling of the cheek or jaw, pus, a bad taste that does not clear, difficulty opening your mouth, or a fever with jaw pain; these indicate infection that needs treatment. Swelling that spreads toward the eye or down the neck, or that makes swallowing or breathing difficult, is an emergency; go to an emergency dentist or the ER.

Frequently asked questions

Sources

• American Dental Association (MouthHealthy) – Wisdom teeth
• American Association of Oral and Maxillofacial Surgeons – Wisdom teeth management
• Mayo Clinic – Impacted wisdom teeth
• Cleveland Clinic – Wisdom teeth

This article is for general information only and is not a substitute for professional dental advice, diagnosis, or treatment. Always consult a licensed dentist about your specific situation.