What is Wisdom teeth, impacted?

Wisdom teeth, impacted

What are impacted wisdom teeth?

Your wisdom teeth are the last adult teeth to appear. There are four of them right at the back of your mouth. But sometimes they don't come through the gum properly. This usually happens when there isn't enough space, or when the teeth are growing in the wrong direction. When this happens, they're called impacted wisdom teeth.

You may wonder if you need to have your impacted wisdom teeth taken out. But as long as they aren't causing you pain or damaging other teeth, you may not need to have them removed. Having them taken out can be painful. And, like any surgery, the operation has risks.

Key points for people with impacted wisdom teeth

Wisdom teeth are normal adult teeth.
If they don't come through the gums properly, they're said to be impacted.
Unless your wisdom teeth are causing you trouble, you probably do not need to have them taken out.
But if they are causing pain, are damaging other teeth or your jawbone, or keep causing infections, you need to have them removed.

Your wisdom teeth

The four wisdom teeth usually come through your gums when you are in your late teens and 20s. Sometimes they come through a lot later. They got their name because they come through later than your other teeth, when you're "older and wiser."

Wisdom teeth are the third set of molars.
Molars are the big teeth toward the back of your mouth that you use for chewing food.
You get your first set of molars at the age of 6 or 7 and the second set between 11 and 13. Before your late teens, you'll normally have two molars on both sides of your upper and lower jaw.
But not everyone has wisdom teeth. In some people, they never appear.

When your wisdom teeth get impacted

Sometimes wisdom teeth don't come through the gums properly. This usually happens because there's not enough room for them or because they're pointing in the wrong direction. Your gums, jaw and other teeth get in the way. For some people, all four wisdom teeth become impacted.

Wisdom teeth are the third set of molars to come through your gums.

They may be completely impacted (they are hidden below the gum). Or, they may be partially impacted (part of the tooth appears above the gum).

Source:
Song F, O'Meara S, Wilson P, et al.
The effectiveness and cost-effectiveness of prophylactic removal of wisdom teeth.
Health Technology Assessment. 2000; 4: 1-55.

¹
Wisdom teeth are more likely to get impacted than other teeth because they emerge later than other teeth, when there is less room.

If you have small jaws, you may be at higher risk of impacted wisdom teeth.

Problems caused by impacted wisdom teeth

Most people don't get any trouble from their impacted wisdom teeth. But some people do get problems. Impacted wisdom teeth that cause problems are usually in the lower jaw rather than the upper jaw.

Here are the most common problems:

Infection

The gum around your impacted wisdom teeth can become infected. This is the main problem caused by impacted wisdom teeth.

Source:
Silvestri AR Jr, Singh I.
The unresolved problem of the third molar: would people be better off without it.
Journal of American Dental Association. 2003; 134: 450-455.

² One study found that 1 in 10 people with impacted wisdom teeth got an infection.

Source:
Silvestri AR Jr, Singh I.
The unresolved problem of the third molar: would people be better off without it.
Journal of American Dental Association. 2003; 134: 450-455.

² You are more likely to get an infection if your wisdom teeth have partly appeared above the gum (they are partially impacted).

You may have a flap of gum where the wisdom tooth has partly come through.
Bits of food,

bacteria
Bacteria are tiny organisms. There are lots of different types. Some are harmful and can cause disease. But some bacteria live in your body without causing any harm.

bacteria and saliva can collect under this flap. You may find it difficult to keep clean.
This can cause an

infection
You get an infection when viruses, bacteria, fungi or other tiny organisms get into your body. These bugs are so tiny that you can't see them without a microscope. For example, an infection in your airways causes the common cold. And an infection in your skin can cause rashes such as athlete's foot.

infection. You will get redness and pain.
You may also get bad breath and swelling in your mouth. You may find it hard to open your mouth properly.
The infection can spread to your cheek, neck or jawbone.
You may get an abscess. This is when infected pus collects in the gum. You may need to have it drained.

Source:
Song F, O'Meara S, Wilson P, et al.
The effectiveness and cost-effectiveness of prophylactic removal of wisdom teeth.
Health Technology Assessment. 2000; 4: 1-55.

¹
If an infection is bad, you may need treatment with

antibiotics
These medications are used to help your immune system fight infection. There are a number of different types of antibiotics that work in different ways to get rid of bacteria, parasites and other infectious agents. Antibiotics do not work against viruses.

antibiotics.
After it has cleared up, it's possible that an infection will come back.

Decay

It can be hard to keep your impacted wisdom teeth clean.
This can lead to tooth decay and cavities (holes in the tooth).
If it's too hard to fill the cavity in a wisdom tooth, or if you keep getting cavities, your dentist may recommend that you have the wisdom tooth removed.

Damage to other teeth

Wisdom teeth may make it difficult for you to keep nearby teeth clean. You may then get cavities in these teeth. But this doesn't happen often.

Source:
Song F, O'Meara S, Wilson P, et al.
The effectiveness and cost-effectiveness of prophylactic removal of wisdom teeth.
Health Technology Assessment. 2000; 4: 1-55.

¹
Wisdom teeth that are trying to come through can also push neighboring teeth out of position. This can damage the roots of these teeth. But this is rare.

Source:
Song F, O'Meara S, Wilson P, et al.
The effectiveness and cost-effectiveness of prophylactic removal of wisdom teeth.
Health Technology Assessment. 2000; 4: 1-55.

¹
Because they're hard to clean, wisdom teeth can cause gum disease that spreads to the teeth around them.

Cysts

If your wisdom teeth are impacted, you may get a cyst (a sac filled with fluid) in your jaw. But this is rare.
The cyst can damage your jawbone or nearby teeth.
It is very rare, but cancer can develop from the cyst.

Source:
Song F, O'Meara S, Wilson P, et al.
The effectiveness and cost-effectiveness of prophylactic removal of wisdom teeth.
Health Technology Assessment. 2000; 4: 1-55.

¹

Teeth overcrowding

Wisdom teeth may press on other teeth.
Some dentists worry that this could make your front teeth look crooked and change your "bite."
However, researchers say that any crowding caused by wisdom teeth should be slight, and it shouldn't affect the appearance of your teeth or your bite.

Source:
Guralnick G, Laskin D.
NIH Consensus Development Conference for removal of third molars.
Journal of Oral Surgery. 1980; 35: 235-236.

³

Source:
Harradine NW, Pearson MH, Toth B.
The effect of extraction of third molars on late lower incisor crowding: a randomized controlled trial.
British Journal of Orthodontics. 1998; 25: 117-122.

⁴

How does my dentist know I have impacted wisdom teeth?

Your dentist will normally be able to see if your wisdom teeth are impacted and causing trouble by examining your mouth. He or she will look at the areas where your wisdom teeth are supposed to come through and check whether:

Your dentist may take an X-ray to see if your wisdom teeth are impacted.

The area is swollen or whether a tooth has partly come through your gum
The tooth is pressing on the one next to it
You have signs of infection, such as redness or swelling
You have other problems such as tooth decay and cavities.

Your dentist will probably take an

X-ray
X-rays are pictures taken of the inside of your body. They are done by passing very small amounts of radiation through your body and onto film. X-rays can also be used as a treatment, such as in radiation therapy for cancer.

X-ray of the area to get a better look.

If your teeth are impacted but not causing you problems, your dentist may want to keep an eye on them. He or she may take X-rays of the impacted teeth every time you come in for a checkup. It's important you visit your dentist for regular checkups.

Sources for the information on this page:

Song F, O'Meara S, Wilson P, et al.The effectiveness and cost-effectiveness of prophylactic removal of wisdom teeth.Health Technology Assessment. 2000; 4: 1-55.

Silvestri AR Jr, Singh I.The unresolved problem of the third molar: would people be better off without it.Journal of American Dental Association. 2003; 134: 450-455.

Guralnick G, Laskin D.NIH Consensus Development Conference for removal of third molars.Journal of Oral Surgery. 1980; 35: 235-236.

Harradine NW, Pearson MH, Toth B.The effect of extraction of third molars on late lower incisor crowding: a randomized controlled trial.British Journal of Orthodontics. 1998; 25: 117-122.

This information was last updated on Mar 06, 2009

This information is for educational use only, and is not a substitute for prompt professional medical advice. Readers should always consult a physician or other professional for advice and treatment.
© BMJ Publishing Group Limited 2009. All rights reserved.

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