Teeth are impacted when they fail to emerge through the gums, or emerge only partially, at the expected time.
Your wisdom teeth, also called third molars, usually begin to erupt between the ages of 17 and 21. Because they are the last to emerge in the mouth, wisdom teeth are the most common teeth to become impacted. This may happen because a wisdom tooth is turned to the side, tilted or otherwise positioned incorrectly in the jaw. Wisdom teeth also become impacted when there is not enough space in the jaw or the mouth for them to emerge.
An impacted tooth can be painless, and you may not even realize it’s there. However, when an impacted wisdom tooth tries to erupt, the overlying gum may swell and cause pain, which may also be felt in nearby teeth or the ear on that side. A partially erupted tooth can collect food and other debris, which can lead to gum swelling and an infection .If untreated, this infection can spread toward the throat or into the neck. Impacted teeth also can cause problems if they develop decay or if they push on the neighboring molar, which could lead to tooth movement or decay, as well as changes in the bite (the way the teeth come together). Impacted teeth also can cause cysts and other benign (harmless) jaw tumors. These can lead to bone destruction. However, this is rare.
There is no way to prevent an impacted tooth, but careful dental hygiene — brushing, flossing or the use of water-jet devices — can reduce the risk of infection.
You can sometimes relieve minor irritation by rinsing with warm salt water (1/2 teaspoon of salt in a cup of water) or by taking over-the-counter painkillers.
If the tooth continues to cause pain, is infected or is interfering with nearby teeth, the usual treatment is for the tooth to be extracted.