An impacted tooth is one that is unable to fully erupt or come out, in its proper location because it is prevented from doing so by tissue, bone, or another tooth. This may occur because the tooth has tilted out of its normal position, or does not have sufficient space to erupt because of surrounding teeth. The teeth that are most commonly impacted are the wisdom teeth, or third molars.
A tooth that is impacted, but does manage to erupt can grow out at an angle as opposed to straight up and out of the gum. A tooth that erupts at an angle, is sometimes referred to as ectopic, which means that it is displaced or incorrectly positioned.
The most frequent problem associated with impacted teeth is infection. As an impacted tooth tries to grown, it can push up the gum, creating a pocket for food debris to collect and decay. The impacted tooth's attempt to grow or emerge can push other surrounding teeth out of their normal position, and can therefore change the alignment and bite of the mouth.
Some people may experience no symptoms of impacted teeth, others may experience irritation or some degree of swelling of the gums around the impacted tooth, pain when chewing or biting, sensitivity to hot and cold, or pain in the areas of the jaw, face and ear.
The dentist or oral surgeon can usually diagnose an impacted tooth with a visual examination. He or she may probe your gums to test their sensitivity, and will also recommend taking x-rays of your mouth to examine how your teeth are positioning under the gums.