An extraction is the process of removing a tooth or piece of root from the oral cavity. The most common type of extraction is the removal of the wisdom teeth. Most people have their wisdom teeth extracted when they are teenagers or young adults. These teeth often erupt horizontally, creating pressure and pain on the teeth in front of them, which can eventually lead to an infection and/or crooked teeth.
Another reason a person may have teeth extracted is as a precursor to orthodontic treatment. Dentists may recommend certain teeth be removed as part of their overall plan to create more room in the mouth to straighten the other teeth.
In most other cases, primarily among adults, teeth must be extracted due to decay or a trauma to the jaw. When a tooth has an extensive amounts of decay or has a fracture line that reach down to the root, the tooth is no longer salvageable and must be taken out to keep an infection from developing and spreading into the jaw.