Teeth start to pass through the gums (emerge) when the primary (baby) teeth are replaced by the permanent teeth. If a tooth fails to emerge, or emerges only partially, it is considered to be impacted. The most common teeth to become impacted are the wisdom teeth (the third set of molars). They are the last teeth to emerge, usually between the ages of 17 and 21. An impacted tooth remains stuck in gum tissue or bone for various reasons. It may be that the area is just overcrowded and there's no room for the teeth to emerge. For example, the jaw may be too small to fit the wisdom teeth. Teeth may also become twisted, tilted, or displaced as they try to emerge, resulting in impacted teeth. Impacted wisdom teeth are very common. They are often painless and cause no apparent trouble. However, some professionals believe an impacted tooth pushes on the next tooth, which pushes the next tooth, eventually causing a misalignment of the bite.
A Tooth extraction, put simply, is the removal of a tooth from the mouth. Dental extractions are most often performed because a tooth has sustained damage or decay, or cannot be saved by Root Canal treatment, or to prepare for the placement of a Dental Implant. Advanced gum disease may be another contributing factor in a tooth extraction.
Other reasons for a tooth extraction include making space in the mouth for braces or other orthodontic treatment, or in the case of pediatric patients, to allow room for adult teeth to grow.