Tooth extraction is a dental procedure in which a tooth is removed from its socket in the jawbone. There are several reasons why a tooth may need to be extracted:

1. Severe Decay or Damage: When a tooth is severely decayed or damaged beyond repair, extraction may be necessary to prevent further infection or pain.

2. Impacted Wisdom Teeth: Wisdom teeth, also known as third molars, can become impacted (unable to fully emerge from the gum line) due to lack of space in the jaw. Impacted wisdom teeth may cause pain, swelling, infection, or damage to neighboring teeth, necessitating extraction.

3. Crowding: In some cases, teeth may need to be extracted to create space for orthodontic treatment, such as braces, especially if there is severe crowding.

4. Gum Disease: Advanced gum disease (periodontitis) can cause the supporting tissues and bone around a tooth to deteriorate, leading to loosening of the tooth. In some cases, extraction may be necessary if the tooth cannot be saved through other treatments.

5. Orthodontic Treatment: Occasionally, teeth may need to be extracted as part of orthodontic treatment to achieve proper alignment of the teeth and jaws.