A dental extraction (also referred to as tooth extraction, exodontia, exodontics, or informally, tooth pulling) is the removal of teeth from the dental alveolus (socket) in the alveolar bone. Extractions are performed for a wide variety of reasons, but most commonly to remove teeth which have become unrestorable through tooth decay, periodontal disease, or dental trauma, especially when they are associated with toothache. Sometimes impacted wisdom teeth (wisdom teeth that are stuck and unable to grow normally into the mouth) cause recurrent infections of the gum (pericoronitis), and may be removed when other conservative treatments have failed (cleaning, antibiotics and operculectomy). In orthodontics if the teeth are crowded, sound teeth may be extracted (often bicuspids) to create space so the rest of the teeth can be straightened. The decision to extract teeth for orthodontic reasons should only be made by an orthodontist, so the correct decision is made.