Although extractions can be done for many different reasons, they are most frequently done to remove teeth that are irreparable due to oral trauma, periodontal disease, or decay, particularly when the extraction is accompanied by toothache. When other conservative measures (such as cleaning, antibiotics, and an operation) have failed, impacted wisdom teeth—wisdom teeth that are trapped and unable to grow normally into the mouth—may be extracted. They can also occasionally result in recurring gum infections (pericoronitis). In orthodontics, healthy teeth (usually bicuspids) may be excised if the teeth are crowded in order to make room for the remaining teeth to straighten.