There may be acute pain when a tooth is infected or the nerve in the tooth is dying, due to abscess, periodontal disease, a fractured tooth or trauma to the mouth. A procedure called root canal treatment can often prevent the tooth being pulled out. The infection is treated from within the tooth by the injured nerve and pulp tissue being taken out. Then the roots are sterilised and sealed to prevent bacteria re-entering, thus alleviating the pain. Following root canal treatment the tooth may be restored with bonded material or with a crown.