After a direct blow to the mouth, the patient, usually a child 7 to 9 years old, may have a permanent tooth that has been completely knocked out of its socket (avulsion) (Fig. 43.1). The tooth is intact down to its root, from which hangs the delicate periodontal ligament that used to be attached to alveolar bone. Alternatively, the tooth may have only become loosened within its normal anatomic position (subluxation) or partially displaced laterally, partially extruded from the socket, or intruded into the alveolar ridge (luxation) (Fig. 43.2). These disfiguring, hemorrhagic injuries are often dramatic and a frightening experience for the patient, the parents, and other bystanders.