Which luxation injury involves displacement in a NON-AXIAL direction?

Correct answer: C. Lateral luxation

• A. AVULSION is complete displacement out of the socket — total axial displacement, and the most severe injury of the group.
• B. EXTRUSION is partial displacement CORONALLY out of the socket, again along the long axis. It is axial.
• C. CORRECT. LATERAL LUXATION is displacement in a HORIZONTAL direction — facially, palatally or laterally — perpendicular to the long axis of the tooth. It is characteristically accompanied by FRACTURE OF THE ALVEOLAR SOCKET WALL, which is why the tooth is often locked firmly in its new position and gives a high, metallic percussion note despite being displaced.
• D. INTRUSION is displacement APICALLY, directly along the long axis of the tooth into the alveolar bone. It is axial.

Note: Sort the luxations by the direction of movement: AXIAL — intrusion (in), extrusion (out), avulsion (completely out); NON-AXIAL — lateral luxation (sideways), and concussion and subluxation, which involve no displacement at all. Intrusion carries the worst prognosis for the pulp and the highest risk of replacement resorption.