A photograph of the lower arch shows tooth #21 displaced buccally out of the arch. What is the appropriate management?

Correct answer: C. Assess and create the space required, then reposition the tooth into the arch

• A. A finger spring applies force without addressing the underlying space deficiency. It will either fail or produce an unstable result that relapses.
• B. Extracting a healthy premolar (#21 is the mandibular left first premolar) purely because it is displaced discards a sound tooth when repositioning is achievable.
• C. CORRECT. A buccally displaced tooth is displaced because there is INSUFFICIENT SPACE in the arch for it. Moving it lingually without first creating room simply drives it into the adjacent teeth and relapses. The correct sequence is: measure the space discrepancy (arch length analysis), CREATE the required space by expansion, interproximal reduction, distalisation or extraction as the analysis dictates, and only then reposition the tooth.
• D. Premolar extraction may ultimately be part of creating space, but it is a conclusion from the space analysis, not a first-line action taken before assessment.

Note: The orthodontic principle is consistent: SPACE FIRST, then alignment. Analyse the discrepancy before applying any force.