External resorption imaging choice — ORE Part 1 MCQ

Correct answer: D — Small-volume CBCT if justified by treatment planning need

Option D is correct. The stem specifies that the surgical-orthodontic plan depends on exact resorption extent—this is the clinical justification for imaging. Parallax radiographs show only 'possible' resorption; 2D modalities cannot reliably detect or quantify 3D resorption on lingual/buccal surfaces or measure volume loss. Evidence consistently shows CBCT increases resorption detection sensitivity by ~65% compared to conventional radiography and materially alters treatment planning for impacted canines. UK practice applies the principle of justification: imaging is indicated when clinical benefit (here, precise assessment to guide surgical-orthodontic strategy) outweighs radiation risk. Option B causes unnecessary repeated radiation without additional diagnostic information. Option E inappropriately avoids imaging based on radiation alone, ignoring the demonstrated clinical justification. Option C (MRI) does not assess hard tissue resorption. Option A (bitewings) addresses posterior teeth and does not evaluate anterior resorption. The question tests understanding that justified imaging serves evidence-based treatment planning, not that radiation should be avoided when clinically indicated.

Reference: Alqerban A, et al. Root Resorptions on Adjacent Teeth Associated with Impacted Maxillary Canines. Dental Press Journal of Orthodontics. 2022. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8871100/ (supported by diagnostic accuracy literature showing CBCT superiority for resorption detection and by international evidence that CBCT is justified when treatment planning requires precise 3D assessment of hard tissue damage)