External Cervical Resorption — ORE Part 1 MCQ
Instant feedback + full explanation. One question, done properly.
Educational content. Not a substitute for clinical judgement or local policy.
Reveal the answer and explanation
Correct answer: B — Cone beam CT (CBCT)
Explanation lettering: C = shown as A · A = shown as B · E = shown as C · B = shown as E
The correct answer is A: Cone beam CT (CBCT). External cervical resorption requires three-dimensional imaging to fully characterise the lesion. While the periapical radiograph detected the lesion, it shows only the coronal-apical extent and cannot assess circumferential spread or depth. Multiple prospective and comparative studies confirm CBCT is significantly superior to 2D radiography for ECR diagnosis and classification. CBCT achieves perfect diagnostic accuracy (ROC Az = 1.000 vs 0.830 for periapical imaging) and allows determination of lesion location, size, depth, circumferential involvement, and pulp status—all critical for treatment planning (conservative repair vs endodontic treatment vs extraction). Additional periapical radiographs (B) remain 2D and cannot overcome this limitation. Lateral cephalometric (C) and panoramic (D) radiographs are 2D overview modalities insufficient for detailed local assessment. Transillumination (E) is a clinical examination technique and cannot quantify resorption extent. For a vital, asymptomatic tooth with detected ECR, CBCT is the standard diagnostic step to guide definitive management.
Reference: Vaz de Souza D, et al. External Cervical Resorption: A Comparison of the Diagnostic Efficacy Using 2 Different Cone-beam Computed Tomographic Units and Periapical Radiographs. J Endod. 2017;43(3):336–342. https://pubmed.ncbi.nlm.nih.gov/27939734/