The same fractured tooth #8 had endodontic treatment performed. After the root canal, the radiograph shows a truncated (shortened, blunted) root. What is the most likely cause?

Correct answer: C. Root resorption caused by previous orthodontic treatment (orthodontically induced external apical root resorption, OEARR)

• A. Internal root resorption produces a ballooning (enlarged) radiolucency within the root CANAL — the root outline remains intact but the canal enlarges. It does not cause external shortening of the root.
• B. Dilaceration is a developmental sharp angulation or bend in the root, not shortening or blunting of the apex.
• C. CORRECT. Orthodontically induced external apical root resorption (OEARR) is a well-known complication of orthodontic treatment, particularly involving the maxillary central incisors. The root apex becomes shortened (truncated/blunted) due to pressure necrosis of cementum and dentin at the apex during orthodontic force application. CBCT may show this finding, and post-treatment RCT may reveal the shortened root.
• D. External cervical resorption occurs at the CEJ area, producing an external radiolucency at the cervical region — not apical truncation.