What radiographic finding is most characteristic of external root resorption?

What radiographic finding is most characteristic of external root resorption?

• A. Symmetrical enlargement of pulp chamber
• B. Widened periodontal ligament space
• C. Irregular or discontinuous root outline with loss of root structure adjacent to the periodontal ligament
• D. Increased radiodensity at root surface

Answer: (C)

External root resorption appears on radiographs as an irregular, discontinuous loss of the root outline along the external surface adjacent to the periodontal ligament. The root border becomes ragged or scooped as dentin is resorbed, often with a localized radiolucent defect right next to the PDL. The surrounding PDL space may look widened due to inflammatory changes, but the hallmark feature is the irregular, disrupted external contour of the root. In contrast, internal resorption shows a symmetrical enlargement of the pulp chamber and canal, not an irregular external defect. Increased radiodensity at the root surface would indicate sclerosis, not resorption.

External root resorption appears on radiographs as an irregular, discontinuous loss of the root outline along the external surface adjacent to the periodontal ligament. The root border becomes ragged or scooped as dentin is resorbed, often with a localized radiolucent defect right next to the PDL. The surrounding PDL space may look widened due to inflammatory changes, but the hallmark feature is the irregular, disrupted external contour of the root. In contrast, internal resorption shows a symmetrical enlargement of the pulp chamber and canal, not an irregular external defect. Increased radiodensity at the root surface would indicate sclerosis, not resorption.