Oral Surgery · single question
A panoramic radiograph shows an impacted third molar causing resorption of the distal root of the adjacent second molar. What type of resorption is this?
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Correct answer: C. External resorption
Pressure from an impacted tooth against an adjacent root causes external resorption — the root surface is resorbed from the outside.
- A. Replacement resorption (ankylosis) is when root structure is replaced by bone, typically following avulsion.
- B. Internal resorption occurs within the pulp canal and expands outward — it appears as a balloon-like expansion of the canal space.
- C. CORRECT. External resorption occurs on the external root surface. Pressure from an impacted third molar against the distal root of the second molar causes external inflammatory or pressure resorption.
- D. Cervical root resorption begins at the cervical area and is associated with trauma, ortho treatment, or bleaching — not impaction pressure.