Radiology · patient case question
What most likely happened to the posterior molar?
Patient case: 84-year-old with a heavily restored dentition
Patient: 84-year-old man, first visit in several years.
Chief complaint: Wants his mouth checked over.
History: Medically stable, independent, no bisphosphonates, no radiotherapy. Good manual dexterity.
Findings: Radiographs show amalgam restorations in nearly all posterior teeth. On one posterior molar roughly half the coronal tooth appears absent with a clean cavity outline. A premolar looks clinically like a retained root, but radiographically the root is intact, the canal is patent, and bone support is good. A third tooth has an established periapical infection.
Show answer and explanation
Correct answer: A. The restoration was lost
- A. CORRECT. A clean, sharply outlined cavity where an amalgam used to sit, with the surrounding tooth structure intact, is a LOST restoration. The preparation outline is still recognizable because it was cut, not dissolved.
- B. Recurrent caries produces an ill-defined, irregular radiolucency undermining the remaining structure, not a clean preparation outline.
- C. Internal resorption is a radiolucent expansion centred on the pulp space, continuous with the canal.
- D. A congenital malformation would have been present lifelong, not a new change in a restored tooth.