Pathology · patient case with 1 question
Primary dentition with an abnormal mandibular tooth count
Scenario: Photographs and multiple radiographs. The patient has a full PRIMARY dentition with 10 teeth in the MAXILLA and 9 teeth in the LOWER arch.
Question 1
What is wrong with the mandibular teeth?
Show answer and explanation
Correct answer: A. Fusion
- A. Correct — and the TOOTH COUNT is what decides it. Fusion is the union of two separate tooth germs, so the total count is REDUCED (9 instead of 10 in the lower arch). This matches the case exactly.
- B. A mesiodens is a supernumerary tooth in the maxillary midline and would INCREASE the count, not reduce it.
- C. Gemination is the incomplete splitting of a SINGLE tooth germ. Counting the anomalous structure as one tooth gives a NORMAL count — this is the standard way of separating the two, and it does not fit a count of 9.
- D. Hypodontia is the developmental ABSENCE of a tooth. The count would also be reduced, but a radiograph showing a single wide, notched crown with joined dentin identifies fusion rather than a simple missing tooth.
Note: ⚠️ SOURCE NOTE. The recall highlighted 'gemination' but the recaller's own annotation states the answer is FUSION 'por el conteo de menos' (because of the reduced count) — and the reduced count is decisive. Memory aid: FUSION = FEWER.