Pediatric Dentistry · single question
A 5-year-old girl lost tooth E (primary maxillary right second molar) one month ago. She now presents with a bluish bump on tooth F (primary maxillary right first molar) that appeared 3 days ago, and tooth F appears darker than the other teeth. What does she most likely have?
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Correct answer: B. Sinus tract (parulis)
Tooth darkening combined with a bump on the gingiva (parulis/sinus tract) indicates pulp necrosis with periapical pathology. A sinus tract (parulis) is a draining tract from a periapical abscess to the oral mucosa. The tooth discoloration (darker than others) indicates internal hemorrhage from pulp necrosis. An eruption cyst would be over an erupting tooth, not a primary molar in situ.
- A. Incorrect. An eruption cyst forms over an erupting tooth's crown — it would be relevant if a permanent tooth was erupting beneath, but the clinical picture with tooth darkening points to a necrotic primary tooth with a draining sinus.
- B. CORRECT. Tooth darkening (pulp necrosis/internal hemorrhage) + gingival bump = sinus tract (parulis) draining a periapical abscess from necrotic tooth F.
- C. Incorrect. A mucocele is a mucous extravasation cyst from a minor salivary gland — it is not associated with tooth pathology or discoloration.
- D. Incorrect. A peripheral giant cell granuloma is a reactive gingival lesion (reddish-purple) — not directly caused by pulp necrosis/darkening.
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