A 40-year-old African American woman has a jaw lesion described clinically as mixed, but on the periapical radiograph it appears predominantly radiopaque with a thin radiolucent rim. What is the most likely diagnosis?

Correct answer: C. Cemento-osseous dysplasia

• A. Cementoblastoma is a true neoplasm fused to the ROOT of a tooth, forming a radiopaque mass continuous with the root and typically causing pain and expansion. It occurs mostly in young males.
• B. Hypercementosis is excess cementum deposited around a root, widening its outline while the periodontal ligament space remains continuous. It is not a discrete lesion with its own rim.
• C. CORRECT. CEMENTO-OSSEOUS DYSPLASIA has a striking demographic — middle-aged women of African descent — and evolves radiographically through three stages: early radiolucent, then mixed, then mature radiopaque, always retaining a thin radiolucent rim. The teeth involved are VITAL, which is the single most important discriminator. Florid COD involves multiple quadrants; the periapical form clusters around the mandibular anteriors. Management is observation; biopsy and surgery are avoided because the poorly vascularised tissue heals badly.
• D. Condensing osteitis is focal sclerosis at the apex of a NON-VITAL or chronically inflamed tooth. Pulp testing distinguishes it from COD immediately.

Note: Vitality testing is the exam-day discriminator: COD = vital teeth, condensing osteitis = non-vital.