Radiology · patient case with 3 questions
Radiopaque Lesions
demo: 22-year-old female
chief: Routine radiographic survey.
history: Non-contributory. Asymptomatic.
meds: None
findings: Finding A: a well-defined radiopacity in the region of the missing #16, also visible on 3D reconstruction. Finding B: a cluster of small tooth-like radiopacities surrounded by a thin radiolucent halo, located between the mandibular premolars, blocking eruption.
Question 1
The dense, well-circumscribed radiopacity in the #16 region on both the film and the 3D reconstruction is most consistent with:
Show answer and explanation
Correct answer: A. Osteoma
- A. Correct. An osteoma is a benign proliferation of mature compact or cancellous bone, appearing as a homogeneous, well-circumscribed radiopacity. Its presence on the 3D reconstruction confirms it is a real anatomic structure, not an artifact.
- B. Condensing osteitis is a localized sclerotic reaction at the apex of a tooth with long-standing low-grade pulpal inflammation — it requires a tooth.
- C. A compound odontoma consists of multiple small tooth-like denticles with a surrounding radiolucent rim, not a homogeneous mass.
- D. An artifact would not reproduce on an independent 3D reconstruction.
Note: Multiple osteomas should prompt a search for Gardner syndrome: supernumerary teeth, epidermoid cysts, and colonic polyps with near-certain malignant transformation.
Question 2
The cluster of small tooth-like radiopacities with a thin radiolucent halo between the mandibular premolars represents:
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Correct answer: D. Compound odontoma
- A. A cementoblastoma is a radiopaque mass fused to and continuous with a root, with a radiolucent rim.
- B. A complex odontoma is a disorganized amorphous mass of dental tissue with no tooth-like forms, and it favors the posterior mandible.
- C. A single supernumerary would show one discrete tooth with a normal follicle, not a cluster of denticles.
- D. Correct. A compound odontoma is a collection of multiple small, recognizable tooth-like denticles surrounded by a thin radiolucent capsule — most often anterior and a common cause of failed eruption.
Question 3
Which lesion appears radiographically as a radiopaque mass attached directly to the root of a vital tooth, with a surrounding radiolucent halo?
Show answer and explanation
Correct answer: B. Cementoblastoma
- A. Osteoid osteoma is a small nidus lesion of long bones, rare in the jaws.
- B. Correct. A cementoblastoma is fused to the root, obscures its outline, has a radiolucent rim, and is characteristically painful — unusual for a benign lesion. The tooth remains vital.
- C. Ossifying fibroma is a well-demarcated intrabony lesion of mixed density that displaces rather than fuses to roots.
- D. Hypercementosis is a bulbous thickening of the root with an intact PDL space and lamina dura following the enlarged contour — no separate radiolucent halo.