A well-circumscribed, dense radiopaque mass is noted in the posterior maxilla (#16 region). Which benign tumor of mature bone fits best?

Correct answer: A. Osteoma

• A. Correct. An osteoma is a benign tumor of mature compact/cancellous bone appearing as a dense, well-defined radiopacity (and can present in the jaws/sinus region).
• B. Incorrect. A compound odontoma is composed of multiple small tooth-like denticles, not homogeneous bone.
• C. Incorrect. An artifact has no true anatomic correlate; a discrete, reproducible mass argues against it.
• D. Incorrect. Cemento-osseous dysplasia is typically a mixed lesion around tooth apices, classically the mandibular anterior.

Note: Among the listed options the keyed answer is osteoma; the radiographic differential for a midface radiopacity also includes compound odontoma and artifact.