Which term describes a dense area that appears white on a radiograph?

• A. Radiopacity
• B. Radiolucency
• C. Artifact
• D. Contrast

Answer: (A)

Dense structures that appear white on a radiograph are described as radiopacity. This happens because they absorb more X-ray photons, blocking the beam and leaving a bright, opaque area on the film or sensor. Enamel, dentin, bone, and metallic restorations are all radiopaque for this reason.

Radiolucency is the opposite concept, describing areas that are darker because they allow more X-rays to pass through. An artifact refers to a distortion or feature not related to the actual anatomy, often caused by technical issues or processing. Contrast is about the difference in density between adjacent structures, typically enhanced with a contrast agent to improve visibility, but it’s not the inherent property of a single dense structure appearing white. Therefore, the dense white region is radiopacity.