On a dental image, a region that appears dark indicates radiolucency.

• A. Radiolucency
• B. Radiopacity
• C. Opacity
• D. Luminosity

Answer: (A)

Dark regions on a dental radiograph indicate radiolucency because these areas are less dense and let more X-rays pass through, so they appear darker on the film or sensor. In contrast, denser structures absorb more X-rays and show up as radiopaque, which means lighter or whiter on the image. Radiolucency is the standard term for these dark areas; radiopacity describes the light areas, while opacity and luminosity aren’t used in dental radiography terminology.