Which statement best describes the radiographic appearance of recurrent caries?

• A. A radiolucent area with diffuse margins beneath or adjacent to a restoration
• B. A radiopaque area within the restoration
• C. A narrow radiolucent line along the root
• D. A circular radiolucent lesion away from the restoration

Answer: (A)

Recurrent caries occur at the margin where a restoration meets tooth structure, usually because the seal between tooth and restoration has degraded and allows decay to propagate under or right beside the restoration. On radiographs, this shows up as a radiolucent area along the tooth-restoration interface, typically just beneath or adjacent to the restoration. The margins of this radiolucent area are often diffuse and irregular because the carious process extends under the restoration and along the restoration margin rather than forming a neat, isolated spot.

This pattern helps distinguish recurrent caries from other findings. Radiolucency within the restoration material itself isn’t the usual sign of recurrent decay, a narrow radiolucent line along the root points more toward root or cervical issues, and a circular radiolucent lesion away from the restoration suggests caries not associated with the restoration margin.