ADHP Cariology Practice Test

Recurrent or residual caries on radiographs shows up as a radiolucent (dark) area at the tooth–restoration interface, beneath or adjacent to the restoration, with diffuse, poorly defined margins. This pattern reflects continued demineralization of dentin along and under the restoration margin due to microleakage and remaining decay. Radiopaque signals near a restoration or a radiopaque halo are more consistent with the restorative material itself, not caries, and a radiolucent area in the root region points to root caries rather than a lesion at the restoration margin.