What does the radiographic appearance of a furcation involvement look like?

• A. Conical tooth on xray
• B. Widened lamina dura around the root
• C. Radiolucent lesion at the crown
• D. Cortical bone thickening at the tooth neck

Answer: (A)

Furcation involvement means bone loss in the area where the roots diverge. On a radiograph, the telltale sign is loss of interradicular bone and a change in the tooth’s silhouette in that region. As bone around the furcation diminishes, the remaining tooth structure and surrounding bone can project in a way that looks cone-shaped on the image, giving a cone-like or conical appearance of the tooth on x-ray. This descriptive cue is why the option mentioning a conical tooth on x-ray best matches furcation involvement. The other options describe radiographic features that don’t correspond to furcation changes, such as a radiolucent area at the crown or generalized changes to the lamina dura or cortical bone that aren’t specific to the furcation.