Which radiographic projection best evaluates SEVERE bone loss around posterior teeth?

Correct answer: D. Vertical bitewing

• A. The horizontal bitewing is the standard for interproximal caries and for MILD to moderate bone loss, but the crest falls off the image once loss is severe.
• B. A panoramic film gives a useful overview but has magnification, distortion and superimposition that make it unreliable for measuring crestal levels.
• C. Occlusal films image the arch in cross-section and give no information about crestal bone height.
• D. CORRECT. Once bone loss is advanced, the horizontal bitewing's field is too shallow — the crest has receded below the lower edge of the film. Turning the receptor VERTICALLY captures more apico-coronal height, so the crest, the furcations and the root lengths all appear on a single image with minimal distortion.

Note: The measurement rule: bone loss is assessed from the CEJ to the crest, and 1 to 2 mm is normal. Radiographs consistently UNDERestimate loss because they show only the interproximal bone — buccal and lingual defects are invisible. Probing remains the standard.