What is the approximate distance from the cemento-enamel junction to the alveolar crest on a typical radiograph?

• A. Approximately 3 mm
• B. Approximately 1 mm
• C. Approximately 0.5 mm
• D. Approximately 2 mm

Answer: (B)

Distance from the cemento-enamel junction to the alveolar crest on a radiograph reflects the bone level around the tooth. In a healthy periodontium, the alveolar crest sits just below the CEJ, and on a standard radiograph this distance is about 1 mm. That small gap indicates normal bone height relative to the tooth and preserves the biologic width. If the distance increases, it signals bone loss and periodontal disease progression. While measurements can vary with image angle and magnification, 1 mm is the typical approximate value seen on a normal radiograph.