GM-CEJ distance measurement is defined as what?

• A. The distance between the CEJ and root apex
• B. The distance from mucogingival junction to CEJ
• C. The distance between the gingival margin and the cementoenamel junction
• D. The distance from contact point to CEJ

Answer: (C)

The measurement uses the gingival margin as the soft-tissue border and the cementoenamel junction as the fixed bony landmark to quantify how far the gingiva extends or recedes along the tooth. In this context, the distance from the gingival margin to the CEJ tells you how much gingival recession there is (a larger distance means more recession when the margin is apical to the CEJ; if the margin is coronal to the CEJ, the distance decreases). This is why the correct description is the distance between the gingival margin and the cementoenamel junction. The other options describe different landmarks: CEJ to root apex is a root length, mucogingival junction to CEJ is a different reference point, and the distance from a contact point to the CEJ does not involve the gingival margin.