Which distance is used to express gingival recession in CAL calculations?

• A. CEJ-GM distance
• B. GM-CEJ distance
• C. PD
• D. GM-PD distance

Answer: (B)

The main idea being tested is how gingival recession is quantified for CAL calculations. Gingival recession refers to how far the gingival margin has moved away from the cementoenamel junction, so the recession depth is expressed as the distance from the gingival margin to the CEJ. In calculating clinical attachment level, you combine this recession measure with the probing depth (which measures from the gingival margin down to the base of the pocket). So CAL equals probing depth plus the distance from the gingival margin to the CEJ. Using the distance from the gingival margin to the CEJ specifically captures how much the margin has receded, which is why that metric is used. If you tried to use the CEJ-to-margin distance in the opposite direction, it would complicate interpretation and isn’t the standard way to express recession. The probing depth alone doesn’t describe recession, and other distances don’t reflect the recession component needed for CAL in the same clear, clinically useful way. For example, if the probing depth is 5 mm and recession is 2 mm, CAL would be 7 mm.