How is MGI determined during examination?

• A. By probing vertically at the marginal gingiva
• B. By running a probe horizontally from the vestibule toward the gingival margin with light pressure
• C. By palpating externally
• D. By taking radiographs

Answer: (B)

The main idea is that this index assesses gingival inflammation by evaluating the gingival margin with a gentle, surface-level probe stroke. You determine the Modified Gingival Index by moving the probe horizontally from the vestibule toward the gingival margin with light pressure. This horizontal, non-deep approach focuses on the soft-tissue appearance at the margin—color, contour, consistency, and whether bleeding occurs—so you can gauge inflammatory change without entering the sulcus or measuring pocket depth.

Why this is the best method here: gingival inflammation is reflected in surface tissue changes at the margin, not in how deep the pocket is, which is what vertical probing or radiographs would reveal. External palpation doesn’t assess the gingival tissue in the same way, and radiographs show bone/crest relationships rather than the inflammatory state of the gingiva itself. The horizontal probing method minimizes tissue trauma while directly assessing the marginal gingiva for signs of inflammation, which is exactly what the Modified Gingival Index aims to quantify.