The largest healthy acceptable space between the tooth surface and the gingival margin (gingival crevice) is?

• A. 3mm
• B. 1mm
• C. 5mm
• D. 2mm

Answer: (A)

The space between the tooth surface and the gingival margin is the gingival sulcus. In a healthy mouth, this depth is shallow, typically 1 to 3 millimeters. The largest acceptable depth is 3 millimeters because depths greater than this indicate pocket formation and possible periodontal attachment loss. A sulcus depth of 3 mm is still compatible with healthy gingival tissue, while deeper measurements suggest inflammation or disease and require further evaluation.

When assessing, a periodontal probe is gently inserted into the sulcus to the deepest point, and readings are used alongside other signs (like bleeding on probing) to determine periodontal health. So, 3 mm represents the upper limit of a healthy sulcus, with deeper depths signaling potential problems.