Where should the deepest measurement when probing be recorded?

• A. From DB/L line angle to MB/L line angle for buccal and lingual surfaces
• B. From the incisal edge to the root apex
• C. At the middle of the sulcus
• D. At the CEJ level

Answer: (A)

Probing depth is the vertical distance from the gingival margin down to the base of the pocket. To capture the most severe reading on the buccal or lingual aspect, you record the deepest depth along that surface from the distobuccal/lingual line angle to the mesio-buccal/lingual line angle. This ensures the chart reflects the greatest pocket depth on each side of the tooth.

The other options don’t fit because probing depth is not measured from incisal edge to root apex, nor is it recorded at the middle of the sulcus. The reference point is the gingival margin to the base of the pocket, not the CEJ.