Your examination reveals a probing pocket depth of 6 mm on the facial surface of tooth 30. The free gingival margin is 2 mm apical to the CEJ (there is 2-mm recession on the facial). How much attachment loss has there been on the facial of this tooth?

**Core Concept**
The probing pocket depth and recession are key indicators of periodontal health, specifically attachment loss. Attachment loss is the difference between the initial gingival margin and the current free gingival margin, reflecting the extent of periodontal destruction.

**Why the Correct Answer is Right**
To calculate attachment loss, we need to determine the initial gingival margin and the current free gingival margin. The initial gingival margin is typically at the cemento-enamel junction (CEJ). Given a recession of 2 mm on the facial surface, the initial gingival margin is 2 mm coronal to the current free gingival margin. The probing pocket depth is 6 mm. Therefore, the total attachment loss is the sum of the recession and the pocket depth, which equals 8 mm.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not account for the recession when calculating attachment loss.
**Option B:** This option incorrectly calculates the attachment loss by not considering the initial gingival margin at the CEJ.
**Option C:** This option does not provide a valid calculation for attachment loss.

**Clinical Pearl / High-Yield Fact**
When assessing periodontal health, it's essential to consider both probing pocket depth and recession to accurately determine attachment loss.

**Correct Answer:** D. 8 mm

✓ Correct Answer: C. 8 mm