skip to main content

PD vs CAL Distinction — NDEB AFK MCQ

Instant feedback + full explanation. One question, done properly.

ModeratePeriodontologyPD vs CAL DistinctionNDEB AFK

Which of the following correctly describes the relationship between probing depth and clinical attachment level (CAL)?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — CAL is measured from the CEJ to the base of the sulcus/pocket; probing depth is measured from the gingival margin to the base of the pocket — they differ when gingival recession or hyperplasia is present

Probing depth (PD) is measured from the gingival margin to the base of the sulcus/pocket. Clinical attachment level (CAL) is measured from the CEJ (a fixed anatomical landmark) to the base of the pocket. When the gingival margin is at the CEJ, PD and CAL are identical. With gingival recession, CAL > PD (because the margin has receded apically). With gingival hyperplasia, CAL < PD (because the margin has migrated coronally). CAL is the more reliable measure of periodontal destruction because it uses a fixed reference point.

Reference: Newman – Newman and Carranza's Clinical Periodontology, 13th ed., 2019