Probing Depth
Also written as: PD
The measured distance in millimetres from the gingival margin to the base of the sulcus or periodontal pocket, recorded during a periodontal assessment.
Full Definition
Probing depth (PD) is determined by inserting a calibrated periodontal probe into the gingival sulcus or pocket and measuring the distance from the free gingival margin to the probe tip at the base of the pocket. It is a primary clinical parameter used alongside clinical attachment level to assess periodontal disease severity. Values exceeding 3 mm in healthy tissue are generally considered indicative of a pathological pocket. Editors must distinguish probing depth from clinical attachment level, which is measured from the cementoenamel junction. Recording conventions vary slightly by institution, so editors should confirm whether the chart uses PD or CAL as the primary metric.
Usage
Usage note: Do not use interchangeably with clinical attachment level (CAL); PD is measured from the gingival margin, whereas CAL is measured from the cementoenamel junction.
In Context
- "The hygienist recorded a probing depth of 5 mm at the mesial aspect of tooth 14, flagging it for re-evaluation." — Periodontal chart note
- "Probing depth alone does not confirm active disease; bleeding on probing must also be assessed." — Clinical education handout