← All explanationsPeriodontal probing depth

What do the millimetres in a gum examination mean?

Probing depth is the distance from the gum margin to the gently probed base of the sulcus or pocket. A marked periodontal probe measures it. The value is one clinical finding, not a diagnosis by itself.

For training & practice ↓

Simplified cutaway with a periodontal probe beside a tooth root; not for self-measurement. — Cutaway model · no individual measurements can be inferred

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Several sites per tooth

Different sides of a tooth may have different values. Full periodontal charting therefore records multiple sites, usually six per tooth.

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The margin can move

Swelling or recession shifts the measurement’s starting point. The same depth can therefore occur with different levels of tissue support.

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Read findings together

Bleeding, attachment, mobility and relevant radiographs add context. Repeated measurements help monitor progress.

Watch the short explanation ↓

At a glance

What are the numbers?

Measurements assigned to individual sites.

What do they show?

Depth of the accessible sulcus or pocket.

What is missing alone?

Cause, activity and the full extent of disease.

Knowledge in motion

Explained in 36 seconds.

Three steps. No audio.
Each scene can also be selected manually.

Silent educational film with German on-screen text and simplified teaching images. Not a patient case or a promised treatment outcome. The full English explanation is available below.

Read the film text in English

Several sites per tooth
Different sides of a tooth may have different values. Full periodontal charting therefore records multiple sites, usually six per tooth.
The margin can move
Swelling or recession shifts the measurement’s starting point. The same depth can therefore occur with different levels of tissue support.
Read findings together
Bleeding, attachment, mobility and relevant radiographs add context. Repeated measurements help monitor progress.

Often confused

Probing depth versus attachment loss

Probing depth starts at the movable gum margin. Attachment measurement uses a fixed reference on the tooth.

Quick answers

Does a deep reading always mean bone loss?

No. Swollen gum tissue can produce a deeper reading. Actual loss of support needs separate assessment.

Should I probe my own gums?

No. Unsuitable instruments or pressure can injure tissue; trained examination is required.

Why measure again later?

To assess treatment response and change over time. Small differences may also reflect measurement conditions.

At the practice

For a personal discussion

Editorially suggested question to discuss with Dr Niusha Barahmand Pour:

Which sites are concerning, and what do the other findings show?

Your periodontal chart can be explained in context.

Discuss pocket measurementsAppointment selection at Doctolib

Meet Dr. Niusha Barahmand Pour ↗

Learning layer for training & practiceUnderstand terminology and deepen knowledge

Pocket base: Lower extent reached by gentle probing.
Measurement site: A defined location on a tooth surface.
Gingival margin: The edge of the gum against the tooth.

Make the distinction

Probing depth starts at the movable gum margin. Attachment measurement uses a fixed reference on the tooth.

Knowledge questionWhere does probing depth begin?

For learning, not for assessing personal symptoms. Your answer is not stored or sent.

At the root tip.
At the gum margin.
At the incisal edge.

View answer

At the gum margin.

The movable gum edge is its starting point.

Sources and context

Editorial research: 2026-11-02. General information, not an individual diagnosis or treatment recommendation. Teaching illustrations are simplified and do not depict a patient case.