Periodontal probing: pockets, bleeding and attachment loss
- Examination
A thin graduated probe slid gently into the gum groove measures its depth. Deep pockets and bleeding show where periodontitis is destroying support.
See it in 3D: Gums (gingiva)
What it is
Periodontal probing measures the depth of the groove between gum and tooth at several points around each tooth with a blunt probe marked in millimetres. Healthy sulci are shallow and do not bleed. In periodontitis the attachment is destroyed and the probe goes deeper (a pocket). Clinical attachment loss, measured from the cementoenamel junction, is a better measure of lost support than pocket depth alone, because the gum may also have receded or swollen. Probing is combined with radiographs to see bone loss.
Findings and interpretation
- Up to about three millimetres with no bleeding: healthy.
- Bleeding on probing with no attachment loss: gingivitis.
- Pockets of four millimetres or more with attachment loss: periodontitis.
- Simplified screening (the Basic Periodontal Examination or Community Periodontal Index) divides the mouth into sextants and records the worst score in each.
- Absence of bleeding is a good sign of stable periodontal health.
How it is done
- Use a blunt, millimetre-marked periodontal probe with light pressure.
- Walk the probe around each tooth, recording at least six points (three on the cheek side, three on the tongue side).
- Record the deepest reading per site and whether it bleeds within seconds (bleeding on probing).
- Measure recession (gum margin below the cementoenamel junction) to calculate attachment loss.
- Check mobility of each tooth and involvement of the furcation between roots of molars.
Common mistakes
- Probing too hard causes pain and false deep readings.
- Smokers bleed less because nicotine constricts gingival vessels, so periodontitis can look deceptively quiet.
- Swollen gums can create false pockets without attachment loss (pseudopockets).
Next step / Initial management
- Bleeding without pockets: oral hygiene instruction and professional cleaning; recheck after weeks.
- Pockets with attachment loss: refer to the dentist or periodontist for staging, deep cleaning and follow-up.
- Periodontitis that is severe or progressing fast: screen for diabetes and smoking and manage them with the medical team.
Test yourself
Think of the answer, then tap the question to see it.
What finding distinguishes periodontitis from gingivitis on probing?
Clinical attachment loss with pockets, usually four millimetres or more; gingivitis bleeds but has no attachment loss.
Why may a smoker with periodontitis bleed little on probing?
Nicotine constricts the gingival vessels and masks bleeding.
What is a pseudopocket?
An apparently deep pocket caused by gum swelling without loss of attachment.
Connections
See it in 3D1
The structures of Durgical's 3D anatomy where it is found.
Educational content; it does not replace assessment by a dentist or doctor and is not a clinical instruction. For facial or neck swelling with difficulty swallowing or breathing, a knocked-out tooth or bleeding that will not stop, go to an emergency department at once.
Sources: Periodontitis (StatPearls Publishing (NCBI Bookshelf), 2023); Periodontal Disease (StatPearls Publishing (NCBI Bookshelf), 2025); Periodontal (Gum) Disease (National Institute of Dental and Craniofacial Research (NIDCR, NIH), 2024).
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Representative model, for educational purposes only.