Periodontal Charting Basics: Pockets, Bleeding and Attachment Loss

A periodontal chart is the record that tells you, tooth by tooth, how healthy the supporting tissues are and whether that is changing. Done well, periodontal charting turns a quick impression of "some bleeding and a few deep pockets" into numbers you can compare at the next visit, explain to the patient and use to plan treatment and recall. Done badly, it produces a page of figures nobody trusts.

This guide covers the basics every dental team should agree on: what to measure, how to record it consistently, how to read the numbers and how to turn them into a plan. It is written for dentists, hygienists and the practice managers who set up the workflow, and it complements our general dental charting guide.

What a periodontal chart records

A full periodontal chart, sometimes called a full-mouth periodontal examination, goes well beyond the restorative chart. For each tooth present it usually captures:

• Probing depth at six sites per tooth.
• Gingival margin position relative to the cementoenamel junction (CEJ), which gives recession.
• Clinical attachment level (CAL), calculated from the two values above.
• Bleeding on probing (BOP) and, where present, suppuration.
• Furcation involvement on multi-rooted teeth.
• Mobility.
• Plaque, either per site or as a whole-mouth score.
• Missing teeth, implants and relevant restorations, so the chart reads correctly.

Not every visit needs every measurement. Many clinics use a short screening at routine exams and reserve the full chart for patients whose screening suggests disease, for new patients with a periodontal history and for re-evaluation after treatment. Decide this as a team and write it down, so that "we charted perio" means the same thing whoever was in the room.

The six sites and how to probe them

Each tooth is probed at six sites: mesiobuccal, buccal (midbuccal), distobuccal, mesiolingual, lingual (midlingual) and distolingual. On the upper arch the inner surface is often called palatal instead of lingual. Walking the probe around the tooth rather than jumping between six points makes it less likely that you miss a narrow, deep defect between the recorded sites.

Technique points worth standardising

• Use the same type of probe across the team, with clear millimetre markings.
• Keep the probe parallel to the long axis of the tooth, angled slightly into the contact area for the interproximal sites.
• Use light, consistent pressure. Heavy probing overstates depths and causes bleeding that is not a sign of disease.
• Round to the nearest whole millimetre, and agree whether you round up or down when the reading falls between marks.
• Follow a fixed sequence, for example buccal of the upper arch from the patient's right to left, then palatal back again, then the lower arch the same way.

A fixed sequence matters even more when an assistant is recording while the clinician calls out the numbers. Both people must know exactly which site comes next, or values end up on the wrong surface. Calling out the tooth number at the start of each tooth is a cheap safeguard. Use one tooth numbering system throughout; our guide to FDI tooth numbering explains the two-digit codes most European clinics use.

Probing depth, recession and attachment level

These three values are related, and confusing them is the most common source of errors in periodontal charts.

Probing depth

Probing depth is the distance from the gingival margin to the base of the sulcus or pocket. As a general rule of thumb, a healthy sulcus probes at around 1 to 3 mm, and deeper readings deserve attention, especially when they bleed. Probing depth alone can mislead, however, because the gingival margin itself can move.

Gingival margin and recession

The gingival margin is recorded relative to the CEJ. When the margin has moved apically and exposed root surface, the distance is recession. When the margin sits coronal to the CEJ, for example with swollen or enlarged tissue, many charts record it as a negative value. Check how your chart or software expects the sign to be entered, because conventions differ between systems and between textbooks.

Clinical attachment level

Clinical attachment level is the distance from the CEJ to the base of the pocket, and it is the better measure of how much support has actually been lost. With recession, CAL is probing depth plus recession: a 4 mm pocket with 2 mm of recession means 6 mm of attachment loss. When the margin is coronal to the CEJ, the overlap is subtracted instead: a 5 mm pocket with the margin 2 mm above the CEJ means 3 mm of attachment loss.

This is why two patients with the same probing depths can have very different disease histories. It is also why a pocket that "improved" from 5 mm to 3 mm after treatment may partly reflect recession rather than regained attachment. Recording both values makes those changes visible.

Bleeding, furcations, mobility and plaque

Bleeding on probing and suppuration

Bleeding on probing is recorded per site, usually as present or absent, shortly after the site is probed. It is one of the most useful signs of active inflammation, and a whole-mouth bleeding score is a simple number to track between visits and to show the patient. Suppuration, pus from the pocket, is recorded separately because it points to a more active infection.

Furcation involvement

On multi-rooted teeth, the area where the roots divide can lose bone. Furcation involvement is graded by how far a furcation probe can enter horizontally, from an initial depression to a through-and-through defect. Several grading schemes exist, so record which one your clinic uses and stick to it. Furcation findings strongly influence the prognosis and treatment options for that tooth.

Mobility

Mobility is assessed by moving the tooth between two instrument handles and grading the movement, commonly on a scale from 0 (physiological) to 3 (marked movement, including vertical). Note it consistently, because increasing mobility over time is an important warning sign.

Plaque

A plaque score per site or a whole-mouth percentage shows how well home care is working. It is also the number patients can influence most directly, which makes it valuable in the conversation about what happens next.

Reading the chart and planning next steps

The chart is only useful if it leads to a decision. Once the numbers are in, look at the pattern rather than individual sites:

• Are deep pockets generalised or localised to certain teeth?
• Is attachment loss mainly interproximal, which suggests periodontitis, or mainly buccal, which can also come from brushing trauma?
• Which sites bleed, and does bleeding cluster around plaque?
• Which teeth have furcation involvement or mobility that changes their prognosis?
• How do today's values compare with the previous chart?

The 2017 classification of periodontal and peri-implant diseases, developed by the American Academy of Periodontology and the European Federation of Periodontology, describes periodontitis by stage (severity and complexity) and grade (rate of progression and risk factors such as smoking and diabetes). Your chart supplies most of the information needed for staging, together with radiographs and the patient's history. Use the published criteria rather than memory when you assign a stage and grade, and record the diagnosis in the notes so the whole team works from it.

From there, the plan typically covers home care instruction, non-surgical therapy where indicated, re-evaluation after a defined interval, referral when the case is complex, and a supportive care interval based on risk. Setting recall by risk rather than habit is covered in our article on building a dental recall system.

Making charting fast and consistent

Full periodontal charting takes time, and the temptation is to cut corners. These habits keep it accurate without making it slower:

1. Two-person charting. The clinician probes and calls out values; an assistant records. This is usually faster and cleaner than one person switching between probe and keyboard.
2. A fixed call-out format. For example, three buccal depths per tooth, then bleeding sites, then the palatal or lingual side the same way.
3. Calibration. Every so often, have two clinicians chart the same patient and compare. Differences of more than a millimetre at many sites mean technique needs aligning.
4. Same chart, same order. Use one template for the whole clinic so that comparisons over time are meaningful.
5. Review before the patient leaves. Scan the chart for impossible values, such as a depth recorded on a missing tooth.

Explaining the chart to patients

Patients rarely understand millimetres, but they understand change. Show them the sites that bleed, compare today's numbers with the last visit, and explain in plain language what a deeper pocket means for the tooth. Keep the focus on what they can do and what the clinic will do next. A clear explanation backed by their own chart is one of the most effective ways to win agreement for periodontal treatment, as we describe in our guide to treatment plan acceptance.

Frequently asked questions

How often should a full periodontal chart be done?

There is no single interval for everyone. Many clinics chart fully for new patients with signs of periodontal disease, after initial therapy at re-evaluation, and then at intervals during supportive care based on the patient's risk. Patients without signs of disease are often screened rather than fully charted at each exam.

What is the difference between probing depth and attachment loss?

Probing depth is measured from the gingival margin, which can move. Clinical attachment level is measured from the CEJ, a fixed landmark, so it shows how much support has really been lost. A shallow pocket with a lot of recession can still mean significant attachment loss.

Does bleeding on probing always mean disease?

Not always. Probing too firmly can cause bleeding in healthy tissue, which is why light, consistent pressure matters. Bleeding at the same sites over several visits, especially with plaque and deeper pockets, is a meaningful sign of inflammation.

Can implants be charted the same way?

Implants are probed and recorded too, but the readings are interpreted differently from natural teeth and compared mainly with the implant's own baseline. Record a baseline after the restoration is placed and follow your clinic's peri-implant protocol.

Key takeaways

• Record probing depth, gingival margin position and attachment level at six sites per tooth, plus bleeding, furcations, mobility and plaque.
• Attachment level, not probing depth alone, shows how much support has been lost.
• Standardise probe, pressure, sequence and sign conventions across the team.
• Read the pattern, compare with the previous chart and record the diagnosis and plan.
• Use the chart with the patient: their own numbers make the case for treatment and recall.

Periodontal care depends on good records and on patients coming back at the right interval. Pulse Dent keeps the dental chart, clinical notes, treatment plans and email reminders on the same patient record, so findings lead to a plan and a booked visit. You can take the product tour or start a free 30-day trial.