Periodontal Charting Manual
A practical, clinician-focused guide to periodontal charting: what to record, how to probe, and how to interpret the numbers. Written to be useful whether you use Zermmi or not — the indices, thresholds, and workflow advice apply to any periodontal chart.
A practical, clinician-focused guide to periodontal charting: what to record, how to probe, and how to interpret the numbers. Written to be useful whether you use Zermmi or not — the indices, thresholds, and workflow advice apply to any periodontal chart.
What is periodontal charting?
Periodontal charting is the systematic recording of clinical measurements around every tooth to assess the health of the periodontium — the gingiva, periodontal ligament, cementum, and alveolar bone. A complete chart captures pocket depth, bleeding on probing, recession, furcation involvement, mobility, and plaque at six sites per tooth (mesio-buccal, mid-buccal, disto-buccal, mesio-lingual, mid-lingual, disto-lingual).
These measurements, together with radiographs and medical history, let you stage and grade periodontitis according to the 2017 World Workshop classification and plan treatment and recall accordingly. Charts are also the single most reliable way to demonstrate progression or stability between visits — which is why a clean, comparable, longitudinal record matters more than any individual measurement.
A good chart is:
- Complete. Every site, every visit. Missing data defeats comparison.
- Reproducible. Same probe, same force, same technique, same reference point.
- Comparable. Aligned tooth positions and consistent notation so past and present charts can be diffed at a glance.
- Communicable. Legible to a colleague, a hygienist, a specialist referral, and — via a printed summary — to the patient themselves.
Indices you record on a periodontal chart
This section is a reference for the six core measurements you'll capture. Each one answers a different clinical question, and together they form the basis of staging and grading.
Probing depth (PD)
The distance from the gingival margin to the base of the sulcus or pocket, measured in millimetres with a calibrated periodontal probe (commonly the UNC-15 or WHO-621). Six sites per tooth, recorded as whole millimetres — most charts don't resolve finer because probing isn't that reproducible.
- 1–3 mm: physiological sulcus.
- 4–5 mm: shallow pocket, early disease or active inflammation.
- ≥6 mm: deep pocket, significant attachment loss, likely requires non-surgical or surgical intervention.
Probing force matters. The literature converges on ~0.20–0.25 N (roughly the pressure needed to blanch a fingernail bed). Force-controlled probes exist; most clinicians rely on calibrated technique.
Bleeding on probing (BOP)
A binary per-site measurement: did the site bleed within 10–30 seconds of probing? BOP is the most sensitive early indicator of gingival inflammation. It's also the single best negative predictor: consistent absence of BOP over multiple visits strongly suggests periodontal stability.
Report BOP as a percentage of sites bleeding out of all sites charted. Under 10% is the widely cited target for periodontal health after treatment.
Clinical attachment level (CAL) and recession
CAL is the distance from the cemento-enamel junction (CEJ) to the base of the pocket. It's the closest clinical proxy we have for actual attachment loss because, unlike PD, it's independent of gingival margin position. If recession is present, CAL = PD + recession. If the gingiva sits coronal to the CEJ, CAL = PD − (gingival margin distance coronal to CEJ).
Most chairside workflows record PD and recession separately and compute CAL. That's fine — just make sure recession is always recorded with the correct sign and reference.
Mobility
Graded 0–3 using Miller's classification:
- 0: physiological mobility only.
- 1: up to 1 mm horizontal movement.
- 2: more than 1 mm horizontal movement.
- 3: horizontal and vertical (depressible) movement.
Use two rigid instrument handles (not fingers) applied buccally and lingually. Mobility that increases between visits is a red flag even if pockets look stable.
Furcation involvement
Applicable only to multi-rooted teeth. Graded using a Nabers probe:
- Class I: horizontal loss up to one-third of the tooth width.
- Class II: horizontal loss beyond one-third but not through-and-through.
- Class III: through-and-through furcation.
Furcations are undertreated in most workflows because they're hard to probe. A chart that consistently records furcations catches problems that PD alone misses.
Plaque index
Usually recorded as a binary per-site score (O'Leary) or on a 0–3 scale (Silness-Löe). Plaque and BOP together drive the oral hygiene conversation with the patient. A plaque score below 20% is a reasonable target during active therapy.
How to perform a periodontal examination
A complete periodontal examination takes 8–15 minutes per full mouth once the clinician has a settled workflow. The time is invested once; the comparable longitudinal record it produces pays back at every subsequent recall.
Patient positioning and preparation
Recline the chair so the maxilla is roughly horizontal when you work upper teeth, and closer to 45° for the mandible. Good light on the working field and a suction line within reach of the assistant matter more than fancy equipment. Dry the area you are about to probe — wet gingiva masks bleeding for the first few seconds and leads to under-reporting of BOP.
Update the medical history before you start charting, not after. Smoking, diabetes (and HbA1c if known), pregnancy, anticoagulants, and recent antibiotics all change how you interpret the numbers you're about to record. Take intra-oral photographs or radiographs first if they're due — probing can induce transient bleeding that photographs badly.
Probe selection and calibration
Use a single probe type for the whole visit and ideally for the whole patient's history. Mixing a UNC-15 with a Williams probe between visits introduces noise that looks like disease progression. The UNC-15 (1 mm markings throughout) is the most common choice; the WHO-621 probe with its 0.5 mm ball tip is the right pick when you also want to screen for calculus. For furcations, a curved Nabers probe is non-optional.
Probing force should sit at roughly 0.20–0.25 N. The tactile reference most clinicians use is the pressure required to blanch a fingernail bed — a little less than you probably think. Force-controlled pressure-sensitive probes exist (e.g. the Florida Probe, the Click-Probe) and are worth the investment in specialist settings, but calibrated manual technique is acceptable and more common.
Sequencing
Two defensible orders:
- Quadrant-by-quadrant, six sites per tooth — probe disto-buccal, mid-buccal, mesio-buccal, then mesio-lingual, mid-lingual, disto-lingual, one tooth at a time. Best for paper charts or when the assistant writes while the clinician probes.
- Site-by-site across the arch — probe all disto-buccals first, then all mid-buccals, and so on. Faster once you're calibrated and well suited to auto-advancing digital charts like Zermmi, where the cursor moves to the next expected site after each entry and the clinician never looks down at the screen.
Either sequence is fine. The rule is pick one and use it every visit, for every patient. Changing sequence between visits multiplies measurement variability.
Common pitfalls
- Under-probing line angles. The mesio-buccal and disto-buccal sites are where pockets hide. Angle the probe slightly into the embrasure rather than keeping it perpendicular to the tooth's long axis.
- Skipping lingual and palatal sites. Uncomfortable for the patient, easy to rush. Chart them anyway — lingual disease is often asymmetric and diagnostic.
- Not drying before BOP. Wait 10–30 seconds after probing before declaring a site non-bleeding. Early readings systematically under-report.
- Reading PD from the gingival margin when recording CAL. CAL references the CEJ, not the margin. If you record PD and recession separately the charting software can compute CAL correctly; most errors happen when clinicians try to mentally combine them in real time.
- Charting from memory. Either a second pair of hands writes, or the clinician enters values themselves after each site. Batching "I'll remember and enter it later" leaks data and introduces round-number bias.
Interpreting the chart: staging and grading
The 2017 World Workshop classification (Papapanou et al., J Clin Periodontol 2018; Tonetti et al., J Periodontol 2018) is the current international standard. It replaces the 1999 chronic/aggressive split with a two-axis framework: stage (severity and complexity) and grade (rate of progression and risk).
Staging
Stage is driven primarily by interdental CAL at the worst-affected site, radiographic bone loss, and tooth loss attributable to periodontitis.
- Stage I — initial periodontitis. Interdental CAL 1–2 mm, radiographic bone loss in the coronal third (<15%), no tooth loss from periodontitis, max PD ≤4 mm, mostly horizontal bone loss.
- Stage II — moderate. Interdental CAL 3–4 mm, bone loss in the coronal third (15–33%), no tooth loss from periodontitis, max PD ≤5 mm, mostly horizontal bone loss.
- Stage III — severe with potential for additional tooth loss. Interdental CAL ≥5 mm, bone loss extending to mid-third of root and beyond, tooth loss due to periodontitis ≤4 teeth. Complexity factors: PD ≥6 mm, vertical bone loss ≥3 mm, furcation class II or III, moderate ridge defects.
- Stage IV — advanced with extensive tooth loss and complex rehabilitation needs. Stage III criteria plus tooth loss due to periodontitis ≥5 teeth, masticatory dysfunction, secondary occlusal trauma (mobility ≥2), severe ridge defect, bite collapse, drifting, flaring, less than 20 remaining teeth (10 opposing pairs).
A single advanced site can move the stage up. Err on the side of the higher stage when the patient is on the boundary.
Grading
Grade describes how fast the disease has moved and how likely it is to move further. Three anchors:
- Grade A — slow rate. No bone loss or CAL increase over 5 years, or the radiographic bone loss (% of root length) divided by age is <0.25. Non-smoker. Normoglycaemic.
- Grade B — moderate rate. <2 mm bone loss or CAL gain over 5 years, or %BL/age between 0.25 and 1.0. Smoker <10 cigarettes/day. HbA1c <7.0% in diabetics.
- Grade C — rapid rate. ≥2 mm bone loss or CAL gain over 5 years, or %BL/age >1.0. Smoker ≥10 cigarettes/day. HbA1c ≥7.0% in diabetics.
When longitudinal data isn't available, grade from the indirect evidence: %BL/age is a reasonable single proxy.
Extent and distribution
Add a descriptor:
- Localised — <30% of teeth involved.
- Generalised — ≥30% of teeth involved.
- Molar-incisor pattern — the characteristic distribution of what used to be called aggressive periodontitis.
Worked example
A 52-year-old non-smoker, non-diabetic presents with: worst-site interdental CAL 6 mm on tooth 26, three teeth lost to periodontitis, furcation class II on 16 and 26, max PD 7 mm, mostly horizontal bone loss on radiographs, 45% of teeth involved. Diagnosis: generalised periodontitis, Stage III, Grade B.
Implants and peri-implant charting
Implants need charting too — the measurements are similar, the thresholds are not.
What's different
- No CEJ reference. Probing depths around implants are read from the mucosal margin or the implant shoulder, depending on the prosthetic design. Record the reference point you used so the next clinician can reproduce it.
- Baseline matters more. A 4 mm pocket around an implant may be physiological for that implant and pathological for another, depending on the connection geometry, soft-tissue thickness at placement, and time since loading. The single most useful number in peri-implant charting is the change from the baseline chart — typically taken at prosthetic delivery or the first maintenance visit.
- Lighter probing force. Around 0.15 N is the commonly cited target — roughly two-thirds of the force you'd use on a natural tooth. Harder probing can penetrate the sulcular epithelium and produce falsely deep readings.
- BOP is graded differently. Around implants, BOP is reported alongside suppuration: bleeding with suppuration is a stronger peri-implantitis indicator than bleeding alone.
Peri-implant mucositis vs. peri-implantitis
- Peri-implant mucositis — bleeding on probing with or without increased PD, but no additional bone loss beyond the initial crestal remodelling. Reversible with non-surgical debridement and improved hygiene.
- Peri-implantitis — bleeding and/or suppuration on probing, PD ≥6 mm, and progressive bone loss ≥3 mm from the initial radiograph (or ≥2 mm if no baseline is available). Requires surgical intervention in most cases.
Radiographic bone-level reference
Record the first-thread-exposure level at baseline. Subsequent bone loss is measured from this reference, not from the implant shoulder. A standardised periapical with a paralleling device gives reproducible linear measurements; CBCT is appropriate when surgery is on the table.
Recall intervals
Peri-implant maintenance is typically every 3–4 months in the first year after loading, moving to every 6 months in year two if mucositis is absent and plaque control is good. Smokers and reconstruction cases stay on the shorter interval indefinitely.
Longitudinal comparison and progression
A single chart is a snapshot. A periodontal diagnosis is a trajectory. The whole point of standardising your charting workflow is that you can compare two charts, nine months apart, and see which sites have moved.
What a good two-visit diff looks like
Same tooth numbering, same reference points, same probe, same operator if possible. Line the two charts up — most software, including Zermmi, will overlay them — and scan for:
Percentage Trends
Pocket Depth Trends
Deep Sites Trend
CAL Trends
- Green sites — PD decreased, BOP resolved. Expected after successful non-surgical therapy or a good maintenance interval.
- Yellow / stable — PD within ±1 mm, BOP unchanged. The goal for most recall patients.
- Red sites — PD increased ≥2 mm, new BOP, new furcation involvement, mobility increase. These are the sites that warrant attention, independent of the patient's overall picture.
A 1 mm PD fluctuation at a single site is within measurement error. Two or more adjacent sites all showing a 1 mm increase is a real signal, not noise.
Red flags
- Localised rapid PD increase at one site while the rest of the mouth is stable — often a root fracture, endo-perio lesion, or retained fragment, not primary periodontitis.
- New BOP at previously stable sites — early inflammation that hasn't yet translated to PD change. Treat now, not at the next recall.
- New furcation involvement — the single most predictive finding for future tooth loss.
- Mobility increase without occlusal explanation — bone loss progression, check radiographs.
When to re-chart
- End of active therapy — baseline for maintenance phase.
- Every supportive periodontal therapy visit — typically every 3, 4, or 6 months depending on risk.
- Before any surgical referral — the specialist needs comparable numbers.
- Before and after any major life event — pregnancy, new systemic diagnosis, smoking cessation, orthodontics.
Summary
Bleeding on Probing
15%
Plaque
8%
Suppuration
2%
Mean Depth
2.4mm
Sites ≥4mm
12%
Deepest
6mm
Patients respond strongly to visual comparison. A side-by-side chart showing a site moving from 7 mm red to 4 mm green is the most persuasive argument for hygiene compliance you will ever make in a chair.
Recall intervals and supportive periodontal therapy
Supportive periodontal therapy (SPT) is the single strongest predictor of long-term tooth retention in treated patients — stronger than the initial severity of disease or the type of active therapy delivered.
Risk stratification
The Lang & Tonetti periodontal risk assessment (Oral Health Prev Dent 2003) scores six factors and triages patients into low, moderate, or high risk:
- Percentage of sites with BOP.
- Prevalence of residual pockets ≥5 mm.
- Number of lost teeth (out of 28, excluding third molars).
- Loss of periodontal support relative to the patient's age (%BL/age).
- Systemic and genetic conditions (diabetes, IL-1 genotype where available).
- Environmental factors (smoking, in pack-years).
The six scores combine into a radar chart; the size and shape of the polygon determine the category.
Typical intervals
- Low risk — 12 months.
- Moderate risk — 6 months.
- High risk — 3–4 months.
- Very high risk or active inflammation — stay on 3 months indefinitely until the picture improves.
These are defaults, not rules. A 3-month recall for a compliant low-risk patient is over-servicing; a 6-month recall for a smoker with residual 6 mm pockets is negligent.
What gets re-recorded at each SPT visit
Full six-site probing, BOP, plaque, and mobility every visit. Radiographs every 2–3 years, or sooner if PD or mobility have changed. Furcations at every visit once they've been identified. Re-chart the full classification (stage and grade) annually — stage can rise, grade can shift, and the diagnosis should reflect it.
Exporting and sharing your chart
PDF for the patient and the referral network
A printable one-page summary with the chart, the diagnosis line, and the key risk factors is the single most-used export in most practices. Patients keep them. Referrals read them. Zermmi generates a professional PDF from any chart with one click — the layout is designed to be legible without the clinician's verbal commentary, which is the test most chart exports fail.
Integrations and data portability
If your practice management system accepts periodontal data through an API or a structured CSV, use it. If not, attach the PDF to the patient record and move on — pixel-perfect integration is a nice-to-have, portability of the underlying diagnosis is essential. Patients are entitled under GDPR (EU) and HIPAA (US) to a copy of their clinical record in a machine-readable form on request, and periodontal charts count.
Multi-practitioner and multi-location practices
Keep the same charting tool across all chairs. The single most common source of longitudinal inconsistency in multi-chair practices is different hygienists using different conventions in different software. Pick one, document the reference points you use, and require everyone on the team to use it the same way.
Using Zermmi for periodontal charting
Zermmi is built around the workflow described in this manual. The choices that matter for day-to-day clinical use:
- Auto-advance between sites. Enter a value, the cursor moves to the next expected site, you keep your eyes on the patient and the probe. Works for either sequencing style described above.
- Realistic tooth visualisation. The chart shows anatomically-correct tooth shapes and renders recession, pocket depth, and furcation involvement as visible geometry — not just numbers in boxes. This matters for patient-facing conversation at chair-side.
- Per-patient history with side-by-side comparison. Any two charts from the same patient can be overlaid to produce the green/yellow/red diff described in the longitudinal section above.
- Instant summary statistics. Mean PD, mean CAL, BOP%, plaque% computed live as you chart. The summary updates before you've finished the second arch, which is the only useful time for it to update.
Instant Summary
Real-time calculation of key periodontal metrics
Bleeding
Plaque
Pocket Depth
Sites >4mm
Calculations update automatically as you chart
- Professional PDF export. One click, one page, ready for referral or patient handout. No login required for single-visit use.
- Multilingual. 18 languages, including the main European, East Asian, and Middle Eastern locales. Patient handouts in the patient's language close the comprehension gap that English-only charting tools create.
Professional Branding
Downtown Dental Care
Dental Practice
Contact Information
Start charting, free and without registration, at /periochart.
Further reading
- Papapanou PN, et al. Periodontitis: Consensus report of workgroup 2 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J Clin Periodontol. 2018.
- Tonetti MS, Greenwell H, Kornman KS. Staging and grading of periodontitis: Framework and proposal of a new classification and case definition. J Periodontol. 2018.
- Lang NP, Tonetti MS. Periodontal risk assessment (PRA) for patients in supportive periodontal therapy (SPT). Oral Health Prev Dent. 2003.