Periodontitis Staging & Grading

2017 classification — Stage I–IV and Grade A–C

Interdental clinical attachment loss (worst site)

1–2 mm

3–4 mm

≥ 5 mm

Radiographic bone loss

Coronal third, < 15%

Coronal third, 15–33%

Extends to mid-third of root or beyond

Tooth loss due to periodontitis

No tooth loss from periodontitis

≤ 4 teeth lost to periodontitis

≥ 5 teeth lost to periodontitis

Case complexity (maximum probing depth / defects)

Max probing depth ≤ 4 mm, mostly horizontal bone loss

Max probing depth ≤ 5 mm

Probing depth ≥ 6 mm, vertical bone loss ≥ 3 mm, or class II/III furcation

Masticatory dysfunction, < 20 remaining teeth, or need for complex rehabilitation

Extent

Localized (< 30% of teeth)

Generalized (≥ 30% of teeth)

Molar-incisor pattern

Rate of progression (bone loss % ÷ age)

No bone loss over 5 years, or bone loss % ÷ age < 0.25 (Grade A)

Bone loss % ÷ age 0.25–1.0 (Grade B)

Bone loss % ÷ age > 1.0, or destruction exceeding expectation for biofilm (Grade C)

Smoking

Non-smoker

< 10 cigarettes/day

≥ 10 cigarettes/day

Diabetes

No diabetes

Diabetes, HbA1c < 7.0%

Diabetes, HbA1c ≥ 7.0%

Answer every item to determine stage and grade

Confirm the assigned stage against the primary staging manual before acting on it.

Evidence

Original publication

Tonetti MS, Greenwell H, Kornman KS. Staging and grading of periodontitis: Framework and proposal of a new classification and case definition. Introduced the Stage I–IV / Grade A–C system: stage from interdental clinical attachment loss, radiographic bone loss, tooth loss and case complexity; grade from the rate of progression, modified by smoking and diabetes.

Journal of Periodontology, 2018

Open source

Guideline

Caton JG, Armitage G, Berglundh T, et al. A new classification scheme for periodontal and peri-implant diseases and conditions — introduction and key changes from the 1999 classification (2017 World Workshop consensus). Extent is recorded as localized (< 30% of teeth), generalized (≥ 30%), or molar-incisor pattern.

Journal of Clinical Periodontology, 2018

Last reviewed: 2026-09

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MedScore is an educational and clinical decision-support tool. It does not provide a diagnosis, a treatment, or a drug-dosing recommendation, and it does not replace clinical judgement or local guidelines. Confirm every result against the original source before acting on it. The treating clinician remains responsible for all decisions.