15.2 2017 AAP Classification of Periodontal Diseases
Key Takeaways
- NDEB uses 2017 World Workshop / AAP–EFP classification terminology: periodontal health, gingivitis, periodontitis (staged I–IV and graded A–C), necrotizing periodontal diseases, periodontitis as manifestation of systemic disease, and peri-implant diseases.
- Staging (I–IV) describes severity and complexity of management based primarily on interdental CAL, radiographic bone loss, tooth loss due to periodontitis, probing depths, furcations, ridge defects, and bite collapse—not on age alone.
- Grading (A–C) estimates rate of progression and risk modifiers (especially smoking and diabetes), using direct evidence (longitudinal CAL/bone loss) when available or indirect evidence (% bone loss/age) plus grade modifiers.
- The terms “chronic” and “aggressive” periodontitis from 1999 are retired as primary diagnostic labels; molar-incisor patterns are described within the staging/grading framework plus extent (localized/generalized/molar-incisor).
- Necrotizing periodontal diseases (NUG/NUP/necrotizing stomatitis) feature pain, necrosis/ulceration of papillae, and often systemic compromise; peri-implant health, mucositis, peri-implantitis, and soft-/hard-tissue deficiencies are classified separately from tooth-site periodontitis.
15.2 2017 AAP Classification of Periodontal Diseases
Quick Answer: NDEB adopts 2017 AAP/EFP (World Workshop) terminology. Classify as health, gingivitis, or periodontitis. For periodontitis, assign stage (I–IV) for severity/complexity and grade (A–C) for progression risk, plus extent (localized, generalized, or molar-incisor pattern). Know necrotizing diseases and peri-implant conditions as separate categories. Retire “chronic vs aggressive” as primary labels.
This is high-stakes AFK vocabulary. Older textbooks still say aggressive/chronic; the exam expects 2017 language. Staging answers “how bad/complex is it now?”; grading answers “how fast and with what risk modifiers?”
Classification Map (2017 Framework)
| Major category | Core idea |
|---|---|
| Periodontal health & gingival diseases/conditions | Health on intact or reduced periodontium; plaque-induced gingivitis; non–plaque-induced gingival diseases |
| Periodontitis | Necrotizing diseases; periodontitis as manifestation of systemic disease; periodontitis (the common form staged/graded) |
| Other conditions affecting the periodontium | Systemic diseases of the periodontium, abscesses, endo–perio, mucogingival deformities, traumatic occlusal forces, tooth/prosthesis-related factors |
| Peri-implant diseases & conditions | Peri-implant health, peri-implant mucositis, peri-implantitis, soft- and hard-tissue deficiencies |
Periodontal Health
Clinical gingival health can exist on an intact periodontium (no attachment/bone loss) or on a reduced periodontium (stable treated periodontitis or recession without periodontitis), provided inflammation is controlled.
| Context | Teaching points |
|---|---|
| Health on intact periodontium | ≤3 mm pockets typically; BOP in few sites (commonly taught threshold <10% bleeding sites for case definitions in workshop papers—know the principle of minimal bleeding) |
| Health on reduced periodontium (non-periodontitis) | e.g., recession from brushing; no periodontitis history |
| Health on reduced periodontium (stable periodontitis patient) | Successful therapy: no progressive CAL; shallow residual pockets; low BOP—still a periodontitis patient for lifelong maintenance even when currently healthy |
AFK pearl: a successfully treated Stage III patient with 3 mm residual depths and no BOP is in periodontal health on a reduced periodontium—not “never had periodontitis.” Maintenance intensity stays high.
Gingivitis
Dental biofilm–induced gingivitis
| Feature | Detail |
|---|---|
| Definition | Inflammation of gingiva without progressive attachment loss attributable to periodontitis |
| Clinical | Erythema, edema, BOP, possible volume increase (pseudopockets) |
| Reversibility | Yes—with plaque control and removal of local factors |
| Modifiers | Sex steroid hormones, hyperglycemia, leukemia, smoking, malnutrition, hyposalivation, prominent subgingival restorations |
| Drug-influenced | Phenytoin, CCBs, cyclosporine → enlargement |
Localized vs generalized gingivitis in workshop definitions often uses a 30% of teeth (or sites, depending on definition used) bleeding threshold for extent—exam cares more that gingivitis = inflammation without periodontitis-defining CAL patterns.
Non–plaque-induced gingival diseases (awareness list)
Genetic/developmental (hereditary gingival fibromatosis), specific infections (viral—HSV; fungal—candida; bacterial—streptococcal), inflammatory/immune conditions (lichen planus, pemphigoid, hypersensitivity), reactive processes (pyogenic granuloma), neoplasms, endocrine/nutritional/metabolic diseases, traumatic lesions, and gingival pigmentation. These are not cured by scaling alone if the primary disease is mucocutaneous or hematologic.
Periodontitis: Case Definition Threshold
A patient is a periodontitis case when detectable interdental CAL is present at ≥2 non-adjacent teeth, or buccal/oral CAL ≥3 mm with pocketing >3 mm at ≥2 teeth, and the observed CAL is not attributable solely to non-periodontitis causes (e.g., root fracture, endodontic lesion draining through periodontium, vertical root fracture, extraction-related bone loss on distal of second molar, etc.). Once a periodontitis case, apply stage, grade, and extent.
Staging (I–IV): Severity and Complexity
Stage is initially driven by severity (interdental CAL at site of greatest loss, radiographic bone loss, tooth loss due to periodontitis) and then may be shifted upward by complexity factors (deep pockets, furcations, ridge defects, bite collapse, <20 remaining teeth, etc.).
| Stage | Interdental CAL (at worst site) | Radiographic bone loss (RBL) concept | Tooth loss due to periodontitis | Complexity highlights |
|---|---|---|---|---|
| I (initial) | 1–2 mm | Coronal third (<15%) | No tooth loss | Max PD ≤4 mm; mostly horizontal bone loss |
| II (moderate) | 3–4 mm | Coronal third (15–33%) | No tooth loss | Max PD ≤5 mm; mostly horizontal |
| III (severe with potential for additional tooth loss) | ≥5 mm | Middle third of root and beyond | ≤4 teeth | PD ≥6 mm; vertical defects ≥3 mm; furcation II/III; moderate ridge defects |
| IV (severe with potential for loss of dentition) | ≥5 mm | Middle third and beyond | ≥5 teeth | All of Stage III complexity plus masticatory dysfunction, secondary occlusal trauma, severe ridge defects, bite collapse/drifting/flaring, <20 remaining teeth (10 opposing pairs) |
Extent and distribution descriptors (added to stage):
| Descriptor | Definition (workshop) |
|---|---|
| Localized | <30% of teeth involved |
| Generalized | ≥30% of teeth involved |
| Molar-incisor pattern | Classic pattern formerly often labeled “aggressive” in young patients—now described by pattern + stage/grade |
Staging rules of thumb for AFK:
- Stage on the most severe site’s CAL/RBL, then check complexity upgrades.
- Tooth loss due to periodontitis counts for staging; teeth lost to caries/ortho trauma do not automatically upstage.
- A patient needing complex rehabilitation because of periodontal breakdown is often Stage IV even if CAL numbers resemble Stage III.
- Do not stage solely by age or by “how dirty the mouth looks.”
Worked mental examples
| Scenario | Likely stage reasoning |
|---|---|
| 2 mm interdental CAL, RBL <15%, PD 4 mm, no tooth loss | Stage I |
| 4 mm CAL, RBL ~25%, PD 5 mm, no furcation | Stage II |
| 6 mm CAL, 7 mm pockets, Class II furcation, 2 teeth lost to perio | Stage III |
| 6 mm CAL, 8 teeth lost to perio, posterior bite collapse, drifting | Stage IV |
Grading (A–C): Progression Rate and Risk
Grade estimates future risk and past rate of progression. Start at Grade B, then shift to A or C based on evidence and modifiers.
Direct evidence (preferred when available)
| Grade | Longitudinal evidence |
|---|---|
| A (slow) | No CAL or RBL loss over 5 years |
| B (moderate) | <2 mm loss over 5 years |
| C (rapid) | ≥2 mm loss over 5 years |
Indirect evidence (% bone loss / age)
| Grade | % bone loss / age |
|---|---|
| A | <0.25 |
| B | 0.25–1.0 |
| C | >1.0 |
Example: 40% bone loss at age 30 → 40/30 ≈ 1.33 → Grade C indirect evidence.
Case phenotype / biofilm–destruction discrepancy
| Grade | Phenotype cue |
|---|---|
| A | Heavy biofilm deposits with low destruction |
| B | Destruction commensurate with biofilm deposits |
| C | Destruction exceeds expectations given biofilm; specific patterns (early molar-incisor) may fit |
Grade modifiers (risk factors)
| Modifier | Grade A | Grade B | Grade C |
|---|---|---|---|
| Smoking | Non-smoker | <10 cigarettes/day | ≥10 cigarettes/day |
| Diabetes | Normoglycemic / no diabetes | HbA1c <7.0% in diabetes | HbA1c ≥7.0% in diabetes |
AFK calculation pearl: always run %RBL/age when no longitudinal chart exists; then apply smoking/diabetes modifiers that can only worsen grade (A→B→C), not improve it without evidence.
Full diagnostic phrase (how to write it)
“Generalized periodontitis; Stage III, Grade C; currently unstable”
or
“Localized molar-incisor pattern periodontitis; Stage II, Grade C”
Add current status language used in practice: stable / in remission / unstable (based on BOP, progressive CAL, deep residual pockets)—exam focuses on stage/grade mechanics first.
Necrotizing Periodontal Diseases
| Entity | Clinical hallmarks | Typical host context |
|---|---|---|
| Necrotizing gingivitis (NG / NUG) | Pain, interdental papillary necrosis (“punched-out”), spontaneous bleeding, pseudomembrane, fetor; may have fever/lymphadenopathy | Stress, smoking, poor hygiene, young adults; immunocompromise |
| Necrotizing periodontitis (NP / NUP) | NG features plus attachment/bone loss | Often HIV/immunosuppression |
| Necrotizing stomatitis | Necrosis extends beyond mucogingival junction into mucosa/bone | Severe systemic compromise; medical urgency |
Management principles (preview for therapy chapter): careful debridement when tolerated, oral hygiene, chlorhexidine, address systemic factors; antibiotics (e.g., metronidazole) in selected systemic/severe cases; HIV testing consideration when presentation is atypical or recurrent.
Periodontitis as Manifestation of Systemic Disease
Some rare systemic disorders (e.g., Papillon–Lefèvre, certain immunodeficiencies, leukocyte adhesion deficiency) produce severe early periodontal breakdown as a direct manifestation. These are classified separately from common multifactorial periodontitis—recognize the pattern (child with catastrophic bone loss + systemic clues) and refer.
Other Conditions (High-Yield Mentions)
| Condition | AFK note |
|---|---|
| Periodontal abscess | Localized purulent infection in pocket; pain, swelling, deep probing, vitality often positive (vs endo abscess) |
| Endodontic–periodontal lesions | Combined pathways; vitality testing critical |
| Mucogingival deformities | Recession, lack of keratinized tissue, aberrant frena |
| Traumatic occlusal forces | Primary vs secondary occlusal trauma; widens PDL; co-factor with inflammation |
| Tooth- and prosthesis-related factors | Overhangs, open contacts, root grooves, cervical enamel projections |
Peri-Implant Conditions (Overview)
Implants lack PDL and JE architecture identical to teeth; disease terms differ.
| Diagnosis | Key features |
|---|---|
| Peri-implant health | No erythema/BOP/swelling; no bone loss beyond initial remodeling |
| Peri-implant mucositis | Inflammation of peri-implant mucosa with BOP; no progressive crestal bone loss beyond initial remodeling |
| Peri-implantitis | Inflammation plus progressive bone loss around the implant; often deeper probing, suppuration |
| Soft-/hard-tissue deficiencies | Recession, lack of keratinized mucosa, ridge defects—may exist with or without disease |
AFK contrast: mucositis ≈ reversible implant soft-tissue inflammation (like gingivitis); peri-implantitis ≈ progressive bone loss (like periodontitis analog). Probing implants is indicated but forces are gentle; baseline radiographs after prosthetic loading are essential for later comparison.
What Changed from 1999 (Exam Trap Avoidance)
| 1999-style language | 2017 approach |
|---|---|
| Chronic periodontitis | Periodontitis + stage + grade + extent |
| Aggressive periodontitis | Often molar-incisor or rapid Grade C pattern within staging |
| Periodontal health not emphasized as a category | Explicit health definitions on intact/reduced periodontium |
| Implant diseases less integrated | Dedicated peri-implant classification |
Rapid review list
- NDEB = 2017 AAP terminology
- Health / gingivitis / periodontitis triad first
- Stage I–IV = severity + complexity
- Grade A–C = rate + smoking/diabetes modifiers
- Extent: localized (<30%), generalized (≥30%), molar-incisor
- Necrotizing: pain + papillary necrosis ± attachment loss
- Mucositis (no progressive bone loss) vs peri-implantitis (with bone loss)
- “Chronic/aggressive” are outdated primary labels
Section 15.3 turns classification into a full exam: probing, BOP, mobility, furcation, and radiographs.
According to the 2017 classification used by NDEB, which pair correctly describes the two axes applied to a periodontitis case?
A 32-year-old smoker (≥10 cigarettes/day) has 40% radiographic bone loss at the worst posterior sites, interdental CAL of 6 mm, probing depths of 7 mm, Class II furcation on a molar, and two teeth previously lost to periodontitis. Using 2017 principles, the most appropriate classification framework is:
Which clinical picture best fits necrotizing gingivitis rather than routine plaque-induced gingivitis?
How does peri-implant mucositis differ from peri-implantitis in the 2017 framework?