Classification of Periodontal Disease
The current classification of periodontal disease follows the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions, which categorizes periodontitis using a multi-dimensional staging and grading system rather than the previous chronic/aggressive dichotomy. 1
Current Classification Framework
1. Main Categories of Periodontal Diseases
- Periodontitis (formerly chronic and aggressive forms)
- Necrotizing Periodontal Diseases
- Periodontitis as a Manifestation of Systemic Disease
- Endodontic-Periodontal Lesions
- Periodontal Abscesses
2. Staging System for Periodontitis (I-IV)
Staging is determined by:
Severity: Based on clinical attachment loss (CAL) or bone loss (BL)
- Stage I: Initial periodontitis (1-2 mm CAL)
- Stage II: Moderate periodontitis (3-4 mm CAL)
- Stage III: Severe periodontitis with potential for tooth loss (≥5 mm CAL)
- Stage IV: Advanced periodontitis with extensive tooth loss (≥5 mm CAL)
Complexity factors that modify stage assignment:
- Probing pocket depths
- Pattern of bone loss
- Furcation involvement
- Ridge defects
- Tooth mobility/drifting
- Tooth loss due to periodontitis
Extent: Described as:
- Localized (<30% of teeth affected)
- Generalized (≥30% of teeth affected)
- Molar-incisor pattern
3. Grading System (A-C)
Grading provides information about:
Rate of progression:
- Grade A: Slow progression
- Grade B: Moderate progression
- Grade C: Rapid progression
Risk factors that influence grading:
- Smoking status
- Presence of diabetes
- Bone loss/age index
Systemic health considerations:
- Risk that periodontitis may affect systemic health
Clinical Application of the Classification
The application of this classification system follows important ground rules 2:
- Patient-based, not tooth-based: A single stage is assigned per patient based on the most severely affected tooth
- Stage can only increase: Once assigned, stage can shift upward if condition worsens but remains even after treatment
- Complexity factors must be evaluated collectively: Not in isolation
- Single grade assignment: Based on biological factors, risk assessment, and systemic health considerations
- Grade can shift in either direction: Based on changes in risk factors or disease control
Diagnostic Accuracy
The 2017 EFP/AAP classification system shows high diagnostic accuracy (92.4% sensitivity, 92% specificity) when compared with other systems such as the CDC/AAP case definition and the Community Periodontal Index (CPI) 3.
Special Considerations
Necrotizing Periodontal Diseases
These remain a distinct category characterized by:
- Papilla necrosis
- Bleeding
- Pain
- Association with host immune response impairments 1
Endodontic-Periodontal Lesions
Defined by pathological communication between pulpal and periodontal tissues, classified as:
- Acute form
- Chronic form Based on signs and symptoms that impact prognosis and treatment 1
Periodontal Abscesses
Characterized by:
- Localized pus accumulation within gingival wall
- Rapid tissue destruction
- Risk for systemic dissemination 1
Clinical Implications
This classification system provides clinicians with a framework to:
- Assess disease severity and complexity
- Evaluate risk factors for progression
- Determine appropriate treatment strategies
- Monitor outcomes over time
The multi-dimensional approach allows for more personalized patient assessment and treatment planning compared to previous classification systems that primarily focused on disease phenotypes (chronic vs. aggressive) 1, 2.
Relationship to Systemic Health
Periodontal disease has been associated with various systemic conditions:
- Increased risk of cardiovascular disease 4
- Complications in diabetes management 4
- Potential respiratory complications 5
Understanding these associations is important for comprehensive patient management and underscores the importance of proper periodontal disease classification and treatment.