Table 1. Classification of periodontal diseases into four stages 16.
| Periodontitis stage | Stage I | Stage II | Stage III | Stage IV | |
|---|---|---|---|---|---|
| Severity | Interdental CAL at site of
greatest loss |
1–2 mm | 3–4 mm | ≥5mm | ≥5mm |
| Radiographic bone loss | Coronal third (<15%) | Coronal third
(15% to 33%) |
Extending to middle or apical third of the root | ||
| Tooth loss | No tooth loss due to periodontitis | Tooth loss due to
periodontitis of ≤4 teeth |
Tooth loss due to
periodontitis of ≤5 teeth |
||
| Complexity | Local | - Maximum probing depth
≤4mm. - Mostly horizontal bone loss |
- Maximum
probing depth ≤5mm. - Mostly horizontal bone loss |
In addition to Stage II
complexity: - Probing depth ≥6mm. - Vertical bone loss ≥3mm. - Furcation involvement class II or III - Moderate ridge defect |
In addition to Stage
III complexity: Need for complex rehabilitation due to: - Masticatory dysfunction - Secondary occlusal trauma (tooth mobility degree ≥2) - Severe ridge defect - Bite collapse, drifting, flaring - Less than 20 remaining teeth (10 opposing pairs) |
CAL, clinical attachment loss.