2017 Staging of periodontitis: Reflects severity, complexity, and extent of periodontitis.
Stage 1 (mild) to stage 4 (severe, tooth loss, complex management)
Stage is determined by worst of the severity/complexity/bone loss.
Complexity factors → can determine whether a disease can be staged higher due to complexities with treatment:
In clinical practice, the identification of complexity factors ensures that staging reflects not only the extent of tissue destruction, but also the practical challenges involved in managing the disease.
Complexity factors are particularly important in distinguishing Stage III from Stage IV periodontitis. While both stages represent severe periodontal destruction, Stage IV disease is characterised by additional functional problems such as bite collapse, severe tooth mobility, or extensive tooth loss requiring multidisciplinary treatment planning.
Recognising these factors allows clinicians to:
anticipate the difficulty of periodontal therapy
identify cases requiring specialist referral
plan comprehensive multidisciplinary care
Common complexity factors include:
Probing depth ≥6 mm
Vertical bone loss ≥3 mm
Furcation involvement (Class II or III)
Moderate ridge defects
Tooth mobility ≥2, bite collapse
Secondary occlusal trauma
<20 remaining teeth (stage IV)
Tooth loss for staging:
Stage 1-2 → No tooth loss due to periodontitis
Stage 3 → Loss of ≤4 teeth due to periodontits
Stage 4 → Loss of ≥5 teeth due to periodontitis
Severity of bone loss:
Stage | Definition - interproximal bone loss required |
|---|---|
1 | Early/mild - coronal third (<15%) (or <2mm attachment loss from CEJ) |
2 | Moderate - coronal third of root (15-33%) |
3 | Severe - Extending to the middle third of root |
4 | Very severe - Extending to the apical third of root |