1. Stages of Periodontal Disease
Artwork used by permission from Pfizer Animal Health

2. No gingival inflammation or periodontitis clinically evident
PD0 Normal
Clinically normal
No gingival inflammation or periodontitis clinically evident
Periodontal Disease Classification, Date accessed 08/29/2010

3. Gingivitis only without attachment loss
PD1 Stage 1 Gingivitis
Gingivitis only without attachment loss
Height and architecture of the alveolar margin are normal
Periodontal Disease Classification, Date accessed 08/29/2010

4. PD2 Stage 2 Early Periodontitis
Less than 25% of attachment loss or at most there is a stage 1 furcation involvement in multirooted teeth.
Early radiologic signs of periodontitis
Attachment loss measured either by probing of the clinical attachment level or the radiographic distance of the alveolar margin from the cemento-enamel junction relative to the length of the root.
Periodontal Disease Classification, Date accessed 08/29/2010

5. Stage 3 PD3 Moderate Periodontitis
25-50% of attachment loss measured either by periodontal probe or radiologic measurement.
Stage 2 furcation involvement in multi-rooted teeth.
Periodontal Disease Classification, Date accessed 08/29/2010

6. PD4 Stage 4 Advanced Periodontitis
More than 50% attachment loss measured by periodontal probe or radiologic measurement
Stage 3 furcation involvement of multi-rooted teeth
Periodontal Disease Classification, Date accessed 08/29/2010