Clinical terms and classifications of periodontal disease in veterinary medicine

The degree of severity of periodontal disease relates to a single tooth; a patient may have teeth that have different stages of periodontal disease. Here is an outline of the American Veterinary Dental College-approved periodontal disease classifications.

Normal (PD 0): Clinically normal — no gingival inflammation or periodontitis clinically evident.

Stage 1 (PD 1): Gingivitis only without attachment loss. The height and architecture of the alveolar margin are normal.

Stage 2 (PD 2): Early periodontitis — less than 25 percent of attachment loss, or, at most, there is a stage 1 furcation involvement in multirooted teeth. There are early radiologic signs of periodontitis. The loss of periodontal attachment is less than 25 percent as measured either by probing of the clinical attachment level or radiographic determination of the distance of the alveolar margin from the cemento-enamel junction relative to the length of the root.

Stage 3 (PD 3): Moderate periodontitis — 25 to 50 percent of attachment loss as measured either by probing of the clinical attachment level or radiographic determination of the distance of the alveolar margin from the cemento-enamel junction relative to the length of the root, or there is a stage 2 furcation involvement in multirooted teeth.

Stage 4 (PD 4): Advanced periodontitis — more than 50 percent of attachment loss as measured either by probing of the clinical attachment level or radiographic determination of the distance of the alveolar margin from the cemento-enamel junction relative to the length of the root, or there is a stage 3 furcation involvement in multirooted teeth.

*Source: Wolf HF, Rateitschak EM, Rateitschak KH, et al. Color atlas of dental medicine: periodontology. 3rd ed. Stuttgart: Georg Thieme Verlag, 2005.

Furcation Involvement/Exposure

Stage 1 (F1, furcation involvement) exists when a periodontal probe extends less than half way under the crown in any direction of a multirooted tooth with attachment loss.

Stage 2 (F2, furcation involvement) exists when a periodontal probe extends greater than half way under the crown of a multirooted tooth with attachment loss but not through and through.

Stage 3 (F3, furcation exposure) exists when a periodontal probe extends under the crown of a multirooted tooth, through and through from one side of the furcation out the other.

Tooth Mobility

Stage 0 (M0) — Physiologic mobility up to 0.2 mm.

Stage 1 (M1) — The mobility is increased in any direction other than axial over a distance of more than 0.2 mm and up to 0.5 mm.

Stage 2 (M2) — The mobility is increased in any direction other than axial over a distance of more than 0.5 mm and up to 1.0 mm.

Stage 3 (M3) — The mobility is increased in any direction other than axial over a distance exceeding 1.0 mm or any axial movement.