Table 2. Rating system used by attending veterinarians as reference standard.

Stage	Description
0	Clean crowns, no evidence of gingival inflammation. No bone loss on radiographs
I	Tartar buildup, gums are slightly inflamed. No bone loss on radiographs
II	Some inflammation of the gums. Bone loss of 0–25% on radiographs
III	Inflammation of the gums along with recession or hyperplasia. Bone loss of >25%
IV	Severe gingival inflammation and recession with evidence of infection. Teeth are loose and may be missing. Large degree of bone loss on radiographs