FOUR STAGES OF PERIODONTAL DISEASE
The factors that are used to determine the severity of periodontal include the level of plaque, tartar, redness/inflammation, and damage to the teeth and surrounding soft or hard tissue.
Your veterinarian will ultimately be the one to determine your pet’s stage of periodontal disease.

Stage 1 Periodontal Disease
Stage 1 dental disease is the least severe of the disease variations. It includes some redness and inflammation of the gums (gingivitis) with some mild plaque buildup.

Stage 2 Periodontal Disease
Stage 2 dental disease is identified by redness and inflammation of the gums. It is noted with a moderate amount of plaque and dental calculus (tartar) buildup. The pet might be resistant to you trying to look at their mouth or pressing on their gums due to possible pain or discomfort.

Stage 3 Periodontal Disease
Stage 3 dental disease tends to start having a stronger odor than Stage 2, as the disease becoming far more advanced. With this stage you may start to see increased inflammation of the gums, some gum bleeding and gingival recession. There will be a heavy amount of calculus on many of the teeth. Some teeth may be loose and will wiggle if you press on them.
This stage is usually very painful, and you may start seeing some of the signs of periodontal disease that are listed above. Once a pet’s teeth get to this stage, there will likely be a few extractions of badly diseased teeth.

Stage 4 Periodontal Disease
Stage 4 dental disease is characterized by very red and inflamed diseased gums and a very foul odor. There will be significant gum recession, mild to severe gingival bleeding, and sometimes pus will be present.
Most or all of the teeth will have significant dental calculus. Some teeth will be very loose, and sometimes Stage 4 teeth are so diseased that they will only be hanging on by their roots.
A pet with Stage 4 dental disease will be in a lot of pain, but may still continue to eat (even hard food) for years after the progression of this disease. Dental disease this severe often requires many extractions. Sometimes all of the teeth must be extracted if the disease is too severe.