There are three stages of periodontitis:

Stage 1 – Early Periodontitis (Early Bone Loss) If plaque irritation persists untreated, it causes the attachment of the gum to move down the root. This “creeping” of the gum attachment makes the crevice deeper. A crevice more than 3 mm deep is considered a pocket. Pockets are very hard to keep clean. They are impossible to keep clean once calculus has formed within them. The toxins from the plaque in the pocket shown opposite have also destroyed some adjacent bone. Professional treatment plus good home care can slow or stop the progress of disease at this stage.

Stage 2 – Moderate Periodontitis (Moderate Bone Loss) Continuing infection has caused the loss of up to one third of bone support, as the gum attachment has crept further down the root. Pockets depths usually range from 5 to 6 mm. Usually at this stage, there will be some slight mobility of the tooth, which may be noticed by the patient. This does not mean that the tooth is falling out, but does indicate that treatment is required to prevent eventual loss of the tooth. Professional treatment plus good home care can stop the progress of disease at this stage, and will probably allow the tooth to firm up again in its socket, and remain healthy for the long term. There will, however, probably be some noticeable and permanent gingival recession.

Stage 3 – Severe Periodontitis (Advanced Bone Loss) Half or more of the original bone holding the tooth has been lost and pockets usually are 7 mm or deeper. The margin of the gum may withdraw down the root. This recession of the gums exposes part of the root and makes the tooth look longer.
Tooth mobility is usually much more noticeable at this stage, and difficult to reverse. Even in this advanced stage of periodontal disease, professional treatment and proper home care usually help considerably. In some cases it is possible to replace lost bone by using advanced surgical techniques.