Gum disease.
What a pocket is, why the millimetres matter, and which cleaning goes with which number.
The four stages, side by side.
Left to right: the pocket gets deeper, tartar spreads down the root, and the bone drops.
Your toothbrush only gets 2mm down.
Floss gets about 3mm. Past that, nothing you own reliably reaches the bottom. So a deep pocket is not just a bigger number. It is a spot you cannot keep clean, no matter how hard you try. That is the whole problem.
Healthy
Your brush and floss still reach the bottom. You can keep it clean yourself.
The tipping point
Nothing you own reliably reaches the bottom anymore.
Deep cleaning territory
Bacteria sit on the root until a professional cleaning removes them.
If you had a deep cleaning, read this part
A deep cleaning is the start, not the end. Two cleanings a year is no longer enough. The bacteria grow back down into the pocket in a few months. Each time they do, you risk losing a little more bone, and bone does not come back on its own.
So you come back more often, usually every three to four months. Your dentist sets the exact gap based on how your gums do. It is the thing that holds the line. People who skip it usually end up right back where they started, with less bone than before.
The reset
Clears the pocket out. Pockets usually get somewhat shallower as the gum heals, but the lost bone underneath does not rebuild itself.
The bacteria grow back
Roughly how long they need to reach the bottom of the pocket again.
Maintenance gets there first
That visit is what holds the line, for as long as you keep it.
Try it. Drag the probe.
The same measurement, on one tooth. Slide from 1 to 9 millimeters and watch the diagnosis change.
Cross-section of one tooth. Each square on the grid is 1 millimeter.
Your brush can reach the bottom of this space.
Healthy gums
The gum hugs the tooth and the space between them is shallow. Nothing is damaged.
A regular cleaning, usually every 6 months.
- PD
- 2 mm
- CAL est.
- 0 mm
Clinical gingival health (2017 World Workshop).
Suggested CDT: D1110 prophylaxis.
Grade (A to C) is set by progression rate, smoking and diabetes. It is not modeled here. Bleeding, recession and extent come from a full exam, not from one depth.
Sources and limits of this page.
- Staging. The 2017 World Workshop system, co-presented by the American Academy of Periodontology and the European Federation of Periodontology. AAP, Staging and Grading Periodontitis, from Tonetti, Greenwell and Kornman, Journal of Periodontology 2018;89(Suppl 1):S159-S172.
- Treatment steps and targets. Pockets at 4mm or less with no bleeding on probing, per the EFP S3 level clinical practice guideline for stage I to III periodontitis.
- Gingivitis is its own diagnosis, separate from periodontitis rather than an early stage of it. It is called localized or generalized by how much of the mouth bleeds.
- Recall intervals are individual. A 2 to 4 month recall is reasonable in moderate to advanced cases, set by risk rather than by a fixed rule.
- The model simplifies. It ties each depth to one diagnosis so the idea is teachable. Real staging also uses bleeding, recession, x-rays, and how many teeth are involved. The brushing and flossing reach figures are approximate and vary with technique.
Want to know your own numbers?
A full periodontal exam measures six spots on every tooth and shows you where you stand.