Why it has to be measured

Appearance is unreliable. Thick fibrous gum can look healthy while sitting over a deep pocket. A smoker's gums often look tight and pale precisely because the blood supply is constricted. Somebody who brushed hard for three days beforehand can suppress the bleeding temporarily.

Probing and x-rays get past that. A probe finds the depth of the space between gum and root, which tells you whether a site is cleanable at home. X-rays show the bone level, which tells you what has already gone.

One set of numbers is a snapshot. A series taken over years shows direction, and direction decides urgency.

What happens during periodontal charting

A periodontal probe is a slim instrument marked in millimeters, walked gently into the space between gum and tooth until it meets resistance.

  1. Six readings around every tooth

    Three points on the cheek side and three on the tongue side. A tooth can be healthy on its outer surface and hide a deep pocket between it and its neighbor, which is where gum disease starts.

  2. Bleeding on probing

    Whether a site bleeds when the probe reaches the base of the pocket is recorded separately from depth. Bleeding marks active inflammation, and a site that never bleeds is a reliable sign of stability.

  3. Recession measured on its own

    A tooth with three millimeters of recession and a three millimeter pocket has lost as much support as one with a six millimeter pocket and no recession, though the pocket reading looks reassuring.

  4. Mobility and furcation

    Each tooth is tested for movement and graded. Back teeth are checked at the furcation, where the roots divide, because few instruments can clean that space.

  5. Bone levels on x-rays

    These show the crest of the bone between the teeth, and the value is in comparing them against your earlier images. Digital x-rays make that straightforward at a low dose.

  6. Everything that makes cleaning harder

    Overhanging fillings, crowns that do not fit, contacts that pack food, crowding, dry mouth and tobacco all get noted. These are usually why one site keeps breaking down.

What the numbers mean

Depths are in millimeters from the gum margin to the base of the pocket, and they are always read alongside bleeding and recession.

1 to 3 mm
The normal range. A space this shallow can be cleaned at home, and with no bleeding it is a healthy site.
4 mm
Borderline, and deeper than bristles and floss reach dependably. One that never bleeds may be watched. One that bleeds every time is active.
5 mm and deeper
Beyond home care, whatever your technique. Deposits at the base have to be removed with instruments. Past about 7 mm, instruments often struggle and a periodontist may be needed.
Bleeding on probing
Recorded as the share of sites that bleed. It is the most useful marker of active disease, and a falling number across visits is the clearest evidence that treatment is working.
Recession
How far the gum has moved down the root. Added to pocket depth, it shows what a tooth has actually lost.
Attachment level
Pocket depth plus recession. The honest measure of how much foundation remains, and the number tracked over years.

Staging and grading, in plain language

The classification in current use has two dimensions. The stage, written I through IV, reflects damage already done: attachment loss, bone loss and how complicated the case is. The grade reflects how fast it appears to be moving, weighing bone loss against your age, smoking and diabetes control.

Stage says how bad it is and grade says how fast it is going. Two people at the same stage can need different treatment, because one has been stable for a decade and the other lost the same bone in three years.

You cannot stage yourself from a web page, and this is not a diagnosis. It should make your appointment more useful. Ask to see your chart, ask which sites bleed, and ask what the numbers were last time. To talk it through first, get in touch.

Questions about periodontal charting

Does probing hurt?

Healthy tissue barely registers it, since the pressure is light. Inflamed sites are tender and will bleed, so the uncomfortable parts tend to be the diseased parts. Tell the hygienist if a spot is sore, and we can numb it.

How often should this be done?

A full six-point chart at least once a year for most adults, more often if you are being treated for periodontitis. During maintenance, bleeding points are recorded every visit.

Can gum disease be seen on an x-ray alone?

Only partly. An x-ray shows bone that has already gone, mostly between the teeth, and says nothing about current inflammation or pocket depth on the cheek and tongue sides. A diagnosis needs both.

My last dentist never mentioned numbers. Should I worry?

Not necessarily, but it is worth having done. Charting habits vary between offices, and plenty of people go years without a chart while their gums stay fine. Measuring is the only way to know.