Why measuring matters

Appearance on its own is unreliable. Thick fibrous gum can look healthy while sitting over a deep pocket. Gums affected by nicotine often look tight and pale precisely because the blood supply is constricted. Bleeding can also vary from one week to the next for reasons that have little to do with how much disease is present.

Probing and x-rays resolve that uncertainty. A probe finds the depth of the space between gum and root, which indicates whether a site can be cleaned at home. X-rays show the bone level, which records what has already been lost.

One set of numbers gives a single point in time. A series taken over several years shows which way things are moving, and that is usually what determines how urgent treatment is.

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 still hide a deep pocket between it and its neighbor, which is where gum disease often starts.

  2. Bleeding on probing

    Whether a site bleeds when the probe reaches the base of the pocket is recorded separately from the depth. Bleeding marks active inflammation, and a site that consistently does not bleed is a good sign of stability.

  3. Recession measured on its own

    A tooth with three millimeters of recession and a three millimeter pocket has lost about as much support as one with a six millimeter pocket and no recession, even though the pocket reading looks more 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 that space is difficult for any instrument to clean.

  5. Bone levels on x-rays

    These show the crest of the bone between the teeth, and much of the value lies in comparing them against your earlier images. X-rays make that comparison straightforward.

  6. Everything that makes cleaning harder

    Overhanging fillings, crowns that fit poorly, contacts that trap food, crowding, dry mouth and tobacco use are all noted. These are often the reason one particular 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 usually be cleaned at home, and with no bleeding it is a healthy site.
4 mm
Borderline, and deeper than bristles and floss reach dependably. A site that does not bleed may be watched. One that bleeds every time is active.
5 mm and deeper
Beyond the reach of home care, regardless of 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 a useful marker of active disease, and a falling number across visits is good evidence that treatment is working.
Recession
How far the gum has moved down the root. Added to pocket depth, it shows the total support a tooth has lost.
Attachment level
Pocket depth plus recession. This is the measure of how much foundation remains, and it is the number to track over years.

How staging and grading work

The classification in current use has two dimensions. The stage, written I through IV, reflects the 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 describes how far the disease has progressed, and grade describes how quickly. Two people at the same stage can need different treatment, because one may have been stable for a decade while the other lost the same bone in a few years.

Your own stage and grade come from an examination, and knowing the terms can make your appointment more productive. Ask to see your chart, ask which sites bleed, and ask what the numbers were last time. To discuss it beforehand, 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 areas tend to be the diseased areas. Let your hygienist know if a spot is sore, and the area can be numbed.

How often should this be done?

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

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

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

I have never had my gums measured. Should I worry?

Not necessarily, but the measurement should be done. Many people go years without a periodontal chart and their gums remain healthy. Measuring is the only way to establish where you stand, so it is a reasonable request at your next visit.