What Do the Numbers Mean at the Dentist? Gum Measurements, Explained

You're reclined in the chair, and you hear numbers like your hygienist is calling out lottery results: "Three, two, three. Four, three, four."

Most patients have no idea what's happening. Some assume it's a grade. (It's not — nobody's failing.) It's called periodontal charting, or perio charting, and it's one of the most useful few minutes of your entire visit. Here's what we're actually doing.

What is perio charting?

Your gums don't attach to your teeth right at the edge you can see. There's a shallow cuff of gum tissue around each tooth — think of it like a turtleneck collar. We measure how deep that cuff is with a perio probe, which is basically a tiny ruler marked in millimeters.

We take that measurement at six spots around every tooth and write each one down. We also note anything else your gums are telling us: bleeding, recession, teeth that move more than they should. Start to finish, it takes a few minutes.

What do the numbers actually mean?

The number is the depth of that cuff — the "pocket" — in millimeters.

1 to 3 mm is healthy. Your toothbrush and floss can reach the bottom of a pocket that shallow, so bacteria never get a foothold.

4 mm is the watch zone. It might be temporary inflammation that tightens back up with better home care, or it might be the start of something. Context matters here — more on that below.

5 mm and up is where problems live. You physically can't clean the bottom of a pocket that deep at home; bristles and floss don't reach. Bacteria settle in undisturbed, the gum stays inflamed, and over time the bone holding the tooth can start to break down.

Bleeding matters as much as depth. A 4 that bleeds when we touch it is telling a different story than a 4 that doesn't. Healthy gums generally don't bleed from the light pressure of a probe.

Why do you measure my gums every year?

Because gum disease is quiet. It doesn't hurt until it's advanced, there's a reason it gets called silent. Nearly half of American adults over 30 have some form of it, and most don't know.

The numbers give us a trendline. A tooth that reads 3 this year, 4 next year, and 5 the year after is telling us a story long before anything hurts. Caught at a 4, the fix might be a tweak to your flossing and a recheck. Caught at a 6, we're treating actual disease and bone loss that doesn't grow back on its own.

That's the whole point: measuring lets us catch things while they're still small and boring.

Does perio charting hurt?

It shouldn't. The probe slides gently into the pocket with very light pressure — it's a measurement, not a poke. If a spot is tender, that's your gums pointing to a problem, not the probe causing one. Healthy tissue barely registers the measurement — soreness usually means the gum in that area is already inflamed and infected, irritated by bacteria and buildup sitting below the gumline. In other words, it isn't the measuring that hurts; it's the early gum disease the measuring is uncovering. That tenderness is one more signal that helps us pinpoint exactly where your gums need attention. And if a spot ever does feel uncomfortable, just let us know — we can use a needle-free topical anesthetic to numb the area and keep you comfortable while we finish.

If dental visits make you tense in general, tell us.

What happens if my numbers are high?

Here's where I'll tell you how we think about it, because this is where offices differ.

A couple of 4s does not automatically mean you're getting sold a deep cleaning. Before we recommend anything, we look at the whole picture: Is there bleeding? What do the bone levels on your X-rays show? Are the numbers stable, or creeping up over time? How's your home care?

Sometimes the honest answer is "let's sharpen up your flossing on these two spots and re-measure in a few months." Sometimes the honest answer is that specific areas genuinely need scaling and root planing — cleaning below the gumline — and when that's the case, we'll show you the exact numbers and X-rays and explain why, site by site.

Every tooth is its own case. Part of your mouth can be perfectly healthy while two teeth need attention, and we treat it that way. We don't apply the most aggressive plan for the worst tooth to your whole mouth.

Frequently asked questions

How often do you do a full perio chart? Once a year for most healthy patients, usually at a hygiene visit. If we're keeping an eye on specific spots, we'll re-measure those sooner.

Can my gum numbers get better? Yes. Early inflammation (gingivitis) is fully reversible, and pockets often tighten up once plaque is under control. Bone that's already lost doesn't grow back on its own, but we can stop the loss and keep things stable for decades.

What's the difference between a regular cleaning and a deep cleaning? A regular cleaning handles everything at and above the gumline. A deep cleaning — scaling and root planing — cleans below the gumline where deeper pockets have let buildup collect. And it's only for the areas that actually need it.

Is it bad if I bleed during the measurement? It's not bad — it's information. Bleeding means inflammation, and inflammation is fixable. Nobody here is going to scold you.

My teeth feel fine. Do I really need this? Yes — feeling fine is exactly when we want to measure. Gum disease doesn't announce itself early, and healthy numbers today are the baseline that helps us spot changes later.

Wondering what your numbers are?

If it's been a while since anyone measured — or measured and actually explained it — we'd be happy to walk you through yours. Call us at 425.643.5778 or request an appointment and we'll take a look.