Gum pocket depth: what 3mm, 5mm and 7mm really mean

What the numbers being called out mean

One to three millimetres is healthy, four to five indicates early disease, and six or more indicates established periodontitis with bone loss. The probe measures how deep the space between gum and tooth extends before the attachment stops it, and the reading is taken at six points around every tooth, which is why the examination sounds like a long recitation of numbers. A single deep reading is a local problem; deep readings throughout the mouth are a disease.

Why bleeding matters more than depth

A four-millimetre pocket that does not bleed when probed is stable and may need nothing beyond better cleaning. A three-millimetre pocket that bleeds every single time is actively inflamed and will get deeper. Bleeding on probing is the marker of current activity, and the percentage of sites that bleed is a better guide to whether your home cleaning is working than any individual depth figure. Ask for that percentage as well as the depths.

What treatment actually changes

Non-surgical debridement, cleaning the root surfaces under local anaesthesia, typically reduces a five to six millimetre pocket by one to two millimetres and stops the bleeding. Pockets deeper than six millimetres often need surgical access to be cleaned properly. There is a trade you should know about in advance: as inflammation resolves, swollen gum shrinks back, so teeth can look longer and feel more sensitive to cold. That is healing, not damage.

Cost, and the part that is on you

What determines whether it holds is the recall interval afterwards: without a professional clean every three to four months and genuinely effective interdental cleaning at home, pockets return to their previous depths within about a year. We also decline to place implants in a mouth with active periodontitis, because the bacteria that destroyed bone around teeth will do the same around an implant.

The Ones People Actually Ask.