What periodontitis is, in plain words
Periodontitis, still sometimes called pyorrhoea, is a long-running inflammation of the tissues that hold each tooth in its socket. It starts with the bacterial film called plaque at the gum line. In many mouths that film causes gingivitis, gums that are red and bleed easily, and goes no further. In a susceptible person the inflammation reaches deeper, and the fibres and bone that anchor the tooth are slowly lost. The gap this opens between the gum and the root is the pocket that the probe measures.
Susceptibility is partly inherited: the genetic share of the risk is estimated at up to half. The rest is acquired, and much of it can be changed: smoking, diabetes that is undiagnosed or not well controlled, and obesity all add to it [1]. That is why two people with the same amount of plaque can have very different gums, and why your chart, not the look of your gums, decides what you need.
Severe periodontitis is common. It affects about 11% of adults worldwide, and new cases are most frequent at around the age of 38 [5]. Your thirties are a sensible time to have your gums properly charted, even if nothing hurts and your teeth feel firm.
The reading is the distance from the gum's edge to where the probe stops, shown by the bracket beside each probe. Healthy gums read 1 to 3 mm and do not bleed; the aim of treatment is no pocket deeper than 4 mm that bleeds and none of 6 mm or more.
Diagram page and reuse terms: What the probe measures
Sources and measurements
- Healthy gum anatomy: the gum edge sits about 1 mm above the enamel's edge and healthy gums probe 1 to 3 mm (Woelfel's Dental Anatomy). Under a groove about 0.7 mm deep lie about 1 mm of attaching epithelium and 1 mm of fibres above the bone, Gargiulo's autopsy means, which vary from person to person. DOI 1, What the probe measures
- Gum thickness: at the lower front teeth the gum averaged 0.71 mm thick, and healthy pockets read 1.79 mm on average, in 187 people with healthy gums. DOI 2, What the probe measures
- The probe: commercial probe tips measured 0.28 to 0.70 mm across, and a light force of about 0.25 N is used; at higher forces healthy gums bleed more often. DOI 3, What the probe measures
- Where the probe stops in health: at 22 sites on front teeth, the probe tip stopped inside the junctional epithelium, on average 0.25 mm short of its end. DOI 4, What the probe measures
- Where the probe stops in a pocket: in untreated pockets the tip went 0.29 mm (Magnusson and Listgarten 1980) and 0.45 mm (Fowler 1982) past the epithelium into inflamed tissue, well short of the bone; after treatment it stopped inside the epithelium. DOI 5, What the probe measures
- Bone around lower central incisors: in CBCT scans of 50 women without gum disease, the bone crest lay about 2.2 to 2.8 mm below the enamel's edge, and the bone on the lip side was thin, about 0.5 to 0.75 mm including the ligament, along most of the root. DOI 6, What the probe measures
- The European guideline (EFP S3): the aim is no pocket deeper than 4 mm that bleeds and none of 6 mm or more; sites are re-assessed after healing; hand or powered instruments, or both; supportive care every 3 to at most 12 months. DOI 7, What the probe measures
- The tooth: a lower central incisor in section, crown 9.5 mm and root 12.5 mm (Wheeler's Dental Anatomy, Table 7.1), with the lip side on the left. Pockets and openings are drawn slightly open so they can be seen; no number on the drawing is a measurement of one person.