A gum check in a few minutes: what the PSR index shows

Gums can be diseased for years without any pain. PSR is a quick gum screening: the periodontist checks each of the six areas of the mouth with a thin probe and, within a few minutes, sees whether there is inflammation, calculus or periodontal pockets. At Houston we do this test at the consultation and before every professional hygiene visit, at no extra charge.

Why gums are checked when nothing hurts

Gum inflammation rarely hurts. The first signal is blood on the toothbrush or floss, and it is the one people most often dismiss: “weak gums”, “I pressed too hard”. Meanwhile the inflammation can slowly spread from the gums to the ligaments and bone around the tooth. By the time a tooth starts to wobble, part of the bone is already lost, and it is hard to restore it fully.

This is a common problem. According to the Global Burden of Disease 2021 study, more than a billion people worldwide have severe periodontitis — roughly one adult in eight. Most of them find out late, because nothing bothers them in the early stages.

That is why gums are checked the same way teeth are checked for decay: without complaints, during a routine examination. There is a quick standardised test for this — the PSR index.

What the PSR index is

PSR (Periodontal Screening and Recording) is a periodontal screening, a quick check of the gums. It was introduced in 1992 by the American Dental Association (ADA) and the American Academy of Periodontology (AAP), based on the WHO CPITN index. In the United Kingdom the same approach is called the BPE (Basic Periodontal Examination), and the British Society of Periodontology recommends doing it at every routine examination.

The test uses a special WHO probe. Its tip ends in a ball 0.5 mm in diameter so as not to injure the gums, and a coloured band is marked 3.5–5.5 mm from the tip. How far the band disappears under the gum shows the depth of the gum crevice.

The result is recorded as six numbers, one for each area of the mouth. The dentist and the patient immediately see where the gums are healthy and where attention is needed.

How the check is done

The mouth is divided into six areas (sextants): three in the upper jaw and three in the lower — right side, front and left side. The periodontist walks the probe along every tooth and notes three things: whether the gum bleeds, whether there is calculus or an overhanging filling margin, and how deep the probe goes.

The pressure is light — about 20–25 grams, exactly the force the protocol specifies. No anaesthetic is needed. If the gums are inflamed, a little blood may appear; that is one of the signs the dentist is looking for.

The whole check takes a few minutes. The worst finding in each area is recorded, so the six numbers give a complete picture of the gums.

What codes 0 to 4 mean

• 0 — healthy gums: the coloured band is fully visible, with no bleeding, calculus or overhanging filling margins.
• 1 — the gum bleeds after probing, but there is no calculus and the crevice is shallow. This is a sign of gingivitis.
• 2 — there is calculus, or a filling or crown margin that overhangs and traps plaque. The band is still fully visible.
• 3 — the band is partly hidden: a periodontal pocket of 3.5–5.5 mm. The inflammation has already reached the tissues that hold the tooth.
• 4 — the band disappears completely: the pocket is deeper than 5.5 mm. This is a sign of advanced periodontitis.
• * — an asterisk next to the code: an exposed root, involvement of the area between the roots (furcation), tooth mobility or other changes the dentist takes into account separately.

Codes 0–2 mean the process is still reversible: professional hygiene and proper home care deal with it. Codes 3 and 4 mean that area needs a detailed examination.

What we do after the test

The PSR result turns straight into specific steps:

• Code 0. We choose your home care and repeat the check at the next examination.
• Code 1. We show where the gums are inflamed, teach you to clean between the teeth and book a professional hygiene visit.
• Code 2. Professional hygiene with calculus removal; an overhanging filling or crown is corrected.
• Code 3. We make a detailed pocket chart of that area and take an X-ray if needed.
• Code 4 or an asterisk. A full periodontal chart — measurements at six points around every tooth — and an X-ray examination. After that the periodontist draws up a treatment plan.

This sequence follows the British Society of Periodontology guidance: codes 3 and 4 call for X-rays, and a code 4 in any area is a reason to chart all the teeth.

What PSR does not show

PSR is a screening. It quickly answers the question “is there a problem, and where”, while the final diagnosis of periodontitis is made after a full examination: a pocket chart, an assessment of tooth mobility and X-rays.

The test is not done around implants — the tissues are built differently there and have their own examination rules. PSR does not replace an X-ray either: the probe assesses the gums and pockets, while the X-ray shows the bone.

The result reflects your condition today. If you smoke, have diabetes, are pregnant or take medicines that affect the gums, tell your dentist: it determines how often the check should be repeated.

PSR at Houston: who does it and what it costs

The check is done by the clinic's periodontist, deputy head doctor Anna Vasylenko, with 22 years in practice. We do PSR at the consultation and before every professional hygiene visit. There is no separate fee for the test: a specialist consultation costs UAH 690, professional hygiene from UAH 2,300.

We record the result in your chart, so at the next visit we can see the trend: whether the gums have settled after hygiene and whether any new problem areas have appeared. Why healthy gums matter beyond your teeth is explained in our article on how gum inflammation is linked to your overall health.

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Sources

• British Society of Periodontology. Basic Periodontal Examination (BPE), 2019. www.bsperio.org.uk/assets/downloads/BSP_BPE_Guidelines_2019.pdf
• Nascimento G.G. et al. Global, regional and national burden of severe periodontitis, 1990–2021 (GBD 2021). Journal of Periodontal Research, 2024. pubmed.ncbi.nlm.nih.gov/39192495/

Frequently asked questions

Anna Vasylenko

Deputy head doctor · periodontist

22 years in practice (graduated from Dnipro Medical University in 1999). An evidence-based approach to hygiene and to treating the gums and periodontitis.

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