Early detection with the PSI – Periodontal Screening Index

Since 2004 the German statutory health insurers have covered a screening examination for periodontal disease every two years. The PSI, the Periodontal Screening Index, can be recorded during an ordinary dental check-up as part of the recall.

Early detection with the PSI: the Periodontal Screening Index makes it possible to gain a reliable overview of the state of the periodontium and to spot early forms of periodontal disease. Regular and complete examination of the periodontium matters because it allows treatment to begin while the disease is still in its early stages. The sooner periodontal disease is found, the better and more successfully it can be treated.

During the examination and history-taking, the dentist asks not only about acute symptoms but also about existing conditions (diabetes or high blood pressure, for example), medication and habits. Where periodontal disease is present, patients are often asked whether family members have had periodontitis as well. If periodontitis occurs despite conscientious oral hygiene, a genetic test can show whether there is a familial predisposition. The test analyses the genetic information of the bacteria responsible for triggering periodontitis. Patients with a genetic predisposition carry a considerably higher risk of developing the disease.

Marker bacteria diagnostics using DNA tests

The genetic information of the bacterial strain is individual to each patient, so the pathogens can be identified through DNA analysis. Secretion from the periodontal pocket or from plaque is enough for this. A sterile paper point is placed for about 15 to 20 seconds into several pockets that are as dry as possible and show signs of inflammation. The DNA is isolated from the secretion or plaque sample; the processing and decoding of the bacteria takes place in a laboratory. Detecting the gene is sufficient to identify the marker bacteria.

The Periodontal Screening Index / PSI

The PSI examination is not elaborate, it is painless and takes only a few minutes. The upper and lower jaw are divided into six sextants, and various measuring points are defined.

Using a blunt dental probe with a millimetre scale, guided gently between tooth and gum, every tooth is probed all the way round. The dentist checks how deep the pockets immediately around the tooth are and how readily the gum bleeds. A table then shows how far the periodontal disease has advanced. Patient-related factors carry particular weight here: the total number of residual pockets, periodontal bone loss, the patient's age, tooth loss, smoking, systemic and genetic factors, medication and the state of oral hygiene.

The findings are graded into five codes.

Code 0: healthy gums with nothing abnormal.
Code 1: bleeding on contact indicates gingival inflammation.
Code 2: edges and margins of fillings as well as roughness from calculus or plaque are found.
Codes 1 and 2 are the first signs of gingivitis.

Code 3: shallow pocket; the probe can be inserted a few millimetres into the gap between tooth and gum. This points to moderate periodontal disease. Treatment is required.

Code 4: deep pocket; the probe can be inserted far into the gap between tooth and gum. Severe periodontal disease – periodontitis – is present. Treatment is required, and detailed periodontal diagnostics must be carried out.

Once the Periodontal Screening Index has been recorded, the dentist can judge the individual risk of disease and draw up a treatment plan tailored to the patient.

Regular screening is necessary. The Periodontal Screening Index offers a quick and simple way of identifying whether a patient needs periodontal treatment.

Measuring the sulcus bleeding index (SBI) and the papilla bleeding index (PBI) assesses how readily the gum bleeds and whether bleeding occurs in the area of the papilla. Further radiographic findings are obtained where needed. Any damage to the bone, or recession of the jawbone, can be shown on X-rays.

Three-dimensional layered images from digital volume tomography can also show how periodontal pockets have formed.

Regular screening is necessary so that a need for periodontal treatment is identified as early as possible.

Bleeding on probing / BoP

Bleeding on probing is an important clinical parameter. BoP is a fairly reliable sign of gingival inflammation and supports the assessment of inflammation in a periodontal pocket.

BoP positive: severe inflammation can lead to heavier bleeding.

BoP negative: healthy gums do not bleed on probing. The absence of bleeding on probing is judged, with high probability, to be a stable situation. In smokers, bleeding on probing can fail to appear even though inflammatory processes are present at the base of the pocket.

Probing and its finding – BoP positive or negative – matters both in primary diagnostics and in follow-up after periodontal therapy has been completed. At recall, bleeding on probing can be used to assess oral hygiene and as an indicator of how effective it is.

The API, the approximal plaque index, is also important for monitoring.

It assesses how efficient oral hygiene is. Cleaning the smooth surfaces of the teeth is less demanding than cleaning between them. A probe is therefore used – with or without staining the plaque – to check whether deposits can be scraped out of the interdental space. As with BoP the result is recorded as yes or no, and it can be expressed as a percentage from the positive findings and the total number. A value below 20 per cent indicates good oral hygiene.