Plaque Index
A scored clinical measure used to quantify the amount of dental plaque present on tooth surfaces, commonly used as an outcome variable in periodontal and oral hygiene research.
Full Definition
The Plaque Index (PI) is a standardized scoring system assessing the thickness or extent of dental plaque accumulation at the gingival margin of specified tooth surfaces. Multiple validated versions exist, including the Silness and Löe Plaque Index (1964) and the Turesky Modification of the Quigley-Hein Index. In dental research manuscripts, the specific index version must always be named, as different indices use different scoring scales (e.g., 0–3 vs. 0–5) and measurement criteria. Editors should verify that the scale described in the methods section is consistent with the scale used in the results tables. The term is frequently abbreviated as PI, which can conflict with other uses of that acronym in biomedical writing.
Usage
Usage note: Always specify which validated version of the Plaque Index was used. 'PI' as an abbreviation should be defined at first use, as it conflicts with other biomedical abbreviations such as 'principal investigator.'
In Context
- "Mean Plaque Index scores were significantly lower in the chlorhexidine group at the four-week follow-up (P < 0.01)." — Clinical trial results section
- "The Silness and Löe Plaque Index was used to assess oral hygiene compliance at baseline and at three months." — Materials and methods section