Evidence for the early onset of gingival inflammation following short-term plaque accumulation

A study was undertaken to examine cytokine markers in gingival crevicular fluid (GCF) during the early stages of plaque accumulation.

A panel of five subjects with good oral hygiene went without brushing for 1 or 3 days, after which GCF samples were taken by placing paper strips into the gingival margins of the maxillary premolars and first molar for 30 s. GCF flow rates were determined with a Periotron instrument (Oraflow, Inc., Plainview, New York), and neutrophils (polymorphonuclear leukocytes) were determined as myeloperoxidase activity. Interleukin-1b (IL-1b) and IL-8 were eluted from the paper strips and assayed with enzyme-linked immunosorbent assay (ELISA) systems.

The plaque index rose to 2.7 +/- 0.2 (mean +/- SE) after 3 days without brushing, and the GCF flow rate increased to 146.8% of baseline. PMN and IL-8 concentrations fell but, when corrected for dilution as a result of increased GCF flow, were not statistically different from baseline. IL-1b was slightly elevated after 1 day, and increased to 223.8 +/- 54.3% (from 6.8 +/- 1.7 to 13.8 +/- 3.6 pg/30 s; p = 0.04) after 3 days of plaque accumulation. Resumption of tooth brushing led to a return of IL-1b to baseline (109.1% after 2 days of brushing). When subjects rinsed with 0.12% chlorhexidine during the 3-day no-brushing period, the increases in plaque index, GCF flow rates and IL-1b release rates did not occur.

The results indicate that IL-1b release rates increase in the GCF after 3 days of plaque accumulation, before any clinical signs of inflammation appear.