The aim of the present study was to evaluate the association between the outcome of a chairside test measuring gingival crevicular fluid (GCF) levels of the
enzyme aspartate aminotransferase (AST) and other clinical measures of disease including probing depth, severity of
inflammation, and GCF flow before and after
therapy. We studied 91 patients with moderate to severe
periodontitis. Eight sites with probing depths between 5 mm and 8 mm and obvious signs of
inflammation were selected and designated diseased sites. Four sites with probing depth < or = 3 mm with no or minimal signs of
inflammation were selected and designated non-diseased sites in patients. Thirty healthy individuals were enrolled and four sites in each were selected and designated healthy controls. Patients were treated with scaling and
root planing and control subjects with supragingival prophylaxis. Measurements including GCF volume, gingival
inflammation, and probing depth were performed at screening baseline, 1 week later at pretreatment baseline, and at weeks 2 and 4
after treatment. AST content of GCF was measured using a chairside colorometric test. It was concluded that the outcome of the test is an effective objective measure distinguishing between diseased sites and non-diseased sites in patients and control subjects when evaluated both prior to and following application of
therapy. Use of this simple chairside test, when combined with other standard diagnostic procedures, provides an objective measurement permitting improved capacity to distinguish between diseased and non-diseased periodontal sites, and to better assess and monitor the outcome of
therapy.