Gingival crevicular fluid collagenase-2 (MMP-8) test stick for chair-side monitoring of periodontitis.

A rapid chair-side test based on the immunological detection of elevated levels of collagenase-2 (matrix metalloproteinase-8, MMP-8) in gingival crevicular fluid (GCF) was developed to identify and monitor the course and treatment of adult periodontitis. MMP-8 was determined in GCF from periodontitis (11 patients, 90 sites), gingivitis (10 patients, 58 sites) and healthy control (8 patients, 59 sites) sites (i) by a test stick incorporating monoclonal antibodies to two epitopes on MMP-8 and (ii) by measuring MMP-8 concentration by a quantitative immunofluorometric assay. Patients with adult periodontitis were treated by scaling and root planing (SRP) and received oral hygiene instructions. GCF MMP-8 testing and clinical measurements were done before and after SRP. MMP-8 GCF levels and chair-side test differentiated periodontitis from gingivitis and healthy control sites. MMP-8 GCF levels > 1 mg/l and positive chair-side test identified especially severe periodontitis sites. A positive and negative test stick result, the outcome of which was rapidly detectable in 5 mins, in GCF correlated well with MMP-8 immunofluorometric assay analysis from the collected GCF samples and the severity of periodontitis. Scaling and root planing reduced the MMP-8 levels in severe periodontitis sites with positive MMP-8 test and gingival probing pocket depth (PD) > 5 mm before treatment. The test stick result and the quantitative assay were discrepant in only 18 of the 207 sites tested, thus agreement was very good (kappa = 0.81). With a threshold of 1 mg/l MMP-8 activity the chair-side test provided a sensitivity of 0.83 and specificity of 0.96 (n = 207). The MMP-8 test can be used to differentiate periodontitis from gingivitis and healthy sites as well as to monitor treatment of periodontitis. A reduction in GCF MMP-8 levels and a change in test stick result provide a means to optimize patient control during maintenance of periodontal treatment.