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

Background: 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. Methods: 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. Results: 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 (κ = 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). Conclusion: 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.