The utility of gingival crevicular fluid matrix metalloproteinase-8 provides site-specific diagnostic value for periodontal grading

Introduction
Matrix metalloproteinase-8 (MMP-8), and its active form aMMP-8, was identified as a potential biomarker of periodontal tissue destruction. It is present at different concentrations in various oral fluids.

Material and methods
Gingival crevicular fluid (GCF) samples were collected from periodontal pockets ≥ 6 mm of 24 untreated patients using paper points and clinical parameters were recorded. 12 subjects were diagnosed with periodontitis stage III grade B, and 12 others with periodontitis stage III grade C. After thorough preparations, samples were collected following manufacturers’ instructions and analyzed using a commercially available test system for aMMP-8 evaluation (aMMP-8 Test) and Periotron 8000 together with Quantikine kits for assessment of total MMP-8 concentration (controls). Microbiological evaluation of the same pockets was carried out using real-time polymerase chain reaction.

Results
Concentrations of both total MMP-8 and aMMP-8 in GCF were higher in the case of periodontitis grade C, compared to periodontitis grade B, but reached statistical significance only in the case of total MMP-8 (77.17 ng/ml and 18.73 ng/ml respectively; p = 0.0104). Positive correlations were found between total MMP-8 and aMMP-8 levels and the prevalence of Fusobacterium nucleatum, mean probing pocket depth of all pockets, % of pockets ≥ 6 mm, as well as probing pocket depth of pocket from which GCF samples were collected.

Conclusions
GCF concentration levels of both total MMP-8 and aMMP-8 correlated with severity of periodontal destruction, whereas total MMP-8 appeared to be a preferable method for differentiation of periodontal grading. However, the aMMP-8 Test was easier and more convenient to handle.