Evaluation of a chairside gingival protease test for use in periodontal diagnosis.

Collagen degradation is a major factor in the destruction of diseased periodontal tissues. Evidence from several investigations indicates that this connective tissue breakdown process may be associated with elevated levels of proteolytic activity in gingival crevicular fluid. A rapid, chairside assay for neutral proteases in biological fluids was evaluated clinically for reproducibility and an indicator of periodontal disease status. This colorimetric test is based on the use of an insoluble, covalently linked dye-collagen substrate. Enzymatic activity is monitored by estimating the production of soluble dye-labeled collagen fragments resulting from the action of sample fluid proteases on the test substrate. Gingival fluid samples were collected on three successive days from 366 interdental sites in 34 volunteers, with and without periodontal disease. Results demonstrate that the assay is reproducible with 98.6% of sampled sites remaining stable throughout the 3-day study. Furthermore, the highest percentage of elevated neutral protease activity (NPA) values and the highest NPA values were found in patients clinically diagnosed as having advanced periodontal disease.