Correlations between gingival crevicular fluid enzymes and the subgingival microflora

Bacteroides gingivalis is a Gram-negative micro-organism implicated in the pathogenesis of adult periodontitis and producing relatively large amounts of specific enzymes. In the present study, subgingival samples taken from adults with moderate periodontitis were examined for the presence and relative amounts of enzymatic activity toward certain substrates. Enzyme levels were then correlated with clinical periodontal indices and microbiological analysis of subgingival plaque, including darkfield microscopy for bacterial morphotypes and immunofluorescence microscopy for B. gingivalis and Bacteroides intermedius. The results of this study indicate a significant positive correlation between levels of enzyme capable of degrading N-benzoyl-D,L-arginine-beta-naphthylamide hydrochloride, and subgingival B. gingivalis (r = 0.55). There was a much lower correlation coefficient between this enzyme activity and subgingival B. intermedius (r = 0.26). Statistically significant (p less than 0.01) positive correlations were also demonstrated between total bacterial cell counts and levels of enzymatic activity against N-benzoyl-D,L-arginine-beta-naphthylamide hydrochloride (r = 0.76), N-carbobenzoxy-glycyl-glycyl-L-arginine-beta-naphthylamide hydrochloride (r = 0.72), and glycyl-L-proline-4-methoxy-beta-naphthylamide hydrochloride (r = 0.72), and glycyl-L-proline-4-methoxy-beta-naphthylamide hydrochloride (r = 0.69). There were significant differences in the levels of these three enzymatic activities between sites exhibiting various degrees of clinical severity of gingival inflammation and harboring various proportions of B. gingivalis. The data from this study indicate that measurement of specific enzymatic activities in subgingival samples can be useful in the diagnosis of B. gingivalis-associated periodontitis.