Lysis of Collagen by Human Gingival Bacteria.∗

Summary Collagenolytic activity was demonstrated in mixed cultures of gingival bacteria from 13 of 19 individuals with chronic marginal gingivitis but from only 3 of 21 individuals with clinically normal gingivitis. This difference is statistically valid. The use of native collagen as a substrate, in the form of tendon, and the determination of the liberation of peptides containing hydroxyproline as an indication of collagenolysis are believed to make the results significant for the situation in vivo. Consequently, it is inferred that gingival bacteria may contribute to the destruction of the collagenous fibers of the periodontium seen in periodontitis.