Abstract. The effect of serum inhibitors on determinations of collagenolytic activity in culture fluids of healthy (G.I.=0) and mildly inflamed (G.I.=1) gingival tissue was studied. Gingival biopsies obtained at the beginning of the experimental gingivitis period (G.I.=0) and after approximately three weeks of no oral hygiene (G.I.=1) were subjected to tissue culture procedures previously utilized for the determination of collagenolytic activity. Inhibition of collagenase activity was evaluated by denaturing scrum inhibitors retained in culture fluid with sodium thiocyanate or by adding culture fluid from normal and inflamed tissues to a partially purified collagenase preparation. A decrease in collagenolytic activity was consistently demonstrable in untreated culture fluids of gingival tissue manifesting G.I.=1 as compared lo those exhibiting G.I.=0. When enzyme containing culture fluids were treated with NaSCN. however, no essential difference was detected. While culture fluids from healthy gingiva showed no inhibition of partially purified collagenase, culture fluids from tissues manifesting mild inflammation inhibited enzyme activity by approximately 60 %. A number of cell types associated with the periodontium have the ability to produce a specific collagenase. The results of this investigation suggest, however, that in vitro determinations of collagenolytic activity in culture fluids of normal and inflamed tissues may be influenced by specific scrum inhibitors.

Complete (CFA) and incomplete (IFA) Freund's adjuvant was injected into the periodontium of sensitized marmoset, capuchin and rhesus monkeys. All animals developed a proliferative granulomatous reaction at the injection sites. There were, however, species specific differences in the degree of destruction associated with the CFA injection. The marmosets and capuchins developed a destructive periodontitis. In the rhesus monkey, the lesion was both bone destructive and bone inductive. Tubercles containing typical Langhan's type giant cells, but without central necrosis, were only produced by the rhesus monkey. Granulation tissue with no necrosis was produced by the marmoset and capuchin monkeys. While there was some degree of periodontal destruction in all CFA injected animals, it was most severe in the marmoset followed in descending order by the capuchin and by the rhesus. The injection of IFA into the periodontium of the same animals resulted in the formation of nondestructive highly proliferative granulation tissue.