[Relationship of serum and gingival crevicular fluid antibody levels with the amount of subgingival homologous bacterium in patients with periodontal disease].

39 patients were selected in this study, including 12 patients with rapidly progressive periodontitis (RPP), 17 with adult periodontitis (AP) and 10 with marginal gingivitis (MG). The levels of antibody to Porphyromonas gingivalis (Pg) in serum (Sr) and in gingival crevicular fluid (GCF) from their 156 teeth were measured by ELISA. The Pg in subgingival plaque was detected by indirect immunofluorescence technique. Data showed different GCF/Sr ratio of anti--Pg antibody level between periodontitis patients (lower than 1) and MG patients (greater than 1). The amount of subgingival Pg was negatively correlated with clinical periodontal parameters, i.e, probing depth, attachment loss, plaque index and bleeding index. It was suggested that low GCF/Sr ratio of antibody level plus high counts of homologous bacterium might be used as an indicator of periodontal disease activity.