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Nine commonly encountered subgingival species were enumerated in subgingival plaque samples from periodontally healthy, gingivitis, and adult and juvenile periodontitis subjects employing two elective and three selective media. Samples were also obtained for darkfield microscopy. Results indicated that Eikenella corrodens and Fusobacterium nucleatum were usually elevated in proportions in sites with gingivitis or destructive periodontal disease. Capnocytophaga gingivalis was associated with gingivitis whereas Capnocytophaga ochracea was found in higher proportions in subgingival plaques of subjects with juvenile periodontitis. Previous association of Actinobacillus actinomycetemcomitans with juvenile periodontitis was confirmed. Spirochetes and other motile organisms were found more frequently and in higher proportions in the three disease states and were very strongly correlated with pocket depth. Motile organisms were also positively correlated with levels of plaque and redness in contrast to cocci which showed a strong negative correlation with all clinical parameters recorded.

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The purpose of this study was to compare DNA probe analyses to cultural methods for detecting three periodontal pathogens, Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, and Bacteroides intermedius, in human subgingival plaque. Subgingival sites from patients diagnosed as either healthy or showing evidence of gingivitis or juvenile or adult Periodontitis were sampled using two paper points. The number of these pathogens from one paper point was determined using microbiologic media and speciated by biochemical tests. Results were then compared to bacterial numbers obtained from the other paper point using species‐specific DNA probes. In 60 samples from the disease group, DNA probe analysis demonstrated 100% effectiveness in detecting A. actinomycetemcomitans and B. intermedius and 91% effectiveness in detecting B. gingivalis at culture positive levels (≥103 cells). In addition, probe assays frequently identified these pathogens in samples that were culture negative. Probe analysis revealed a better correlation between presence of a pathogen and clinical evidence of disease on an individual patient basis. In contrast, most samples taken from sites of healthy individuals showed undetectable levels of all three pathogens as determined by both techniques. These results suggest that DNA probe technology is at least equivalent and often superior to cultural methods for detecting A actinomycetemcomitans, B. gingivalis, and B. intermedius in human subgingival plaque samples.

Sixty-eight strains of capnophilic fusiform Gram-negative rods from the human oral cavity were subjected to extensive physiologic characterization, tested for susceptibility to various antibiotics, and the mol-percent guanine plus cytosine of each isolate determined. The characteristics of the isolates were compared with 10 fresh and 2 stock isolates of Fusobacterium nucleatum. The isolates clearly differed from the Fusobacterium species on the basis of mol-percent guanine plus cytosine, end products, growth in a capnophilic environment and fermentation of carbohydrates. All of the gliding isolates required CO2 and formed acetate and succinate, but not H2S, indole or acetylmethylcarbinol. All fermented glucose, sucrose, maltose and mannose. The organisms may be differentiated on the basis of fermentation of additional carbohydrates, hydrolysis of polymers and reduction nitrate. Three species are proposed: Capnocytophaga ochracea, Capnocytophaga sputigena and Capnocytophaga gingivalis. Ten isolates did not fit into the proposed species.