Subgingival Sulcus Research Articles

Distribution of capnocytophaga in periodontal microfloras.

Concentrations and incidence of capnocytophagae were determined in 559 samples from persons with moderate (MP), severe (SP), and localized juvenile (JP) periodontitis; persons with healthy gingiva; and children and adults participating in experimental gingivitis studies. Capnocytophagae were most frequent in four children who participated in an experimental gingivitis study. The lowest incidence and concentrations were found in subgingival floras of affected sites of persons with MP, SP, or JP.Statistically significantly (P = 0.02 to 0.05) higher proportions of capnocytophagae were found in a) sites in children with gingival index (GI) of 0 than similar sites in adults, b) sites in children with GI of 2 than GI of 0, c) supragingival and subgingival samples from healthy persons than subgingival samples from SP, d) supragingival samples from SP than subgingival samples from SP and from JP, e) supragingival samples from MP than subgingival samples from SP.These data from cross‐sectional studies indicate that the significance of capnocytophagae in the etiology of periodontal diseases has been overestimated. Their higher incidence and proportional concentrations in healthy sites and supragingival floras than in the subgingival sulcus of sites with attachment loss would indicate that they are not as competitive in the sulcus as they are on the exposed tooth surface and would argue against their being active agents of these types of destructive periodontal diseases. However, preliminary data from three persons (MP) participating in longitudinal studies show that in one of the three persons the levels of C. ochracea increased to 10 to 20% of the flora in subgingival samples in which there had been at least a 2 mm loss of attachment within three months. No capnocytophagae were isolated from similar sites in one other person, and they constituted 6% of the flora in the breakdown site in the third person.

Bacteriology of moderate (chronic) periodontitis in mature adult humans.

A total of 171 taxa was represented among 1,900 bacterial isolates from 60 samples of sites affected with moderate periodontitis in 22 mature adult humans. The composition of the subgingival sulcus flora was statistically significantly different from that of the adjacent supragingival flora and the subgingival flora of 14 people with healthy gingiva, but was not significantly different from that of sulci affected with severe periodontitis in 21 young human adults. The sulcus floras of moderate periodontitis and severe periodontitis shared many of their predominant bacterial species, but there were differences in the relative proportions of some of these species. Similar relationships were found for seven taxa of treponemes that were cultured from the samples.

Capnocytophaga: new genus of gram-negative gliding bacteria. IV. DNA base composition and sequence homology.

Isolates of Gram-negative fermentative gliding bacteria which are prominantly cultivated from the subgingival sulcus in association with periodontal lesions have been the subject of a collaborative taxonomic study. Thirty-five oral strains, isolated from various states of periodontal health and disease, were examined for DNA base composition and patterns of DNA sequence homology. The phentotypically similar organism, Bacteroides ochraceus ATCC 27872, as well as two representatives of gliding bacteria in the family Cytophagaceae, Myxococcus fulvus and Sporocytophaga myxococcoides, were included in these comparisons. Mol-percent guanine and cytosine (% G+C) was determined by thermal denaturation. Relatedness was also assessed by interspecific reassociation of DNA measured by the use of a single-strand specific S1 endonuclease. DNA purified from oral gliders, B. ochraceus ATCC27872 and S. myxococcoides contained 33–41% G+C as compared with 67% in DNA from M. fulvus. Three homology groups (designated as 25, 4 and 27) were delineated by DNA homology. Homology at the 77% level was demonstrated between B. ochraceus ATCC 27872 and the oral reference strain 25. Homology group 4 comprised four strains, all of which were isolated from cases of rapidly advancing periodontal disease. The relatively high degree of genetic divergence, observed as intergroup homology levels of less than 25%, supports the naming of three species of Capnocytophaga, C. ochracea, C. sputigena and C. gingivalis by Leadbetter et al. (1979) corresponding to DNA homology groups 25, 4 and 27, respectively.