Comparison of the microbiota of supra- and subgingival plaque in health and periodontitis

Background, aims: The purpose of the present investigation was to compare t he microbial composition of supra and subgingival plaque in 22 periodontall y healthy (mean age 32 +/- 16 years) and 23 adult periodontitis subjects (m ean age 51 +/- 14 years). Methods: A total of 2358 supra and separately subgingival plaque samples we re collected from the mesial aspect of all teeth excluding 3rd molars in ea ch subject. Samples were examined for the presence and levels of 40 bacteri al taxa using whole genomic DNA probes and checkerboard DNA-DNA hybridizati on. Clinical assessments including dichotomous measures of gingival redness , bleeding on probing, plaque accumulation and suppuration, as well as dupl icate measures of pocket depth and attachment level, were made at 6 sites p er tooth, Mean counts (x10(5)), % DNA probe count and % sites colonized for each species were determined separately for supra and subgingival samples in each subject and then averaged across subjects in the 2 clinical groups. Significance of differences between healthy and periodontitis subjects was determined using the Mann-Whitney test and adjusted for multiple compariso ns. Results: Mean total DNA probe counts (x10(5), +/-SEM) for healthy and perio dontitis subjects in supragingival plaque were 72.1 +/- 11 and 132 +/- 17.5 , respectively (p<0.01), and in subgingival plaque 22.1 +/- 6.6 and 100.3 /- 18.4, (p<0.001). Porphyromonas gingivalis, Bacteroides forsythus and Tre ponema denticola could be detected in supragingival plaque samples of both healthy and periodontitis subjects. Actinomyces species were the dominant t axa in both supra- and subgingival plaque from healthy and periodontitis su bjects. 4 Actinomyces species accounted for 63.2% of supragingival and 47.2 % of subgingival plaque in healthy subjects and 48.1% and 37.8% in periodon titis subjects respectively. Increased proportions of P. gingivalis, B. for sythus, and species of Prevotella, Fusobacterium, Campylobacter and Trepone ma were detected subgingivally in the periodontitis subjects. P. gingivalis , B, forsythus and T. denticola were significantly more prevalent in both s upra- and subgingival plaque samples from periodontitis subjects. Conclusions: The main differences between supra and subgingival plaque as w ell as between health and disease were in the proportions and to some exten t levels of Actinomyces, "orange" and "red" complex species.