Terminal RFLP (T-RFLP) analysis was used to investigate changes in the oral microbiota in saliva and subgingival plaque samples from one patient with aggressive periodontitis (subject A) and two patients with chronic periodontitis (subjects B and C) before and 3 months after periodontal treatment. Substantial changes in the T-RFLP patterns of subgingival plaque samples of subjects B and C were noted after 3 months of improved oral hygiene and full-mouth supra-and subgingival scaling and root planing. However, there was little change in the subgingival microbiota of subject A. Although the proportions of terminal restriction fragments (T-RFs) larger than 1000 bp were notable in the T-RFLP patterns generated after digestion with HhaI of the samples from two subjects before treatment (subject B, 35 . 5 %; subject C, 29 . 6 %), the proportions of these T-RFs were significantly reduced or not detected after treatment (subject B, none; subject C, 4 . 1 %). Real-time PCR showed a significant change in the proportions of target bacteria in subgingival plaque samples of subject B. After 3 months, the Porphyromonas gingivalis population was markedly reduced (3 . 1 3 10 À3 %), whereas the proportion of Porphyromonas gingivalis before treatment was 7 . 6 %. The proportions of Tannerella forsythensis, Treponema denticola and Treponema socranskii were also markedly diminished after treatment. Similarly, the proportion of the T-RF presumed to represent Porphyromonas gingivalis was 5 . 9 % and became undetectable after 3 months. Analysis of 16S rRNA gene clone libraries from subgingival plaque samples of subject B before and after treatment showed a notable change in the subgingival microbiota. These results were in agreement with the T-RFLP analysis data and showed that the T-RFs larger than 1000 bp represent Peptostreptococcus species. Our results indicate that T-RFLP analysis is useful for evaluation of the effects of medical treatment of periodontitis.

P. gingivalis, A. actinomycetemcomitans and T. forsythensis can localize in diseased gingival tissue and may be involved in periodontal tissue destruction. Serotype c is the predominant serotype of A. actinomycetemcomitans in Japanese LAgP patients.

The aim of the present study was to clarify the relationship between the relative/absolute numbers of periodontal bacteria and different types of periodontitis. Fifteen patients with localized aggressive periodontitis (LAgP), 25 patients with generalized aggressive periodontitis (GAgP) and 28 patients with chronic periodontitis (CP) were included in this study. Saliva and subgingival plaque samples were collected from all subjects for microbiological analysis. The prevalence and proportions of Actinobacillus actinomycetemcomitans, Tannerella forsythensis, Porphyromonas gingivalis and Treponema denticola were determined by conventional PCR and real-time PCR. The prevalence of A. actinomycetemcomitans in saliva was significantly higher in LAgP patients (46.7%) and GAgP patients (40.0%) than that in CP patients (14.3%). The mean proportion of A. actinomycetemcomitans in LAgP patients (4.42%) was significantly higher than that in GAgP patients (0.59%) and CP patients (0.37%) in saliva. In subgingival plaque, LAgP patients showed a significantly higher mean proportion of T. forsythensis (19.8%) than CP patients (7.45%). In conclusion, A. actinomycetemcomitans was the more predominant periodontopathic bacteria in LAgP than in GAgP and CP. The increased proportion of T. forsythensis might relate to LAgP, in addition to A. actinomycetemcomitans. These results indicate that real-time PCR analysis is useful for the evaluation of the bacterial profiles in different types of periodontitis.