The oral microbiota change dramatically with each part of the oral cavity, even within the same mouth. Nevertheless, the microbiota associated with peri-implantitis and periodontitis have been considered the same. To improve our knowledge of the different communities of complex oral microbiota, we compared the microbial features between peri-implantitis and periodontitis in 20 patients with both diseases. Although the clinical symptoms of peri-implantitis were similar to those of periodontitis, the core microbiota of the diseases differed. Correlation analysis revealed the specific microbial co-occurrence patterns and found some of the species were associated with the clinical parameters in a disease-specific manner. The proportion of Prevotella nigrescens was significantly higher in peri-implantitis than in periodontitis, while the proportions of Peptostreptococcaceae sp. and Desulfomicrobium orale were significantly higher in periodontitis than in peri-implantitis. The severity of the peri-implantitis was also species-associated, including with an uncultured Treponema sp. that correlated to 4 clinical parameters. These results indicate that peri-implantitis and periodontitis are both polymicrobial infections with different causative pathogens. Our study provides a framework for the ecologically different bacterial communities between peri-implantitis and periodontitis, and it will be useful for further studies to understand the complex microbiota and pathogenic mechanisms of oral polymicrobial diseases.

Background: The aim of the present study was to identify Treponema socranskii in addition to Treponema denticola and Porphyromonas gingivalis by polymerase chain reaction (PCR), and to clarify the relationship between the presence of these microorganisms and the severity of clinical periodontal parameters.Methods: Saliva and subgingival plaque collected from 123 subjects (38 aggressive periodontitis patients, 65 chronic periodontitis patients, 20 healthy patients) were subjected to PCR to detect the aforementioned 3 microorganisms.Results: Detection frequencies of T. socranskii, T. denticola, and P. gingivalis in plaque samples from aggressive periodontitis patients (71.1%, 73.7%, 84.2%, respectively) and chronic periodontitis patients (89.2%, 93.8%, 95.3%) were much higher than those from healthy subjects (30%, 5.0%, 10.0%). In aggressive and chronic periodontitis patients, these 3 species of bacteria were detected frequently at sites that showed deep periodontal pockets and severe attachment loss. The percentage of these bacteria‐positive sites increased as the gingival index score of chronic periodontitis patients increased. T. socranskii was frequently detected together with T. denticola or P. gingivalis at the same sites, and coexistence of these microorganisms was frequently observed in deep periodontal pockets of aggressive periodontitis patients.Conclusions: T. socranskii, T. denticola, and P. gingivalis were frequently detected in periodontitis patients by PCR. The prevalence of these 3 microorganisms was correlated with various clinical parameters. Taken together, our findings suggest that T. socranskii, T. denticola, and P. gingivalis are associated with the severity of periodontal tissue destruction. J Periodontol 2001;72:1354‐1363.

The quantity of periodontopathic bacteria in plaque samples is an important determinant for understanding the etiologic role of bacteria. The real‐time PCR method was used to detect and quantify periodontopathic bacteria, such as Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Porphyromonas gingivalis, Treponema denticola, and Treponema socranskii, in saliva and subgingival plaque samples. There was good agreement between the results of conventional PCR and real‐time PCR methods. Using the LightCycler™ system we were able to determine the amount of periodontopathic bacteria within an hour. The real‐time PCR method was linear for samples containing from 10³ to more than 10⁸ cells (r²=0.999). The application of the real‐time PCR method should be useful in the rapid detection and quantification of periodontopathic bacteria in clinical samples.

Analysis of microbiota associated with peri-implantitis using 16S rRNA gene clone library