The aim of this study was to determine the prevalence of four selected periodontal pathogens in a large population of patients with various periodontal conditions. The study was based on the databank of a commercial laboratory that provides diagnostic testing services. The study population consisted of 10,946 patients, aged 11-85 years (mean age: 46.2 years). Subgingival plaque samples were collected and analyzed for the presence of A. actinomycetemcomitans, P. gingivalis, T. forsythensis (B. forsythus), and T. denticola using oligonucleotide probes. A total of 33,259 samples were included in the final analysis. Within this population, 97% of patients were found to harbor at least one of the four pathogens. T. forsythensis, T. denticola, and P. gingivalis were detected in 82-93% of the patients, whereas A. actinomycetemcomitans was found in only 33% of the patients. A. actinomycetemcomitans showed a skewed distribution with a higher prevalence of infected sites in patients <= 25 years (24-32% of sites). By contrast, the proportion of positive sites for the other pathogens increased with age to reach a maximum in adult populations (>= 74% of sites). The prevalence of T. forsythensis, T. denticola and P. gingivalis increased significantly with increasing probing depth. These results confirm that A. actinomycetemcomitans, P. gingivalis, T. forsythensis, and T. denticola are frequently found in populations of patients with various periodontal conditions, and that the prevalence of A. actinomycetemcomitans is higher in younger patients.
Keywords: periodontal pathogens, gingivitis, periodontitis, age