MARIA ALEXANDRA MARTU, SORINA MIHAELA SOLOMON, IRINA GEORGETA SUFARU, IGOR JELIHOVSCHI, SILVIA MARTU, ELENA REZUS, AMELIA ELENA SURDU, ROXANA MADALINA ONEA, GINA PAUNITA GRECU, LILIANA FOIA STUDY ON THE PREVALENCE OF PERIODONTOPATHOGENIC BACTERIA IN SERUM AND SUBGINGIVAL BACTERIAL PLAQUE IN PATIENTS WITH RHEUMATOID ARTHRITIS The purpose of this study was to detect bacterial periodontal DNA from subgingival dental plaque and serum in patients affected by rheumatoid arthritis and periodontitis. The study group included 19 patients with periodontitis and refractory rheumatoid arthritis. The patients were clinically examined and diagnosed and the bacterial DNA was detected in the subgingival bacterial plate and serum by PCR. Severe chronic periodontitis was the most commonly diagnosed (42.2%). The DNA of periodontopathogenic bacteria was detected 100% in subgingival plate samples, and in serum samples it was identified in 84.2% of cases. The most commonly found species in subgingival plate samples were P. intermedia (100%), T. denticola (84.2%) and P. gingivalis (78.9%). In serum samples, the most frequently detected species were P. intermedia (89.4% and 73.6% respectively) and P. gingivalis (57.8% and 42.1%, respectively). A. actinomycetemcomitans and P. gingivalis did not show statistically significant differences between samples. This finding suggests that it could be an association because the same bacteria species detected in the serum were present in bacterial plaque samples. Patients with rheumatoid arthritis contain levels of oral pathogens in the serum and subgingival plaque that are common to red complex organisms, namely Porphyromonas gingivalis, Tannerella forsythia and Prevotella intermedia.