Porphyromonas gingivalis proteinase is responsible for the epitope development in RF-Fc region These proteinases are important virulence factors which lead to degradation of host tissue. Porphyromonas gingivalis is also a key periodonto pathogen. Thus the aim of this study is to compare the plasma pentraxin3 and p.gingivalis levels in patients with periodontitis and rheumatoid arthritis.