Exploring the relationship between Porphyromonas gingivalis in periodontitis and rheumatoid arthritis severity: a cross-sectional pilot study

Objectives This study aimed to explore the relationship between site-specific Porphyromonas gingivalis ( P. gingivalis ) levels, PSR-defined periodontitis status, and the clinical severity of rheumatoid arthritis (RA). Methods In total, 28 patients with RA were included. The erythrocyte sedimentation rate (ESR) was quantified using the Wintrobe method. Serum levels of C-reactive protein (CRP) and rheumatoid factor (RF) were measured via turbidimetric assay, while anti-cyclic citrullinated peptide (anti-CCP) antibodies were determined by enzyme-linked immunosorbent assay (ELISA). Periodontal diagnosis was performed using a simplified Periodontal Screening and Recording (PSR), assessing bleeding on probing (BOP) and probing depth (PD), detection and quantification of site-specific P. gingivalis were carried out using qPCR. Results Bivariate analysis revealed a statistically significant difference between groups for ESR, which was higher in the PSR-based periodontitis group than in the non-periodontitis group(26.5 mm/h vs. 21 mm/h, p = 0.04). Additionally, positive correlations were observed between site-specific P. gingivalis levels and both joint erosion(JE) (rho = 0.45; p = 0.02), and radiological grade (RG) (rho = 0.42; p = 0.04). Conclusions This small pilot study observed exploratory trends suggesting that patients with co-occurring rheumatoid arthritis and PSR-defined periodontitis harboring site-specific P orphyromonas gingivalis may present with elevated disease activity. However, sample size constraints and non-significant associations following multiplicity corrections preclude confirming direct links with joint degradation, requiring validation in prospective studies using full-mouth diagnostic staging and representative microbiological sampling.