Nonsurgical periodontal therapy reduced prostaglandin E2 (PGE2), interleukin-6 (IL-6), and metalloproteinase-8 (MMP-8) levels in the gingival crevicular fluid of patients with RA, which infers that nonsurgical periodontal treatment could attenuate the inflammatory process [55]. This evidence concerns the gene MMP8 and rheumatoid arthritis.