Associationsbetween periodontal disease (PD) and other diseases, including rheumatoid arthritis (RA), respiratory disease, and chronic kidney disease, have been reported. Patients with moderate to severe periodontitis have a high risk of suffering from RA and vice versa. This bidirectional relationship could be due to genetic (HLA-DR), dysregulation of the inflammatory response, and the role of Porphyromonas gingivalis(P. gingivalis), which stimulates anti-cyclic citrullinated peptide antibodiesvia citrullination. This review aims to identify associated factors that contribute to RA and PD relationship and to explore the effects of disease-modifying anti-rheumatic drugs (DMARDs) on PD. A literature search was performed using PubMed and Google Scholar to identify related articles published from the year 1990 to 2020 within the research interest using keyword combinations. Thirty-one articles thatfit the research interest and address the research questions for both objectives were selected. As a result, the associated factors for RA and PD relationship, including genetic predisposition, immunoregulatory imbalance, and the role of P. gingivalisin the citrullination process as a risk factor of RA. Significant improvement was found in periodontal parameters in RA patients treated with biologic and synthetic DMARDs. This review reported common factors contributing to the RA and PD relationship and the benefits of DMARDs on periodontitis.