After excluding the keywords “rheumatoid arthritis” and “arthritis,” the top 10 keywords identified were P. gingivalis PD inflammation expression peptidylarginine deiminase (PAD) gut microbiota gingival crevicular fluid (GCF) antibody Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) and T cells (Figure 6). The gene discussed is PADI4; the disease is arthritic joint disease.