A positive and statistically significant association between CRP in serum and GCF was observed in all groups (p = 0.00), with a Spearman’s rank correlation coefficient (rho) of 0.87, 0.63, 0.88, and 0.70 in healthy individuals, gingivitis, periodontitis, and the total sample of volunteers, respectively (Table 3). This evidence concerns the gene CRP and periodontitis.