As a single marker, IL-1β showed the best diagnostic value of these four candidates; it exhibited an AUC value of 0.88 with 90% sensitivity and 76% specificity for discriminating periodontitis subjects from healthy subjects, an AUC value of 0.80 with 83% sensitivity and 76% specificity for discriminating gingivitis subjects from healthy subjects, and an AUC value of 0.66 with 68% sensitivity and 64% specificity for discriminating periodontitis subjects from gingivitis subjects. This evidence concerns the gene IL1B and periodontitis.