A significantly higher salivary level of IL-1β was detected in the unstable periodontitis group (426 ± 59 pg/ml) than in the stable periodontitis group (247 ± 55 pg/ml; p  < 0.001) and healthy control group (204 ± 36 pg/ml; p  < 0.001) (Figure 1A); moreover, the level was significantly higher in the stable periodontitis group than healthy control group (p  < 0.05). Here, IL1B is linked to periodontitis.