IL18 and periodontitis: Research has indicated elevated levels of tumour necrosis factor alpha (TNF‐α), interleukin 1 beta (IL‐1β), interleukin 6 (IL‐6), interleukin 8 (IL‐8), interleukin 17 (IL‐17), interleukin 18 (IL‐18), interleukin 23 (IL‐23), as well as fractalkine (CX3CL1) and its receptor (CX3CR1) in the GCF of individuals with periodontitis compared to those with a healthy periodontium [22, 23, 24, 25, 26, 27].