CXCL8 and chronic periodontitis: In chronic periodontitis, the pro-inflammatory factors involved in bone resorption include IL-6, IL-8 and TNF-α.42 In the present study, the treatment groups showed a slight increase these cytokines at the 6-month follow-up, which is in agreement with Niazi et al,30 who found similar changes in cytokine levels at follow-up.