Several mechanisms regulate bone resorption in periodontitis, such as macrophages derived from monocytes, TNF-α, PGE2, and IL-1, with the activation of T, B, CD4+, and CD8+ cells, which consequently destroy the gingival microflora and accelerate bone loss; periodontal ligament cells and gingival fibroblasts participate in this [85]. Here, TNF is linked to periodontitis.