In addition to IL-1β and TNF-α, receptor activator of nuclear factor kappa-B ligand (RANKL) also plays a significant role in bone physiology and periodontal bone resorption.27, 28During the early stages of periodontitis induction in the ligature model (1 and 3 days after ligature implantation), there was a significant increase in the mRNA expression of IL-1β and TNF-α. The gene discussed is TNF; the disease is periodontitis.