Although periodontitis is a chronic inflammation, and the expression of TLR2 and TLR4 is aberrant in the GF (24, 35), the effect of the activation of these specific TLRs on osteoclastogenesis and osteogenesis is only evaluated after short (<60 h) stimulation (36–40), and scarcely on cells derived from human periodontal tissues (34, 41–43). The gene discussed is TLR4; the disease is periodontitis.