TLR4 and periodontitis: Compared with those released from either T. denticola or T. forsythia, BEVs released from P. gingivalis induced stronger TLR2- and TLR4-specific responses and more moderate responses in cells expressing NOD2, NOD1, TLR8, TLR7, and TLR4, confirming the dominant roles of P. gingivalis and related BEVs in the pathogenesis of periodontitis.