TNF and periodontitis: The “strict” periodontitis subgroup produced median levels of SOST (140.00 pg), WNT-5a (2.4 pg) and TNF-α (44.7 pg) compared with the “strict” healthy group who exhibited levels of SOST (78.9 pg), WNT-5a (1.29 pg) and TNF-α (27.3 pg).