IL1B and gingivitis: Lastly, as the level of evidence of all the articles reviewed in undertaking this work according to the Oxford Centre for Evidence-Based Medicine Levels of evidence 2010 is IIIb and the degree of recommendation of the same is B, we can say that the evidence on using IL-1b in saliva and/or crevicular fluid as a marker of the degree of inflammation in gingivitis is conclusive.