On the other hand, a positive correlation was observed between salivary IL-6 and PI (rs = 0.675; p < 0.05) in G3 (OSA), and BOP (%) and PI in G4 (P-OSA), which may be explained by the existence of a biofilm in these individuals that increases IL-6 levels as well as the risk of inducing a local inflammatory response; thus, IL-6 could serve as an early salivary biomarker of periodontitis associated to OSA. The gene discussed is IL6; the disease is obstructive sleep apnea syndrome.