First, its cross-sectional design does not enable an analysis of NGAL in the pathogenesis of periodontal disease, which requires future randomized case-control studies investigating the cut-off values of serum and salivary NGAL levels in periodontally healthy and compromised patients, and employing interventional approaches (comparing NGAL levels before and after non-surgical periodontal therapy). Here, LCN2 is linked to periodontal disorder.