Abstract: Objective: To investigate the relationship between serum leptin and periodontal indices of patients with refractory periodontitis. Methods: The study comprised of total 120 subjects (healthy controls=40, chronic periodontitis patients=40, and refractory periodontitis patients=40). The indices were detected including periodontal pocket probing depth (PD), plaque index (PLI), periodontal attachment level (AL) and the related changes in bleeding on probing (BOP). The expression levels of glycated hemoglobin (HBALC) and fasting plasma glucose (FPG) were examined by liquid chromatography. The serum leptin (LEP) expression level was determined by an enzyme-linked immunosorbent assay (ELISA). Results: The expression levels of HBALC (10.902±2.129)%, FPG (9.783±2.109) mmol/L, and LEP (1.347±0.658) μg/L in refractory periodontitis group were significantly higher than those of the chronic periodontitis group and healthy controls (HBALC (5.601±0.375), (5.142±0.319)%, FPG (5.689±0.712), (5.432±0.467) mmol/L, LEP (0.912±0.256), (0.462±0.119) μg/L (P<0.05)). There was a positive correlation between the expression level of serum leptin and the clinical periodontal indices including PD, AL, PLI and BOP (R values were 0.497, 0.534, 0.509 and 0.571 (P<0.05)). Conclusion: Expression levels of serum leptin is upregulated in patients with refractory periodontitis, which is positively correlated with PD, AL, PLI and BOP, respectively.

Key words: Leptin , Refractory periodontitis, Cinical index