LL-37 as a biomarker for therapeutic response to scaling and root planing.

Background: Periodontitis is a chronic immune-inflammatory disease influenced by multiple factors. LL-37, an antimicrobial peptide, contributes to host defense, immune regulation, and tissue repair. Its subgingival expression following nonsurgical periodontal therapy remains underexplored. This study evaluates LL-37 gene expression as a potential biomarker for response to scaling and root planing (SRP). Materials and Methods: Thirty systemically healthy patients (17 males and 13 females; aged 30-50 years) with Stage II or III periodontitis were included. Clinical parameters - probing pocket depth (PPD), clinical attachment level (CAL), and modified sulcular bleeding index (mSBI) - were recorded at baseline and 1 month post-SRP. Subgingival epithelial tissue samples were collected at both time points for quantitative real-time polymerase chain reaction analysis of LL-37 gene expression. Data were statistically analyzed. Results: All clinical parameters improved significantly posttherapy. In Stage II, PPD reduced from 4.26 ± 0.53 to 3.25 ± 0.49 mm; CAL from 4.63 ± 0.32 to 3.60 ± 0.62 mm; and mSBI from 2.88 ± 0.55 to 1.45 ± 0.57. In Stage III, PPD decreased from 6.29 ± 1.24 to 4.40 ± 0.87 mm; CAL from 7.85 ± 1.11 to 5.81 ± 0.73 mm; and mSBI from 3.63 ± 0.37 to 3.22 ± 0.41 (all P < 0.05). LL-37 expression increased significantly in both groups (Stage II: 3.46 ± 0.35 to 15.1 ± 0.02 and Stage III: 3.88 ± 0.01 to 19.85 ± 0.70; P < 0.001), though correlation with clinical parameters was weak. Conclusion: SRP significantly improved clinical outcomes and upregulated LL-37 expression, supporting its potential as a biomarker for early periodontal healing.