The study found that smokers with chronic gum disease have lower levels of the antimicrobial peptide LL‑37 in their gum fluid compared to non‑smokers, and that a standard deep‑cleaning treatment lowered LL‑37 in non‑smokers but not in smokers. In healthy gums, smoking didn’t change LL‑37 levels. This suggests smoking hampers the natural immune response in diseased gums and may blunt the benefits of routine periodontal cleaning.

LL-37 contributes to maintaining the balance between health and disease. Smoking is a risk factor for periodontitis that impairs neutrophil functions. The aim of the present study was to comparatively evaluate gingival crevicular fluid (GCF) LL-37 levels in smoker and non-smoker chronic periodontitis (CP) patients and controls, as well as the effect of non-surgical periodontal treatment on GCF LL-37 levels. Thirty-one CP patients (16 smokers, 15 non-smokers) and thirty-one controls (16 smokers, 15 non-smokers) were included in the study. CP patients received non-surgical treatment. GCF LL-37 levels and periodontal parameters were assessed at baseline, 1 and 3 months after completion of non-surgical periodontal treatment. GCF LL-37 levels were analyzed by ELISA. No significant difference was observed in GCF LL-37 levels between smoker and non-smoker controls (p>0.05). Smoker CP group had significantly lower GCF LL-37 level than non-smoker CP group at baseline (p<0.05). GCF LL-37 levels significantly decreased in non-smoker CP group at first week, 1 and 3 months after completion of non-surgical periodontal treatment (p<0.05) although no significant decrease in GCF LL-37 levels was observed in smoker CP group (p>0.05). Periodontal parameters were correlated with GCF LL-37 levels in non-smoker CP group (p<0.05), but not in smoker CP group (p>0.05). GCF LL-37 levels do not seem to be affected from smoking in periodontal health. However, smoking might have a suppressive effect on GCF LL-37 levels in CP. Non-surgical treatment is effective in decreasing GCF LL-37 levels in non-smoker CP patients but not in smokers with CP.