Non-surgical periodontal treatment effects on IL-17 and IL-35 levels in smokers and non-smokers with periodontitis.

Periodontitis, a chronic inflammatory disease influenced by host-microbiota interactions, poses a significant global health burden. Smoking exacerbates periodontitis progression and impacts treatment outcomes. Interleukin (IL)-17 and IL-35 are key mediators of inflammation, yet their roles in smoking-related periodontitis and responses to non-surgical periodontal treatment (NSPT) remain underexplored. This clinical trial aimed to evaluate the effects of NSPT on salivary and gingival crevicular fluid (GCF) levels of IL-17 and IL-35 in smokers and non-smokers with periodontitis. A total of 55 subjects were divided into three groups: smokers with periodontitis (SP), non-smokers with periodontitis (NSP), and healthy controls (C). All subjects underwent comprehensive periodontal assessments and cytokine level analyses at baseline and four weeks post-NSPT. Saliva and GCF samples were analysed for IL-17 and IL-35 using enzyme-linked immunosorbent assay (ELISA). Statistical analyses evaluated group differences and correlations. After NSPT, both SP and NSP groups exhibited significant improvements in clinical parameters (p < 0.05). Salivary IL-17 and IL-35 levels did not show significant differences between the SP, NSP, and C groups after NSPT (p > 0.05). However, in GCF, IL-17 and IL-35 concentrations significantly increased in both SP and NSP groups following NSPT (p < 0.05). The total amount of GCF IL-17 decreased significantly only in the NSP group after NSPT (p < 0.05), while the total amount of GCF IL-35 increased significantly in both SP and NSP groups (p < 0.05). Strong correlations between IL-17 and IL-35 levels in both saliva and GCF were observed. NSPT modulates inflammatory and anti-inflammatory cytokine profiles, promoting improved clinical outcomes. The impact of smoking on cytokine responses highlights the need for further research to elucidate the mechanisms underlying these cytokine modulations and their role in periodontal therapy. Trial registration ClinicalTrials.gov ( https://clinicaltrials.gov -01.01.2018-NCT05281848).