Efficacy of chitosan hydrogel as an Adjunct to Scaling and Root Planning for reducing microbial count and inflammatory levels in gingival crevicular fluid of patients with chronic periodontitis: Randomized Clinical Trial

Abstract

Nonsurgical periodontal therapy presented in scaling and root planning (SRP) represents the gold standard management of chronic periodontal disease. On the other hand, inaccessible remaining subgingival biofilm and unmodulated host inflammatory response hinder the effectiveness of SRP. Thus, appropriate adjunct therapy should be considered. The natural polysaccharide chitosan has antimicrobial, anti-inflammatory, and biodegradable characteristics that nominated it as adjunct therapy to be chosen for potential efficacy. This randomized clinical trial aimed to evaluate the adjunctive chitosan hydrogel combined with SRP on subgingival microbial load and gingival crevicular fluid (GCF) inflammatory cytokine level over six weeks. A sample of 126 patients diagnosed with chronic periodontitis were equally randomly allocated to two groups; test group (SRP+ adjunct chitosan hydrogel alone, n = 63), and control group (SRP alone, n = 63). Outcomes were evaluated by collecting GCF samples from all participants at baseline and six weeks post-treatment. Colony-forming units per milliliter were used to quantify bacterial load, and ELISA assay was used to measure concentrations of interleukins 17 (IL-17) and 18 (IL-18) concentrations. At six weeks, the test group exhibited significantly greater reductions in microbial count (1.45 ± 0.4 × 10³ vs. 3.12 ± 0.6 × 10⁵ CFU/mL, p < 0.001) and in GCF concentrations of IL-17 (6.1 ± 1.2 vs. 14.2 ± 2.1 pg/µL, p < 0.001) and IL-18 (74.5 ± 12.4 vs. 105.8 ± 18.2 pg/µL, p < 0.001) when compared to SRP alone. Intra-pocket chitosan hydrogel application makedly reduced subgingival bacterial load and pro-inflammatory cytokines, indicating its potential as an effective local adjunctive therapy. The experiment was retrospectively registered with the Thai Clinical Trials Registry under the registration number TCTR20260829007 on August 29, 2026.