The effects of cetylpyridinium chloride mouthwash combined with triamcinolone acetonide on oral microbiota and the Th17/Treg balance in patients with oral lichen planus

Background: Oral lichen planus (OLP) is a chronic inflammatory disease associated with oral microbiome imbalance and immune dysregulation. Objectives: To evaluate the effects of CPC mouthwash combined with triamcinolone acetonide on oral microbiota and Th17/Treg balance in erosive OLP patients. Methods: This study involved 80 patients with erosive OLP from January 2023 to January 2025. They were divided into: A control group treated with triamcinolone acetonide and a combination group treated with triamcinolone acetonide plus cetylpyridinium chloride mouthwash. After 4 weeks, primary outcomes included clinical efficacy, visual analog scale (VAS) pain scores, changes in signs and erosive area, oral salivary bacteria detection rate, Th17/Treg ratio, serum adipokine chemerin and cytokine levels (IL-17, TNF-?, IL-10) and OHIP-14 scores. Secondary outcomes were adverse reaction incidence and recurrence rates during follow-up. Results: The combination group showed better outcomes after 4 weeks of treatment. The total effective rate was 95%, higher than the control group's 80% (P=0.022). The combination group had superior pain relief (P=0.024), better mucosal repair (P=0.002) and a significant decrease in erosive area (P=0.021). It also had lower oral detection rates of Staphylococcus and Candida albicans (P<0.05). Immunologically, the combination therapy significantly reduced serum levels of chemerin, Th17 cells, Th17/Treg ratio, IL-17 and TNF-? (P<0.001), while increasing Treg cells and IL-10 levels (P=0.003), indicating stronger anti-inflammatory and immune-balancing effects. The combination group showed a greater reduction in the OHIP-14 score (P < 0.001), indicating improved oral health-related quality of life. No significant difference in adverse reactions was observed (P>0.05) and all were mild. The combination group had a lower recurrence rate within 3 months post-treatment, although the difference was not statistically significant (P=0.521). Conclusion: The combination of cetylpyridinium chloride mouthwash with triamcinolone acetonide effectively regulates the oral microbiota structure and restores the Th17/Treg immune balance in OLP patients.