Efficacy of Cetylpyridinium Chloride Mouthwash on Denture Plaque Reduction and Microbiome Alteration in a Randomized Crossover Trial

Purpose This study aimed to evaluate the effectiveness of cetylpyridinium chloride (CPC) mouthwash in reducing denture plaque and its impact on the microbial composition of denture plaque. Materials and methods A randomized, placebo-controlled crossover trial included 29 participants with maxillary complete dentures. Participants used either CPC or a placebo mouthwash for one week each in a crossover design. The denture plaque area was quantified using image analysis, and microbiome composition was analyzed via 16S rRNA gene sequencing. Results The use of CPC mouthwash significantly reduced the denture plaque area compared to placebo (p<0.025). Microbiome analysis revealed a significant decrease in the relative abundance of the genus Actinomyces (p=0.025) and a significant increase in the genus Haemophilus (p<0.001) after CPC use. While alpha diversity showed no significant changes, beta diversity analysis indicated a significant shift in microbial composition (p=0.002). Conclusion CPC mouthwash effectively reduces denture plaque accumulation and modifies its microbial composition. These findings highlight the potential of CPC mouthwash as an effective tool in denture hygiene management, which may help lower the risk of denture-related oral and systemic infections.