Mouthwash has evolved from a cosmetic breath freshener to a functional adjunct in daily oral care. The effectiveness of mouthwash largely depends on its active ingredients, including chlorhexidine, fluoride, essential oils, cetylpyridinium chloride (CPC), povidone-iodine (PVP-I), and hydrogen peroxide. Each compound targets specific oral health concerns such as dental plaque, gingivitis, halitosis, and tooth decay. The renewed interest in antimicrobial rinses - especially during the COVID-19 pandemic - has also driven research into their antiviral roles and broader dental applications.

Chlorhexidine-based mouthwashes are among the most studied, demonstrating high-certainty evidence for significantly reducing dental plaque and gingivitis, particularly in short- and medium-term use (McGrath et al., 2023). Fluoride-containing rinses have moderate-quality evidence for reducing dental caries in children and adolescents. Essential oil formulations show notable reductions in plaque (32%) and gingival inflammation (24%) over placebo when used alongside mechanical oral hygiene. Meanwhile, CPC mouthwashes have shown modest but significant improvements in interproximal plaque and gingival health, although with high variability among studies.

PVP-I mouthwashes offer broad-spectrum antimicrobial action and have shown promise in reducing gingival pocket depth and aiding post-surgical healing. Hydrogen peroxide, though commonly used for its whitening effects, has weak clinical evidence for long-term improvements in plaque or gum health. Alcohol-free formulations are recommended for individuals with xerostomia or oral sensitivity, providing the same benefits without discomfort. While concerns exist about mouthwash altering the oral microbiome, short-term use appears to present minimal risk (Chan, 2024).

Despite these benefits, mouthwash should not replace brushing and flossing. It functions best as a supplementary measure, especially in cases of orthodontic care, post-surgery recovery, or high caries risk. Long-term use, particularly of chlorhexidine, may cause tooth staining or taste alteration, reinforcing the need for dental supervision.