TITLE:
In Vitro Comparison of Four Listerine Mouthwash Formulations on the Inhibition of Lactobacillus reuteri DSM 17938 and Human Oral Microbiota
AUTHORS:
Jinxi Mo
KEYWORDS:
Oral Bacteria, Probiotic, Listerine Mouthwashes, Antibacterial Effects
JOURNAL NAME:
Open Journal of Stomatology,
Vol.16 No.4,
April
21,
2026
ABSTRACT: Listerine mouthwashes are the most widely used over-the-counter and common daily supplies for people to maintain oral health and hygiene. However, few study reveals the differences between types of mouthwash and compares the influence they each might bring to oral probiotics and general oral bacteria. In this experiment, Lactobacillus reuteri DSM17938 and human saliva samples of different concentrations are set and each cultivated to represent significant oral probiotics and potential bacteria in human saliva, including pathogens, for further comparison. Mouthwashes are added onto agar plates and into liquid saliva samples to reflect differential inhibitory effects possibly due to variations in compositions. Results from gar plate diffusion assay have shown that cosmetic mouthwash is the most effective in inhibiting both Lactobacillus reuteri DSM17938 and oral bacteria’s growth, indicating both an advantages and risk of the application of cosmetic mouthwash. While liquid culture analysis suggest that alcohol mouthwashes have the most immediate antibacterial effects but tend to be a short-term treatment for inhibition and alleviation, lacking the ability for complete, long-term solution.