Halitosis Relief Effect of Mouthwash Containing Lespedeza cuneata Extract: A Randomised, Double-Blind, Placebo-Controlled Study

Purpose: To evaluate the effect of a mouthwash containing Lespedeza cuneata extract (LCE) on halitosis as an alternative to chemical mouthwashes. The effect of this natural mouthwash on halitosis-causing bacteria (HCB) was clinically evaluated.
Materials and Methods: A total of 84 subjects among 103 participants were recruited from the M Dental Clinic (Busan, South Korea) in this randomised, double-blind, placebo-controlled study. The participants were divided into two groups: 41 in the saline-gargle group (saline group) and 43 in the LCE-gargle group (LCE group). A week before the experiment, scaling and oral health education were conducted to standardise the subjects’ oral condition. For clinical evaluation, halitosis and HCB were evaluated pre-gargle (baseline), immediately after gargling (treatment), and 5 days after gargling (5 days post-treatment). Statistical analysis was performed using SPSS for Windows.
Results: The level of subjective improvement was statistically significantly greater in the LCE group than the saline group (p < 0.05). Compared with the saline group, the LCE group showed reduced halitosis after 5 days of application. Furthermore, halitosis statistically significantly decreased over time (p < 0.05). Moreover, the LCE group showed a statistically significant decrease in the number of all six HCBs (p < 0.05).
Conclusion: LCE gargle was effective in reducing halitosis both subjectively and objectively, suggesting an antibacterial effect on HCBs in the oral cavity. Thus, LCE, which can be used as a safe mouthwash ingredient, can promote oral health and will be valuable for the oral healthcare product industry. It might also be helpful for people suffering from halitosis.