Comparison of the Efficacy of Three Types of Disinfectants Approved for Oral Use in Japan in Reducing the Bacterial Count of Tongue Coating: A Randomised-Controlled Study.

Purpose Tongue coating is one of the primary causes of halitosis and some diseases such as aspiration pneumonia. However, to date, an effective method for reducing the bacterial count of tongue coating has not been established. We conducted a randomised-controlled study to compare the efficacy of three types of disinfectants approved for oral use in Japan in reducing the bacterial count of tongue coating. Materials and methods Thirty-two participants were randomly assigned to the following four groups according to the solution used: 1. benzethonium chloride; 2. povidone iodine; 3. hydrogen peroxide; 4. tap water (control group). Tongue cleaning with the three test disinfectants and water was performed using a toothbrush, and the bacterial count on the tongue dorsum before and after tongue cleaning was measured using the Rapid Oral Bacteria Quantification System. Results The bacterial count decreased statistically significantly after tongue brushing using povidone iodine and hydrogen peroxide solutions (both p = 0.012), but not after brushing using 0.2% benzethonium chloride and tap water. Conclusion Tongue brushing with povidone iodine or hydrogen peroxide was the most effective method for reducing the bacterial count of tongue coating.