Evaluation of Potential Effect of Menthol Solution on Oral Hygiene Status of Dental Students in a University in Iraq

Purpose: To test the effect of menthol extract on the oral hygiene status of dental students of Faculty of Dentistry, Al-Mustansiriya University, Baghdad, Iraq. Methods: A solution (18 mg %) of menthol was prepared by dissolving menthol crystals in absolute ethanol. Chlorhexidine (CHX, 0.2 %) and deionized water were used as positive and negative controls, respectively. Menthol was examined for its toxic effect. Twenty male albino mice were injected intraperitoneally with a low (10 mg/ml) and high dose (50 mg/ml) of the menthol solution, and acute toxicity (LD50) calculated. A double-blind crossover was designed to test plaque re-growth over 5 days. Thirty male dental student volunteers were asked to cease tooth cleaning and then rinse with 10 ml of menthol solution three times daily for 1.5 min, twice daily with CHX and deionized water. Plaque, gingival and bleeding scores were recorded on days 0 and 5. A washout period of 2 weeks was allowed, and then a new test was initiated. The data obtained were analysed statistically. Results: Menthol mouthwash demonstrates a significant reduction in plaque, gingival and bleeding indices of 0.56, 0.45 and 0.03, respectively. CHX induced a greater reduction in these parameters than menthol with indices of 0.14, 0.26, and 0.04, respectively. Conclusion: Menthol mouth rinse (0.018 %) is an antiplaque and anti-gingivitis agent, though less effective than CHX.