Effects of Tongue Cleaning on Tongue Coating and Dental Plaque

Objectives: Previous investigations on the effect of tongue cleaning on tongue coating and plaque accumulation have reported contradicting results. This study aimed to correlate tongue coating with dental plaque accumulation in individuals who perform tongue cleaning.
Methods: The study was approved by the Research Committee of the College and informed consent was obtained from the subjects. An examiner-blind, randomized clinical trial with crossover design was employed. Ten dentistry students participated in the study. At baseline, a single calibrated examiner assessed plaque index (PI) using the Turesky modification of Quigley and Hein, while a different calibrated examiner assessed tongue coating color and thickness, based on the method of Gómez et al. (2001). The subjects were randomly allocated to either a group that performed twice daily tooth brushing, or those who did twice daily tooth brushing with tongue cleaning. The subjects were dismissed and after 2 weeks, plaque indices and tongue coating scores were again recorded. A two-week washout period was implemented before crossover to the second round.
Results: Baseline plaque indices and tongue coating scores of the two groups were comparable. After 2 weeks, a decrease in mean PI, while an increase in tongue coating color and thickness were observed in both groups. These changes however, were not statistically significant. Likewise, a comparison between groups yielded no significant difference (p>0.05 using T-test). Correlation between PI and tongue coating revealed inverse relationship. However, using Pearson’s correlation coefficient, the correlation was statistically insignificant for both groups (p>0.05).
Conclusions: Based on the results, tongue cleaning appears to be ineffective in reducing plaque accumulation. Moreover, no correlation was observed between tongue coating and plaque scores. However, based on previous investigations, the authors do not advise abandonment of tongue cleaning as part of oral hygiene, because of other reported benefits such as control of halitosis.