Objectives: The aim of this study was to examine the relation between the degree of tongue-coating and oral function.
Background: Tongue-coating is a moss-like deposit which forms over the tongue surface, and includes micro-organisms, food residues, and abrasive epithelia. It is considered that motor function of the tongue and lips and saliva secretion decrease in the aged and have some effect on the accumulation of tongue-coating. Although saliva secretion has been reported as a factor amongst these oral functions in contributing to tongue-coating, the correlation with the motor function of oral structures is unknown.
Subjects and methods: The factors that contribute to the accumulation of tongue-coating were examined in 48 subjects of advanced age (mean age 80.8 +/- 7.8 years) with no severe levels of periodontal disease. Changes in the degree of tongue-coating were also examined after oral functional training in these subjects. The frequency of oral cleaning, status of oral hygiene, motor function of the tongue, and masticatory performance were examined as potential factors associated with the degree of coating.
Results: The results showed that tongue pressure and the frequency of oral diadochokinesis measured by pronouncing the single syllable 'ka' as an indicator were statistically significantly correlated with the degree of tongue-coating. Several factors in oral function improved with training, and also the degree of tongue-coating decreased in 27 subjects.
Conclusion: These results suggest a correlation between the degree of tongue-coating and a reduction in lingual motor function and, in addition, possible improvement in level of coating by functional training of the tongue.