The tongue surface in older people requiring nursing care is often coated with a layer believed to comprise, keratinized products of degeneration, food residue, bacteria, and leukocytes attached to the tongue papillae. Which factors affect the status of this tongue coating remain to be elucidated, however. The purpose of this study was to evaluate factors related to tongue coating status in older people requiring nursing care. The study participants comprised 41 individuals admitted to special nursing homes for the elderly. After undergoing tooth brushing and tongue cleaning by the facility staff, the participants were required to refrain from oral cleaning until evaluation of tongue coating status, which was performed just after lunch. The moisture level of the tongue surface was measured and total number of oral microbes determined. Food type, care level, and sex were determined by a questionnaire given by the attending nurses. Correlations between the tongue coating status and various factors were analyzed using Spearman's rank correlation coefficient. The participants were divided into 2 groups according to the median value of the tongue coating status. Factors related to tongue coating were analyzed using binomial logistic regression analysis (α=0.05). Tongue coating status showed a significant correlation with the total number of oral microbes on the tongue surface (r=0.449, p=0.003), type of food (r=0.388, p=0.012), and care level (r=-0.308, p=0.050). Logistic regression analysis revealed that the food type of the side dish significantly affected tongue coating status. These results showed a correlation between tongue coating status and type of food of the side dish in older people requiring nursing care.

Tongue cleaning with mouth moisturising gel decreased the number of microbes on the tongue surface immediately after cleaning, and tongue cleaning with mouthwash decreased it for 5 hours.