In Japan, a country with an aging population, hyposalivation is becoming a serious problem among the elderly. The purpose of this study was to develop a new method for promoting salivary secretion using the olfactory stimulus of Citrus sudachi, artificial sudachi fragrance, and the combined use of artificial sudachi fragrance with thermo stimulus. Olfactory stimulus of Citrus sudachi is known as a safe stimulus that can stimulate salivary secretion of patients before food intake. However, Citrus sudachi is a seasonal fruit, so its effect was compared to that of artificial sudachi fragrance. The amount of saliva was recorded to evaluate the effect among 94 healthy adult participants who signed an informed consent form approved by the Research Ethics Committee of Tokushima University Hospital (#1283). Since olfactory stimulus easily fades, thermo stimulus was used because it is known to increase salivary secretion continuously. Thus,the effect of artificial sudachi fragrance combined with thermo stimulus using a hot pack on three different parts of the body (eyes, submandibular, chest) was also examined. Changes in salivary secretion was recorded for 1 hour after the stimulation. Results showed that artificial sudachi fragrance increased salivary secretion as much as Citrus sudachi. There was no significant difference between the olfactory stimuli of artificial sudachi fragrance when used alone, and when used in combination with thermo stimulus. However, it was observed that the stimulus which increased salivary secretion the most in 50 minutes was the olfactory stimulus with thermo stimulus on the submandibular. It can therefore be said that the combined use of olfactory stimulus with thermo stimulus is useful when saliva secretion becomes a concern among the elderly, especially at the start of food intake.

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Membranous substances are sometimes observed on the dorsum of the tongue, teeth and buccal mucosa in elderly persons requiring nursing care, but the cause of such formation has not yet been elucidated. In this study, the membranous substances sampled from elderly persons requiring nursing care were microscopically observed, the presence of epithelial components was confirmed, and an investigation was conducted regarding the formative cause of membranous substances with epithelial components. The subjects were 70 elderly persons requiring nursing care in C hospital who were 65-years or older (81.1±7.7 years old). In addition to investigating age, disorders, commonly used agents, the degree of mobility (severity of bedridden state), the level of consciousness, the presence of communication, the ability of speech, and the frequency of assisted tooth-brushing from hospital records, an evaluation was carried out on the gingival index. The presence of an open-mouth state, as well as the degree of moisture retention of the mucous membrane of the tongue was also observed. Decision tree analysis was carried out with the presence of each membranous substance formation as the dependent variable. The condition of food ingestion was closely involved in the formation of membranous substances inside the oral cavity of elderly persons requiring nursing care, suggesting that non-oral ingestion was the cause for such formation. The major cause of membranous substance formation was the dryness of the oral membrane. It was suggested that the prevention of oral dryness may prevent membranous substance formation in the oral cavity.

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Retention and stability are essential for the success of complete denture treatment. Previously, evaluation of complete denture retention forces required large equipment, and it was difficult to perform chair-side evaluation. Therefore, we developed a compact device that can measure the retention forces. The purpose of this paper was to determine the reproducibility of this newly-developed retention measuring system using various oral moisturizers. The newly-developed retention measuring system consisted of a metal spatula and a strain gauge. Palatal plates were made for 14 healthy dentate individuals. Three oral moisturizers, namely artificial saliva, and liquid-type and gel-type moisturizers, were used between the palate and palatal plates. The palatal plate was pressed on the palate for 10 seconds and then pulled at a certain speed. Retention forces were recorded when the palatal plate detached. The retention force of the palatal plate increased in the following order： artificial saliva, liquid moisturizer and gel moisturizer. Retention force varied from 0.9 to 17.7 N. The standard deviation of measured values with different mediating fluids for individual subjects was relatively small, indicating little variation. In addition, three-way ANOVA showed significant differences when comparing between subjects and when comparing subjects and mediating fluid type (p＜0.05), however repetition was not significant (p＝0.346). These findings demonstrate that the newly-developed retention force measuring device can measure various retention forces, and the device has good reproducibility when used intraorally. This suggests that the device could be used for chair-side measurement.

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[in Japanese]

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We examined the relationship between oral function and the ability to touch the tip of the tongue to the corners of the mouth among community-dwelling dependent elderly individuals. The subjects were 183 community-dwelling dependent elderly individuals residing in Hyogo Prefecture, Japan. Data were collected through a questionnaire and a field survey. We obtained data on age, gender, level of independence, swallowing function, tongue pressure, labial closure force, and the ability to touch the tip of the tongue to the corners of the mouth. The RSST (Repetitive Saliva Swallowing Test) was performed to evaluate the swallowing function. In order to evaluate their lateral tongue movement, the subjects were asked to touch the left and right corners of their mouths with the tips of their tongues in turn for five seconds. The average score on the RSST was 2.63±1.31, and the mean tongue pressure was 23.11±10.89 kPa. The subjectsʼaverage lip power was 10.64±6.28 N, and the average tongue movement score was 6.13±2.78. Their ability to touch the tip of the tongue to the corners of the mouth was significantly related to their RSST, tongue pressure and lip power scores respectively. Our results suggest that the tongue movement is significantly related to subjective assessment of oral function among community-dwelling dependent elderly individuals.

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[in Japanese]

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