In 9 healthy dentate, the hardness of 31 foods before and after chewing until swallowing threshold was measured by the creepmeter, and the number of chewing stroke until swallowing threshold was counted in order to investigate the change in rheological properties by mastication. Masticatory performance in each subject was measured by the sieving method suggested by Kapur et al.
The results obtained are as follows.
1. The hardness of each food before chewing corresponded with the grades of masticatory difficulty of the food intake questionnaire.
2. The number of chewing strokes until swallowing threshold varied depending on the hardness of each food before chewing.
3. The hardness of 31 food bolus in swallowing threshold after chewing was less than 30kPa, independently of the degree of food intake difficulties of the questionnaire on masticatory function.
4. In peanut mastication, there was statistically significant correlation between the number of chewing strokes until swallowing threshold and masticatory performance (r=-0.87, p<0.01).
In the study, the result showed that the decision indicator in swallowing threshold was the hardness of bolus. Moreover, it was suggested that the hardness of bolus in swallowing threshold and the number of chewing strokes until swallowing threshold are useful for evaluation of the function.