The Study on the Influence of Nasal obstruction on Human masticatory behavior

Abstract

To study the influence of nasal obstruction on masticatory behavior, the water contents of the food bolus after chewing, the chewing time of foods, and the electromyographic activity (EMG) from the masseter muscle were measured in six adult subjects under both normal and abnormal conditions. The abnormal condition was simulated by pinching the nose. Peanuts, cookies, Japanese fried dough cakes “Karintou” and raw carrots were selected as the food items and the weights of normal bite-sized portions and chewing times to the point of normal swallowing were established for each subject. After the chewing period the food was not swallowed but spat into a weighed container for determination of the water contents of the food bolus.The cycle time and the duration of the masseter muscle activities until deglutition were also measured using surface electrodes.
The chewing times for each mouthful of food were statistically longer under the abnormal condition rather than in the normal condition. There were, however, no significant differences in the percent of the water content of the food bolus after chewing. When the condition was abnormal, the cycle time and interval time for each stroke were longer than under the normal condition. These findings suggest nasal obstruction leads to the disturbance of masticatory rhythms and to the extension of the chewing time.