Evaluation of bolus formation in masticatory function by using videoendoscopy

Abstract

In the field of prosthodontics, many methods for evaluating the masticatory function were carried out by ejection of the food bolus from the mouth. Yet, these methods could not evaluate mastication and swallowing function comprehensively. The purpose of present study is to evaluate masticatory functions during a series of masticatory and swallowing movements by using videoendoscopy (VE). Subjects are ten healthy dentulous adults without dysphagia. The test foods used were two-colored (green and white) molded rice and uirou. The test foods were consumed under the restriction on the number of mastication (10, 15, 20, and 30). The food bolus in the oropharynx was evaluated qualitatively by using VE in terms of the degree of grindability, cohesiveness, and mixing. In addition, the degree of easiness of swallowing was measured with visual analogue scale (VAS). In both rice and uirou, degree of cohesiveness showed a constant high value under all conditions. The significant correlation coefficients were observed between the number of mastication, the degree of grindability, and mixing. In addition, the significant correlation coefficients were observed between the value of VAS, degree of grindability, mixing, and the number of mastication. The present study demonstrates that VE can be applicable for evaluating the masticatory function, although the aim of VE has so far been limited to the evaluation of swallowing in the pharyngeal stage. And also, although these results suggest that adequate mastication induces smooth swallowing, it could be adjusted to the degree of grindability and mixing of food bolus by mastication.