Oral physiological analysis of dysphagia-relation of feeding posture and the masticatory movement-

2004 Fiscal Year Final Research Report Summary

• Project/Area Number: 15390613
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Surgical dentistry
• Research Institution: Osaka University
• Principal Investigator: IIDA Seiji Osaka University, Dental Hospital, Associate Professor, 歯学部附属病院, 講師 (40283791)
• Co-Investigator(Kenkyū-buntansha): MASUDA Yuji Matsumoto Dental University, Institute for Oral Science, Professor, 総合歯科医学研究所, 教授 (20190366) ; KOGO Mikihiko Osaka University, Graduate School of Dentistry, Professor, 大学院・歯学研究科, 教授 (20205371)
• Project Period (FY): 2003 – 2004
• Keywords: dysphagia / mastication / jaw movement / masticatory performance / posture

Research Abstract

This research was performed to clarify the influence of the masticatory head posture on the performance of mastication and to show the influence of the difficulty of mastication on occurrence of dysphagia.
10 healthy young adult was recruited as the subjects and the masticatory movement was assessed by the muscle activity of both digastric and masseter muscles and the number of jaw movement, masticatory performance analyzed by gummy jelly procedure, and jaw movement analysis by mandibular kinesiograph(gnathohexagraph).
The results were summarized as follow.
The analysis of the number of jaw movements during freely mastication revealed the decreases of this movements according to the change of body posture toward supine position and the duration of mastication also decreased. This trend is more significantly observed in the condition of the feeding the foods with water. The performances of mastication using gummy jelly were decreased according to the changes of body posture toward the supine position. Analysis of jaw movements revealed the shortened time of each masticatory cycles in the supine position and the speed of crashing the foods also delayed in the supine position.
Another analysis of the masticatory movement using systemic administration of Dopamine agonists in freely moving rats well showed the importance of palatal sensation for tongue movements.
In conclusion, the changes of body during mastication causes the difficulty of jaw and tongue movements and the changes of them also produced by the location of the foods in oral cavity. These difficulty of mastication may be one of most considerable causes of dysphagia in elderly.