2012 Fiscal Year Final Research Report

The Effect of Basic Mandibular Movement on the Head and Trunk

Research Project

Project/Area Number	22791877
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Single-year Grants
Research Field	Prosthetic dentistry
Research Institution	Niigata University
Principal Investigator	KINJOH Atsushi 新潟大学, 医歯学総合病院, 医員 (70464021)
Project Period (FY)	2010 – 2012
Keywords	顎関節症 / 下顎運動 / 頭部運動 / 疲労 / 全身と咬合 / 体幹動揺
Research Abstract	The purpose of this study was to investigate the effect of basic mandibular movement on the head and trunk and determine the relationship between the range of mouth opening and the range of head or trunk movement. The head moved backward during mouth-opening and moved forward during mouth-closing, when the subjects were standing. The body moved forward as mouth opened and backward while the mouth closed. The width of mouth opening was significantly correlated with the range of head and trunk movement. During open-close mandibular movements, associated head and trunk movements were observed. When the mouth opened, the head tilted backward, resulting in a shift of balance with the weight of the head over the cervical segments. To compensate for the backward head motion, the body tends to move forward, and vice versa. Also, a wider opening of the mouth was correlated to a larger range of head and trunk movements. These findings suggest that head and trunk movements facilitated smooth movement of the jaws.