Effects of masticatory movements on the head, trunk and body sway during the standing position

Abstract

Introduction Mastication involves complex tongue movements, coordination of lip, and cheek movements and is associated with head movement to facilitate the intraoral transport of food from ingesting to swallowing; it affects many functions of the whole body. However, studies to evaluate the relationship between masticatory movements and the body posture are still lacking to our knowledge. The purpose of this study was to characterize the effects of masticatory movements on the head, trunk, and body sway during the standing position. Methodology A total of 30 healthy subjects were evaluated. The MatScanTM system was used to analyze changes in body posture (center of foot pressure: COP) and the 3-dimensional motion analysis system was used to analyze changes in the head and trunk postures while subjects remained in the standing position with the rest position, centric occlusion, and masticating chewing gum. Results The total trajectory length of COP and head and trunk sways during masticating chewing gum were significantly shorter and smaller respectively than it was in the rest position and centric occlusion (p<0.016). COP area during masticating chewing gum was significantly smaller than it was in the 2 mandibular positions (p<0.016). Conclusion Masticatory movements positively affect the stability of the head, trunk, and body sways and enhance the postural stability during the standing position.

Correlations of head and trunk sways, and sitting and foot pressure distributions during chewing in the sitting position

“…The MatScan TM system (Tekscan Inc., South Boston, MA, USA, Nitta Corp., Osaka, Japan) [13,14,[20][21][22] was used to analyze foot pressure distribution. This instrument provided a dynamic evaluation of foot pressure distribution.…”

“…The three-dimensional motion analysis system (Library Co., Ltd., Tokyo, Japan) was used to analyze head and trunk sways [13,14]. This instrument enabled measurement of three-dimensional movements of target points on the surface of the facial skin and body surface simultaneously.…”

“…The movements of target points were recorded by three charge coupled device (CCD) cameras, and the three-dimensional coordinates were calculated by using analyzing software (Library Co., Ltd, Tokyo, Japan). Target points on the skin of the face and the trunk were marked by attaching 4 points respectively [13,14] (Figure 2). The center of 4 target points was calculated in each sampling frame.…”

“…The trunk sway was analyzed based on the coordinate system on the ground [13,14]. For all tests, subjects were asked to remove their shoes and socks, to seat with hip and knee joints at 90°flexion position on the height adjustable chair, and to cross their arms at the anterior chest to minimize the effect of their arms on the posture [14] (Figure 2).…”

“…Researchers have also investigated the relationship between mastication and body posture [11][12][13], and suggest the possibility that mastication affects the postural control by enhancing the postural stability. All these reports examined the relationship between mastication and standing posture.…”