BackgroundThe head plays an important role in the postural control. Chewing co‐activates jaw and neck muscles leading to coordinated jaw and head‐neck movements. Therefore, to examine effect of masticatory movements on head and trunk sways, and sitting and foot pressure distributions during mastication is helpful in the attempt to understand the interrelationship between stomatognathic function and posture control system in the sitting position.ObjectivesThe purpose of this study was to test the hypothesis in healthy subjects that masticatory movements affect head and trunk sways and sitting and foot pressure distributions during sitting position.MethodsA total of 30 healthy male subjects with an average age of 25.3  years (range, 22–32  years) were evaluated. The CONFORMat™ and MatScan™ system were used to analyse changes in sitting pressure distribution center of sitting pressure (COSP) and changes in foot pressure distribution center of foot pressure (COFP), respectively, and the three‐dimensional motion analysis system was used to analyse changes in head and trunk postures while subjects remained sitting position with rest position, centric occlusion and chewing. The total trajectory length of COSP/COFP, COSP/COFP area, and head and trunk sway values were compared between the three conditions to evaluate whether masticatory movement affected the stability of head and trunk sways and sitting and foot pressure distributions.ResultsTotal trajectory length of COSP and COSP area during chewing were significantly shorter and smaller respectively than it was in rest position and centric occlusion (p  ⟨  .016). Head sway value during chewing was significantly larger than it was in rest position and centric occlusion (p  ⟨  .016).ConclusionMasticatory movements affect sitting pressure distribution and head movements during sitting position.

Purpose:The head plays an important role in the postural control. Chewing co-activates jaw and neck muscles leading to coordinated jaw and head-neck movements. Therefore, examination of the relationships among head and trunk sways, and sitting and foot pressure distributions during chewing is helpful in the attempt to understand an interrelationship between chewing and posture control system in the sitting position. This purpose of this study was to examine what kind of correlation exists among head and trunk sways, and sitting and foot pressure distributions during chewing in the sitting position. Methods: A total of 32 healthy young male subjects were evaluated. The CONFORMat TM and MatScan TM system were used to analyze changes in sitting pressure distribution (center of sitting pressure: COSP) and changes in foot pressure distribution (center of foot pressure: COFP) respectively, and the three-dimensional motion analysis system was used to analyze changes in head and trunk positions while subjects remained sitting position with rest position, centric occlusion, and chewing. Data were analyzed using Spearman's rank correlation coefficients. Results: There was a significant positive correlation between head and trunk sways in all three studied test conditions (correlation 0.76 to 0.92, P < 0.01). During chewing, significant positive correlations were also found between head sway and the displacement of COFP (correlations 0.64 and 0.65, P < 0.05) and between trunk sway and the displacement of COSP (correlations 0.66 and 0.75, P < 0.05). Conclusions: This study confirmed that there were significant positive correlations between head and trunk sways, between head sway and foot pressure distribution, and between trunk sway and siting pressure distribution during chewing in the sitting position.

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.