Effect of masticatory movements on head and trunk sways, and sitting and foot pressure distributions during sitting...

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, 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.

The 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.

A 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.

Total 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).

Masticatory movements affect sitting pressure distribution and head movements during sitting position.