A study of the relationship between posterior unilateral biting tasks and body sway

The influences of head and body posture on physiologic rest position, range of functional movements and initial tooth contact have previously been reported. The purpose of this study was to investigate whether the posture of the body can be modified by alterations in the stomatognathic system. Postural sway was assessed in 8 healthy subjects. We recorded the subjects' center of gravity (CG) during natural standing in physiologic rest position (with eyes open or closed), while biting on one sheet of occlusal registration paper without clenching on the left and the right sides (with eyes closed) . The dominant side of the velocity vector of CG (DSVV) was determined by comparing the total value of magnitudes in right and left ingredients of the velocity vector. In each subject, the DSVV coincided with the side for which the subject presented a smaller value of total sway length of center of gravity (LNG) . The LNG values with eyes open were significantly smaller than those with eyes closed. The LNG values obtained when subjects were biting on the occlusal registration paper placed on the ipsilateral side to the DSVV were significantly smaller than those obtained when they were biting on the contralateral side to the DSVV. The results suggest that there could be a dominant side for the CG in normal subjects and this condition might be more stabilized with biting on the ipsilateral side of DSVV.