Influence of voluntary teeth clenching on the stabilization of postural stance disturbed by electrical stimulation of unilateral lower limb
Introduction
In recent years, an increasing number of analyses have been made of the possible correlation of teeth clenching with the efficiency of motor performance as well as muscle strength of the extremities [1], [2], [3], [4]. Previous studies in our laboratory investigated the relationship between teeth clenching and isometric muscle strength of the upper and lower extremities in healthy volunteer subjects, and revealed a possible correlation between the magnitude of muscle strength required and the force of teeth clenching [1], [3]. Moreover, Sumita et al. studied the relationship between voluntary teeth clenching and the isokinetic strength of lower extremities in healthy volunteer subjects, and demonstrated that teeth clenching had the effect of increasing isokinetic muscle strength at lower angular velocities [2].
On the other hand, studies on the relationship between dental occlusion and body balance have suggested that occlusion status contributes to the maintenance of postural balance. As an example, it has been reported that altering dental occlusion by wearing an occlusal splint could make certain subjects modify their postural attitude through the use of Fukuda-Unterberger experimental stepping test to check the postural attitude [5]. Additionally, Hosoda et al. demonstrated that occlusion could bring about the maintenance of postural balance when unexpected swaying occurred in the standing position by use of EquiTest (MPS-3100, NeroCom, OR, USA) dynamic posturographic model [6]. To date, however, little has been reported about the effects of voluntary teeth clenching on the stabilization of postural stance in perturbation, which was introduced by electrical stimulation of a unilateral lower limb. In the present study, we elucidated whether teeth clenching influenced adaptation to the novel environment.
Section snippets
Subjects
Experiments were performed on 12 young adults (10 males and two females: aged 28.50 ± 4.64 years; height 170.88 ± 8.39 cm; body mass 64.16 ± 12.92 kg mean ± SD). All subjects had stable intercuspal position without malocclusion, toothache, pain of orofacial muscles, temporomandibular joint problems or a previous history of injury in the lower extremities. The study was approved by the Ethical Committee for Human Research, Faculty of Dentistry, Tokyo Medical and Dental University and the subjects gave
Results
Fig. 3 illustrates an example of the time course of GRF/BM after electrical stimulation of the right lower limb obtained from a subject. Every component wave comprising the GRF/BM in the A/P direction decreased in amplitude during CL compared to CO.
Table 1 shows the values of the peak-to-peak amplitude and the peak time of GRF/BM, in the A/P and M/L directions, respectively. The peak-to-peak amplitude of GRF/BM in the A/P direction under conditions of CL was significantly smaller than that of
Discussion
The present study demonstrated that when a disturbed postural stance was generated by electrical stimulation of a unilateral lower limb: (1) the peak-to-peak amplitude of GRF/BM in the A/P direction with CL was significantly smaller than that with CO, (2) the peak time of GRF/BM in the A/P direction occurred earlier in CL than in CO, and (3) the integrals of the GRF/BM under conditions of CL tended to be smaller than those of CO in the A/P direction.
Numerous analyses of the possible correlation
Conflict of interest
No authors have any conflict of interest that may have biased this work.
References (14)
- et al.
Effect of occlusion status on the time required for initiation of recovery in response to external disturbances in the standing position
Clin Biomech
(2007) - et al.
Occlusion and center of foot pressure variation: is there a relationship?
J Prosthet Dent
(1996) Dental occlusion and body posture: no detectable correlation
Gait Posture
(2006)- et al.
Posture stability and unilateral posterior crossbite: is there a relationship ?
Neurosci Lett
(2006) - et al.
Unilateral trigeminal anesthesia modifies postural control in human subjects
Neurosci Lett
(2002) - et al.
Effect of teeth clenching on isometric and isokinetic strength plantar flexion
J Med Dent Sci
(1998) - et al.
Effect of teeth clenching on force–velocity relationships in isokinetic knee extension
Jpn J Phys Fitness Sports Med
(1999)
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