Effects of Changes of Mandibular position and Mandibular movement on Distribution of Foot Bottom Pressure

采用足底压力测量仪，对下颌运动过程中的足底压力分布进行了研究。6例口腔颌面系统无主客观异常、平衡功能正常的健康人作为研究对象。受试者被认为是主观上意识到主要习惯咀嚼的一面。选择下颌骨静止位置和左右咀嚼口香糖作为下颌运动的测试条件。此外，还进行了习惯咀嚼侧和另一侧的口香糖咀嚼试验，发现左右咀嚼口香糖时的身体摆动小于下颌骨的静止位置。这与以前报告的结果是一致的。当身体摆动被分析为X、Y分量的泛函时，下颌静止位置和左右咀嚼…之间的身体摆动的X分量(左-右)没有显著差异再来一次。前后Y分量差异显著，即咀嚼口香糖时的身体摆动小于下颌骨静止时的摆动。由于在习惯的咀嚼侧测试中对身体摆动的分析也发现了类似的趋势，因此很可能每个受试者的咀嚼侧都没有影响。根据这些结果估计足底压力分布时，左右咀嚼口香糖试验中检测到足底压力的点数多于下颌骨试验的静止位置。而前者的压力也较大。由此可见，嚼口香糖对足底压力的分布有很大的影响。目前的结果表明，受试者在脚底保持平衡，适应咀嚼口香糖的下颌运动，以及与运动相关的头部位置变化。此外，还测量了护口器加载过程中的足底压力。对受试者应用ADA规定的定制的4型护口器。结果表明，下颌骨静止位置和护口器负重时间对身体摆动无显著影响。因此，护口器的负荷对身体摇摆的影响很小。

An investigation was made on the distribution of foot bottom pressure during the mandibular movements using a measuring apparatus for foot bottom pressure. Six healthy persons who had no subjective and objective abnormalities in the stomatognathic system and the equilibrium functions were used as the subjects. The subjects were regarded to be subjectively aware of the major habitual chewing side. The rest position of mandibule and the left-right gum chewing were chosen as the test conditions of mandibular movement. Furthermore, gum chewing test in both the habitual chewing side and the other side was performed and the body sway was found smaller during left-right gum chewing than in the rest position of mandibule. This was consistent with the results of previous reports. When body sway was analyzed as the fundions of X,Y-components, significant differences in the X-component (left-right) of the body sway were not found between the rest position of mandibule and the left-right gum chewi … More ng. The differences in Y-component (antero-posterior) were significant between them, i.e., the body sway was smaller in gum chewing than in the rest position of mandible. Since similar tendency was also seen by the analysis of body sway in the habitual chewing side test, it was likely that there was no influence due to the chewing side of each subject. When the distribution of foot bottom pressure was estimated on the basis of these results, the number of points at which foot bottom pressure was detected was larger in left-right gum chewing test than in the rest position of mandibule test. And the magnitnde of the pressure was also larger in the former. Thus, it was indicated that the distribution of foot bottom pressure was much changed by gum chewing. The present results suggest that the subjects kept balance on foot bottom adapting to the mandibular movements for gum chewing and also head position changes associated with the movement. In addition, the foot bottom pressure during loading of mouth guard was measured. A custom-made mouth guard type 4, specified by ADA was applied to the subjects. The results showed that there was no significant difference in body sway between the rest position of mandibule and the time of mouth guard loading. Therefore, mouth guard loading was concluded to have little effects on body sway Less