座位の安定性が健常若年者の咬合機能に及ぼす影響

Influence of the stability of seated posture on the healthy youth's occlusal function

　座位安定性が咬合機能に及ぼす影響を明らかにするために，咬合バランス，咬合面積，咬合力，平均圧，最大圧を測定し検討した．対象は健常若年者10名とした．姿勢は安定座位と不安定座位の2種類とし，安定座位時の咬合バランスから咬合良好群と咬合やや不良群に分け，咬合良好群-安定，咬合良好群-不安定，咬合やや不良群-安定，咬合やや不良群-不安定の4群間で比較した．

　咬合バランスは咬合やや不良群で不安定座位時に悪くなりやすく，咬合面積は咬合良好群-不安定が咬合やや不良群-安定や，咬合やや不良群-不安定より有意に大きく(p＜0.05)，咬合力は咬合良好群-不安定が咬合やや不良群-安定より有意に大きかった(p＜0.05)．平均圧，最大圧は有意差がなかった．

　咬合・咀嚼機能を有効に発揮させるために，座位の安定性を高める必要があると考えられた．

　The purpose of this study is to clarify the influence of the stability of seated posture on occlusal function. Occlusal balance, area of occlusal contact, occlusal force, average pressure, and the maximum pressure were measured. Participants were ten healthy youths. Two kinds of posture were set up;a stable seated posture and an unstable seated posture using a balance board. The subjects were divided into two groups according to their occlusal balance during the stable seated posture condition;the good occlusion group, and the poor occlusion group. The data of the two occlusion groups were analyzed and compared for the two posture conditions. The occlusal balance worsened easily in the poor occlusion group with the unstable seated posture. The area of occlusal contact of the good occlusion group during the unstable condition was significantly larger compared with the poor occlusion group in both stability conditions (p＜0.05). The occlusal force of the good occlusion group during the unstable condition was significantly stronger than the poor occlusion group during the stable condition (p＜0.05). No significant difference was found for the average pressure or the maximum pressure among the four groups. In order to demonstrate occlusal and masticatory functions effectively, it is necessary to stabilize the seated posture.