Tanne K, Inoue Y, Sakuda M
Department of Orthodontics, Hiroshima University School of Dentistry, Japan.
Angle Orthod. 1995;65(2):123-8. doi: 10.1043/0003-3219(1995)065<0123:BBOTPB>2.0.CO;2.
This study was designed to investigate the biomechanical behavior of the periodontium including the periodontal ligament (PDL) in terms of tooth mobility. Tooth mobility was measured in the canines of 10 adolescent patients before and after distal movement. Distal movement of the canines was carried out by use of a calibrated sectional archwire exerting an initial retraction force of 200 g. Tooth mobility was measured immediately before and after canine retraction by use of a noncontact displacement sensor when varying distal forces of 0 to 500 g were applied to the mesial of the canine. Before tooth movement, tooth mobility exhibited a substantial increase in loading with forces ranging from 50 to 150 g. The rate of increase gradually decreased up to 500 g. A nonlinear change in tooth mobility was similarly observed at the end of tooth movement or 24 days after the initiation of movement. Tooth mobility, however, was significantly greater when forces above 200 g were loaded. The periodontal tissues--the PDL and alveolar bone in particular--become more flexible at the end of tooth movement, indicating reduced support by the periodontal tissues. These findings suggest that the elastic nature of the PDL and alveolar bone may decrease substantially at the end of tooth movement.
本研究旨在从牙齿移动性方面调查牙周组织（包括牙周韧带，PDL）的生物力学行为。在10名青少年患者的犬齿远中移动前后测量其牙齿移动性。犬齿的远中移动通过使用施加200g初始回缩力的校准分段弓丝来进行。当向犬齿近中施加0至500g的不同远中力时，在犬齿回缩前后立即使用非接触式位移传感器测量牙齿移动性。在牙齿移动前，当施加50至150g的力时，牙齿移动性随负荷显著增加。增加速率逐渐降低，直至500g。在牙齿移动结束时或移动开始后24天，同样观察到牙齿移动性的非线性变化。然而，当施加超过200g的力时，牙齿移动性显著更大。牙周组织，尤其是PDL和牙槽骨，在牙齿移动结束时变得更具柔韧性，表明牙周组织的支持作用减弱。这些发现表明，在牙齿移动结束时，PDL和牙槽骨的弹性性质可能会大幅下降。
