Picton D C
Arch Oral Biol. 1986;31(6):369-72. doi: 10.1016/0003-9969(86)90159-7.
Extrusive mobility of 15 teeth in 4 adult macaques was compared with intrusive mobility of the same teeth. The character of the load displacement and recovery records was similar; the qualitative response to repeated 4 N thrusts, 4 N loads sustained for 30 s and residual loading with 50, 30 and 10 mN, was the same whether the force was applied in an intrusive or extrusive direction. Fast and slow loading rates (100 and 1 Ns-1) both caused greater intrusion than extrusion at 4 N (p less than 0.001). Thus the mechanisms of tooth support are similar for intrusive and extrusive force. The oblique orientation of the principal fibres of the ligament may allow a greater degree of initial intrusive movement, before tension is generated, than occurs in axially-aligned fibres under extrusive force. Extrusive loading may be a convenient method for studying tension in the periodontal ligament.
比较了4只成年猕猴中15颗牙齿的伸长移动与同一牙齿的压入移动。负载位移和恢复记录的特征相似；无论力是沿压入还是伸长方向施加，对重复4N推力、持续30s的4N负载以及50、30和10mN的残余负载的定性反应都是相同的。快速和慢速加载速率（100和1Ns-1）在4N时均导致压入大于伸长（p小于0.001）。因此，压入力和伸长力的牙齿支持机制相似。韧带主纤维的倾斜方向可能允许在产生张力之前比伸长力作用下轴向排列的纤维发生更大程度的初始压入移动。伸长加载可能是研究牙周膜张力的一种便捷方法。
