Nattrass C, Ireland A J, Sherriff M
Department of Child Dental Health, Bristol Dental Hospital, U.K.
Br J Orthod. 1997 May;24(2):127-31. doi: 10.1093/ortho/24.2.127.
This in vitro investigation was designed to establish not only how clinicians apply forces for space closure when using the straight wire appliance and sliding mechanics, but also to quantify the initial force levels produced. A single typodont, with residual extraction space in each quadrant, was set up to simulate space closure using sliding mechanics. On two occasions, at least 2 months apart, 18 clinicians were asked to apply three force delivery systems to the typodont, in the manner in which they would apply it in a clinical situation. The three types of force delivery system investigated were elastomeric chain, an elastomeric module on a steel ligature, and a nickel-titanium closed coil spring. A choice of spaced or unspaced elastomeric chain produced by a single manufacturer was provided. The amount of stretch which was placed on each type of system was measured and, using an Instron Universal Testing Machine, the initial force which would be generated by each force delivery system was established. Clinicians were assessed to examine their consistency in the amount of stretch which each placed on the force delivery systems, their initial force application and their ability to apply equivalent forces with the different types of force delivery system. The clinicians were found to be consistent in their method of application of the force delivery systems and, therefore, their force application, as individuals, but there was a wide range of forces applied as a group. However, most clinicians applied very different forces when using different force delivery systems. When using the module on a ligature the greatest force was applied, whilst the nickel titanium coil springs provided the least force.
这项体外研究旨在不仅确定临床医生在使用直丝弓矫治器和滑动机制进行间隙关闭时如何施加力，还对产生的初始力水平进行量化。设置了一个单颌模型，每个象限有剩余拔牙间隙，以模拟使用滑动机制进行间隙关闭。在至少间隔2个月的两次实验中，邀请18名临床医生以他们在临床情况下的应用方式，对该单颌模型应用三种力传递系统。所研究的三种力传递系统分别是弹力链、钢丝结扎圈上的弹性模块和镍钛闭合螺旋弹簧。提供了由单一制造商生产的间隔或不间隔弹力链的选择。测量了每种系统的拉伸量，并使用英斯特朗万能试验机确定了每种力传递系统产生的初始力。评估临床医生在每种力传递系统上施加的拉伸量、他们的初始力施加以及使用不同类型力传递系统施加等效力量的能力方面的一致性。发现临床医生作为个体在力传递系统的应用方法以及因此他们的力施加方面是一致的，但作为一个群体施加的力范围很广。然而，大多数临床医生在使用不同的力传递系统时施加的力非常不同。使用结扎圈上的模块时施加的力最大，而镍钛螺旋弹簧提供的力最小。
