Kuhlberg Andrew J, Priebe Derek
Department of Orthodontics, School of Dental Medicine, University of Connecticut, 263 Farmington Avenue, Farmington, CT 06030-1725, USA.
Angle Orthod. 2003 Jun;73(3):270-80. doi: 10.1043/0003-3219(2003)073<0270:TFSABT>2.0.CO;2.
Orthodontic tooth movement can be compared to a stimulus-response model, where the stimulus is the applied force system and the response is the resulting tooth movement. Although the principles of mechanics have been applied to orthodontic appliance design, the expression of treatment responses to the force systems is less well known. The purpose of this study was to compare measured tooth movements with the theoretical force system exerted by differential moment closing loops. Sixteen subjects requiring maximum posterior anchorage control were selected to participate in this prospective investigation. T-loop springs designed to deliver a differential moment-to-force ratio to the posterior vs the anterior teeth were used. Initial cephalometric radiographs were taken with special devices attached to the molar and canine teeth to allow precise identification. Immediately after the radiograph, the T-loop archwires were inserted and activated. After an observation period of approximately 90 days, the wires were removed, devices reinserted into the molars and canines, and a second cephalometric radiograph was obtained. Superimposition techniques were used to compare the actual tooth movements. The results showed tooth movements consistent with the prescribed force system. The anterior teeth, as represented by the canines, were retracted an average of 1.73 mm, whereas the posterior anchorage (molars) moved mesially only 0.50 mm. Furthermore, the canine teeth exhibited tipping or translation, and the molars showed mesial root movement. The variability of the treatment response as a function of the stimulus (appliance design), response (biological variation), and measurement technique was described.
正畸牙齿移动可以与刺激-反应模型相比较，其中刺激是施加的力系统，反应是由此产生的牙齿移动。尽管力学原理已应用于正畸矫治器设计，但对力系统的治疗反应的表现却鲜为人知。本研究的目的是将测量的牙齿移动与差动矩闭合环施加的理论力系统进行比较。选择16名需要最大程度控制后牙支抗的受试者参与这项前瞻性研究。使用设计为向后牙与前牙传递差动矩-力比的T形环弹簧。使用附着在磨牙和尖牙上的特殊装置拍摄初始头影测量X线片，以便精确识别。在拍摄X线片后，立即插入并激活T形环弓丝。经过约90天的观察期后，取出弓丝，将装置重新插入磨牙和尖牙，并获得第二张头影测量X线片。使用叠加技术比较实际的牙齿移动。结果显示牙齿移动与规定的力系统一致。以尖牙为代表的前牙平均后移1.73mm，而后牙支抗（磨牙）仅向近中移动0.50mm。此外，尖牙表现出倾斜或平移，磨牙表现出近中牙根移动。描述了作为刺激（矫治器设计）、反应（生物变异）和测量技术函数的治疗反应的变异性。
