Development and basic research onthe friction free orthodontic brackets

本研究的目的是开发和测试一种新的正畸托架设计，它可以充分控制牙齿的三维空间，同时将托架和弓丝之间的摩擦减少到最小程度。新型无摩擦支架具有独特的形状，其中圆柱或球形轴主要用于控制摩擦问题，而不牺牲控制扭矩的能力。研究了新支架和钢丝的应力-应变特性，以及轴与钢丝之间的滑动阻力。由于新支架的独特设计，摩擦力大大降低。当托架的表面设计从平面变为直线，然后变为点时，摩擦逐渐减少。采用无摩擦托架，与传统托架系统相比，可缩短正畸治疗周期。使用较轻的正畸力可减少牙根吸收和患者的不适。除了金属支架外，还研究了聚二甲基丙烯酸酯制成的新型隐形支架材料。试验研究表明，聚二甲基丙烯酸酯制成的托槽具有增强托轴强度和美容效果的主要优点，可以成功地应用于正畸临床。

The purpose of the present studyis to develop and test a new orthodontic bracket design which allows adequate three dimensional control of the teeth yetreduces the frictin between bracket andarch wire to a minimum degree.The new friction free bracket has a unique shape, in which cylindric or spherical shafts are mainly designed to control the problem of friction, without sacrificing the ability to control torque.The study examined the stress-strain properties of the new brackets andwire, and the resisitance of slide between the shafts and the wire1.Triction force substantially reduced due to the unique design of the new brackets. Friction gradually reduced as the surface design of the brackets changed from a plane, to a line, and then to a point2.By the friction-free brackets, orthodontic treatment term will be shortenes compared to the conventional type bracket system. Root resorption and the patient discomfort will be reduced by use of lighter orthodontic forces.3.New material for invisible bracket made of polydimethacrylate is also studied beside the metal brackets. The test study showed that the bracket made of polydimethacrylate could be successfully used in the orthodontic clinic with the major advantages of the bracket characterized by enhanced strangth of the shafts as well as cosmetic effects.