| 摘要 |
An orthodontic appliance for use in orthodontic therapy which comprises (a) a bracket (3) detachably secured to a patient's tooth (7), the bracket being made from a thermoplastic material e.g. a polysulphone, that has a low coefficient of friction, a tensile strength of 50-90 N/mm2, a mod. of elasticity of 2001-2600 N/mm2 and a notched impact strength of 40-80 J/n (at 2.8-15 mm) and (b) an arch (2) which can be used with the brackets and comprises a wire or ribbon of cold-drawn steel which is coated with a polyamide of 0.02-0.2 mm thickness. |
