| 摘要 |
A screw device for orthodontic treatment comprises a screw-body part, a platform part integrally formed with the screw-body part, and a head part. The head part is detachable from and exposed outside the screw-body part and is operatable to hook a spring (or rubber band) for orthodontic treatment. Since the head part is detachable, various types of head parts can be chosen to attach on the same platform part and screw-body part for performing different orthodontic treatments. Cost to manufacture the screw device is lower, and flexibility and convenience to use the screw device are higher. The external threads of the screw-body part are slightly loosened and tapered at a portion away from the platform part and relatively concentrated at another portion near to the platform part.
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