| 摘要 |
A long-arm type upright molar tooth spring includes a lingual groove rest, for resting the spring at a lingual groove of a first molar tooth; a loop, for surrounding and fixing the periphery of the second molar tooth; a buccal bracket rest, for resting the spring at a buccal bracket of the first molar tooth; a reactivating area, being an area between the first molar tooth and the second premolar tooth; a lever, for applying a force onto the second molar tooth; and an arc, extended from an adjacent wall between an engaging surface of the first molar tooth and an engaging surface of the second molar tooth, and fixed at a root of the second molar tooth.
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