Abstract: 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.

Abstract: 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.

Abstract: A long-armed type molar uprighting spring is disclosed. It contains: (a) a lingual groove rest for mounting the uprighting spring in a lingual groove of a first molar; (b) a loop, which extends from the lingual groove and can be fixedly mounted around a mesial side of a second molar; (c) a buccal bracket rest extending from one end of the loop opposing the lingual groove rest for resting the upright spring on a buccal bracket of the first molar; (d) a reactivating area, which extends from the other end of the buccal bracket rest to fit into an area between the first molar and a second premolar so as to provide a stronger activating function; (e) a lever arm, which extends from the reactivating area to provide an uprighting function in accordance with impacted condition of the second molar. The long-armed type uprighting spring is specially designed in accordance with a first kind lever theory so as to overcome the problem of poor bonding that may affect a molar.