目的：研究多用唇弓和摇椅弓作用下各牙位所受应力情况。方法：建立下颌骨、下牙列、下颌牙方丝弓托槽及弓丝的有限元模型，通过 ANSYS 分析多用唇弓和摇椅弓不同应用方法下各牙位的受力情况。结果：多用唇弓入槽后，切牙受龈向力，磨牙受向力；并随着多用唇弓丝给尖牙施以龈向力，切牙所受龈向力减小，第一磨牙所受向力增加。摇椅弓随着入槽牙位的增加，切牙受龈向力继续增加，尖牙受向力并逐渐增加，第二前磨牙受向力，第一磨牙受力方向由向转为龈向。结论：多用唇弓对尖牙施加龈向力时，侧切牙受力显著减小，应在切牙压低完成后，单独完成尖牙的压低过程。摇椅弓入槽方式不同对各牙位所产生的应力大小和方向都有所不同，并且随着入槽牙位的增加，侧切牙和磨牙受力改变最为明显。%Objective:To study the force system of teeth produced by utility arch and rocking-chair arch for the treatment of deep o-verbite.Methods:Finite element model of mandible,mandible teeth,edgewise brackets and arch was established,utility arch and rocking chair arch were applied respectively,the force direction and magnitude of molars and incisors was analyzed by ANSYS.Re-sults:When utility arch was used,incisors bear intrusive force and molars bear extrusive force.With the utility arch wire was giving intrusive force to canine,the intrusive force to incisors reduced,the extrusive force to the first molars increased.When adding the bracketed teeth,the intrusive force to incisors increased,but the extrusive force to the canines and the force direction of the molars changed.Conclusion:While the utility arch exerts intrusive pressing force to the canines,the intrusive force to the lateral incisors de-crease,therefore,pressing of canines shall be independently completed after completing pressing of incisors.Different application methods of rocking-chair arches will produce different force to teeth.With addition of teeth applied with rocking-chair arch,the force to lateral incisors and molars changes the most.
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