复合矫治弓丝用于正畸拔牙矫治的三维有限元研究

目的通过建立三维有限元模型分析正畸拔牙矫治时复合矫治弓丝（compositearehwire，CoAW）的力学性能，探讨CoAW的应用选优问题。方法通过螺旋CT扫描，利用SOUDWORKS2001PLUS软件重建下颌骨三维有限元模型，模拟拔除两侧第一前磨牙矫治，在ANSYS软件中建立3种镍钛圆丝（直径为0．30mm、0．36mm、0．41mm）、2种不锈钢圆丝（直径为0．36mm、0．41mm）和6种CoAW（0．30mm、0．36imm、0．41mm直径的镍钛圆丝分别连接0．36mm、0.41mm直径的不锈钢圆丝）弓丝模型，进行力学加载与计算分析。结果当CoAW中镍钛段弓丝直径逐渐加大，而不锈钢丝段弓丝直径保持不变时，牙齿所受的应力逐渐增加。当CoAW中不锈钢丝段弓丝直径逐渐增大，而镍钛段弓丝直径保持不变时，牙齿所受的应力也逐渐增加。在6种组合的CoAW中，以CoAW（0．30mm直径的镍钛圆丝连接0．36mm直径的不锈钢圆丝）对牙齿产生的应力最小。对于支抗后牙的应力大小，6种组合的CoAW与不锈钢丝比较未见明显区别。结论CoAW中镍钛段与不锈钢丝段弓丝的直径与牙齿所受的应力大小密切相关。

A three-dimensional finite element study on composite archwire applied in extraction cases

OBJECTIVE: To explore mechanical properties of the composite archwire (CoAW) applied in extraction cases. METHODS: The mandibular three dimensional model was established by spiral computed tomography scanning and SOLIDWORKS 2001PLUS software. The archwire model was established by means of ANSYS software. The mechanical analysis and calculation of CoAW were carried out. RESULTS: With the diameter of NiTi part of CoAW gradually augmented (the diameter of stainless steel part kept unchanged), the stress on teeth gradually increased. As the diameter of stainless steel part of CoAW gradually augmented (the diameter of NiTi part kept unchanged), the stress on teeth also gradually increased. The CoAW (0.30 mm NiTi round wire combined with 0.36 mm stainless steel round wire) produced the least force on teeth. There was little contradistinction between six kinds of CoAW and stainless steel wire on the stress of posterior teeth. CONCLUSIONS: The stress on teeth closely correlated with the diameter of the composite archwire.