三种相变点正畸镍钛合金弓丝的力学性能比较

目的:研究不同相变点(A f值)正畸镍钛合金弓丝的性能,探讨其性能与相变点之间的关系。方法:对3种不同相变点的正畸镍钛合金圆丝(0.016″),在相同口腔温度(37℃)和形变速度及不同形变量下,利用三点弯曲实验测量应力应变曲线得到正畸力,测量弓丝的相变点。结果:在形变量3.0 mm时,相变点最高的镍钛弓丝产生的正畸力最小,反之相变点最低的正畸力最大。在小量形变范围内弓丝产生的正畸力无明显差异(P>0.05),但是超过0.5 mm后就出现了明显的差异(P<0.05),结果同形变量为3.0 mm时。结论:相变点温度高的3M un it和浙江大学材化学院提供的镍钛合金弓丝产生的正畸力相对较小、较稳定,其性能较好。

Comparison of mechanical properties on different phase transformation points of nickel-titanium orthodontic wires

OBJECTIVE: To compare the mechanical properties of different phase transformation of nickel-titanium orthodontic archwires. METHODS: Nickel-titanium orthodontic archwires with same-sized (0.016") but different phase transformation were examined using a three-point bend test.Samples were tested at same conditions and oral temperature(37 degree), but in different utmost strain capacity, then the strain-stress chart was obtained, the phase transformation point (Af) was also examined. RESULT: The wires of the highest phase transformation point had the least orthodontic force; on the contrast the least phase transformation point had the highest orthodontic force at 3.0 mm utmost strain capacity. The orthodontic forces were not different at the little strain capacity (P >0.05), but which was significantly different adove the 0.5 mm (P<0.05), which was same as 3.0 mm. CONCLUSION: The nickel-titanium orthodontic archwires with high level of phase transformation have low orthodontic forces and more stability.