直流电热处理改变镍钛合金唇弓宽度的研究

目的评价直流电热处理方法对镍钛合金丝唇弓宽度的影响。方法选取8种镍钛方丝（0.016×0.022″）,采用加热仪分别对弓丝进行1s、1.5s、2s、2.5s的直流电热处理,加热后分别测量弓丝末端宽度变化,然后用SPSS10.0统计软件进行单因素方差分析。结果所有镍钛合金丝在加热1s后,唇弓宽度无显著变化,加热1.5s以后,唇弓宽度发生显著性改变,加热2s后,唇弓宽度变化最显著。结论镍钛合金丝的形状可以通过直流电热处理重新定型,临床可通过该方法调节镍钛合金丝的形态并弯制各种曲,但在热处理过程中,应注意电流大小的选择及加热时间的控制。

Effect of direct electric resistance heat treatment on the arch form of nickel-titanium orthodontic wires

Objective To investigate the effect of direct electric resistance heat treatment(DERHT) on the arch form of nickel-titanium orthodontic wires.Methods Eight kinds of nickel-titanium archwires (0.016×0.022) were reshaped using the DERHT method by a controlled electric current and different length of time (1.0,1.5,2.0,2.5 seconds).After the heat treatment,the width of each wire was measured.The data was statistically analyzed by one-way ANOVA.Results All wires width did not show significant change within the first second of treatment,but became wider after being heated for 1.5 seconds.When heated for 2 seconds,the wires width showed significant changes.Conclusion With the DERHT method,it is possible to reshape the arch form and bend Ni-Ti wires,but the amperage and the time should be under control.