时效对正畸弓丝摩擦力影响的实验研究

Effects of oral conditions on the surface frictional forces of stainless steel wires

目的探讨不锈钢丝在口内使用一段时间后其摩擦力所受到的影响。方法用0.018英寸的国产不锈钢圆丝、0.018英寸进口的不锈钢圆丝、0.019×0.025英寸进口不锈钢方丝分别在口内使用4周、8周、12周、16周、20周(n=20)。取尖牙远中与磨牙近中之间的弓丝,检测其摩擦系数并与新弓丝做比较。结果与新弓丝相比,使用过的进口不锈钢圆丝、进口不锈钢方丝摩擦力无明显变化,而国产的圆丝使用3个月后摩擦力变大。结论就摩擦力而言进口不锈钢丝在口内的使用周期较长。

Objective To investigate the changes in frictional forces of various used SS (stainless steel) wires. Methods Two types of SS round wires (0.018') and one type of SS rectangular wires (0.019×0.025) were divided into 6 groups respectively: subjected to conditions (T0, control group), exposed to oral conditions for 4 weeks (T1), 8 weeks (T2), 12 weeks(T3), 16 weeks(T4) and 20 weeks(T5). Frictional coefficients were tested by friction test. Results Our findings showed that there were no statistically significant differences among wires of the three types, the new wires and the used rectangular wires as well as one of the round wires were in frictional forces. They also demonstrated that the other one of the round wires had significantly greater frictional coefficients than the control wires when exposed to oral conditions for 12 weeks to 20 weeks (P <0.05). Conclusion Used in the oral cavity for 5 months, the frictional forces of some types of SS wires could not be affected.