Abstract:

Objective    To observe the change of the surface structure of the arch wire due to different orthodontic bracket designs and ligations. Methods    In the dry environment the sliding of bracket  on the arch wire was simulated，and WDW20 & 0.5 electronic universal testing machine was used to provide uniform traction；the arch wire was scanned with SEM. Results    The wires investigated in this study had varying degrees of change；the MLF bracket with 0.2 mm ligation group had minimal changes to the arch wire surface. The scratches of arch wire surface distributed evenly on elastic ligation ring group；0.25 mm ligature wire was likely to cause the uneven distribution of stress. Conclusion    The different ways of ligation have different effects on morphological structure of the surface of the arch wire. The coarser ligature wires have bigger influence on the arch wire surface structure. Different orthodontic bracket designs will change the arch wire surface structure.

Key words: friction, scanning electron microscope, surface, in vitro, stainless steel orthodontic wire

摘要：

目的    观察不同托槽设计及结扎方式对弓丝表面结构的改变。方法    选用MBT、MLF和传动直丝弓等3种国产不锈钢托槽，分别使用弹力结扎圈、0.20 mm结扎丝和0.25 mm结扎丝结扎。干燥环境中模拟托槽在弓丝上滑动，使用WDW20&0.5电子式万能试验机提供匀速牵引，再对弓丝进行电镜扫描。结果    正畸弓丝在模拟滑动后，表面结构均发生不同程度的改变，其中MLF托槽搭配0.20 mm结扎丝组弓丝表面改变最小；弹力结扎圈结扎时弓丝表面划痕分布均匀；0.25 mm结扎丝易造成应力分布不均。结论    不同结扎方式对弓丝表面形态结构影响不同，较粗结扎丝对弓丝表面结构影响较大，不同托槽设计会改变弓丝表面结构。

关键词: 摩擦力, 电镜扫描, 表面结构, 体外实验, 不锈钢弓丝