Surface Characteristics of New and Retrieved Copper NiTi Archwires of Two Passive Self Ligating Systems
Author(s): Anjali Anna Thomas*, Harish Babu
Introduction: Surface characteristics of orthodontic archwires play a major role in determining their coefficient of friction.
Surface character of an arch wire is inherent to an alloy used and the manufacturing process and surface treatment of the
arch wire. Friction characters of an arch wire are an important factor when the archwire is used in passive self ligating
brackets while aligning crowded and collapsed arch forms.
Aim: The aim of the present study was to evaluate the surface characteristics of new and retrieved CuNiTi archwires of two
passive self-ligating brackets.
Materials and methods: This in vivo study consisted of 4 groups, each group containing 10 archwire samples. Group 1: as
received Tanzo CuNiTi; group 2: as received Damon CuNiTi; group 3: retrieved Tanzo CuNiTi; group 4: retrieved
Damon CuNiTi. Tanzo archwires were used along with AO passive self-ligating brackets, whereas the Damon archwires
were used with Damon passive self-ligating brackets. Only the 0.013 initial aligning archwires from the Tanzo and
Damon CuNiTi wires used in the study. The archwires used in vivo were retrieved after 12 weeks and were washed with
distilled water which were then wrapped in packs labelled with the patient’s names. The surface roughness of the
archwires in the four groups was tested using Atomic Force Microscopy in terms of Ra in μm.
Results: Tanzo CuNiTi showed comparatively lesser surface roughness than that of Damon CuNiTi. But statistically there
was no significant difference (p=>0.05). When comparing group 3 and group 4, it showed statistically significant difference
(p=<0.05) in the mean surface roughness of the archwires in the two groups; with retrieved Tanzo CuNiTi showing lesser
surface roughness than that of Damon CuNiTi.
Conclusion: Ra values (μm) of retrieved Tanzo CuNiTi are less than that of Damon CuNiTi. When comparing the surface
roughness of the as received Tanzo and Damon CuNiTi, the Ra (μm) values of Tanzo CuNiTi was less as compared to Damon
CuNiTi, but the difference was not statistically significant.