Abstract:
Aim: To evaluate the changes in surface roughness and frictional features of ‘ion-implanted
nickel titanium (NiTi) and titanium molybdenum alloy (TMA) arch wires’ from its conventional
types in an in-vitro laboratory set up.
Materials and Methods: ‘Ion-implanted NiTi and low friction TMA arch wires’ were assessed
for surface roughness with scanning electron microscopy (SEM) and 3 dimensional (3D) optical
profilometry. Frictional forces were studied in a universal testing machine. Surface roughness
of arch wires were determined as Root Mean Square (RMS) values in nanometers and Frictional
Forces (FF) in grams.
Statistical Analysis Used: Mean values of RMS and FF were compared by Student’s ‘t’ test and
one way analysis of variance (ANOVA).
Results: SEM images showed a smooth topography for ion-implanted versions. 3D optical
profilometry demonstrated reduction of RMS values by 58.43% for ion-implanted NiTi (795.95
to 330.87 nm) and 48.90% for TMA groups (463.28 to 236.35 nm) from controls. Nonetheless,
the corresponding decrease in FF was only 29.18% for NiTi and 22.04% for TMA, suggesting
partial correction of surface roughness and disproportionate reduction in frictional forces with
ion-implantation. Though the reductions were highly significant at P < 0.001, relations between
surface roughness and frictional forces remained non conclusive even after ion-implantation.
Conclusion: The study proved that ion-implantation can significantly reduce the surface
roughness of NiTi and TMA wires but could not make a similar reduction in frictional forces.
This can be attributed to the inherent differences in stiffness and surface reactivity of NiTi
and TMA wires when used in combination with stainless steel brackets, which needs further
investigations.
