A new esthetic fiber-reinforced polymer composite resin archwire: a comparative atomic force microscope (AFM) and field-emission scanning electron microscope (FESEM) study

BACKGROUND Fiber-reinforced polymer composite (FRPC) archwires could provide an esthetic solution to conventional orthodontic archwires. This study was carried out with the following aims: (1) to compare the sliding friction of FRPC archwire with nickel titanium archwire using various archwire-bracket combinations and (2) to determine the correlation between surface roughness and friction of the FRPC and NiTi archwires. METHODS Four different brackets (Gemini® (Gemini-3M Unitek, St. Paul, MN, USA), ICE® (ICE-Ormco- Orange, CA, USA), Clarity® (Clarity-3M Unitek, St. Paul, MN, USA), and SmartClip® (SmartClip-3M Unitek, St. Paul, MN, USA)) in combination with FRPC wires and NiTi wires (0.018 in) were studied for archwire friction with simulated wear and surface roughness using scanning electron microscope (SEM) and atomic force microscope (AFM), respectively. Statistical analysis of frictional wear generated and surface roughness between the various archwire and bracket groups was evaluated by one-way ANOVA at 5% level. Least significant difference (LSD) multiple comparisons were used to determine the archwire-bracket group difference. RESULTS Gemini®-FRPC group generated the highest frictional wear (mean, 313.10; SD, 802.59) and ICE®-FRPC group produced the highest roughness values among all the groups tested (Ra = 496.13 nm, RMS = 635.49 nm). No correlation was found between frictional wear and surface roughness of the archwires of the various groups. CONCLUSIONS FRPC archwire shows promise in its application as an esthetic aligning archwire. However, further research and refinement in its manufacture would be necessary to fully realize its potential as an esthetic archwire.