Objectives: comparing the effectiveness of laser-engineered copper-nickel titanium (SmartArch) to superelastic nickel-titanium (SENT) archwires in aligning teeth, inducing root resorption, and patient's experience of pain.
Methods: two-arm parallel groups with a 1:1 allocation ratio. The participants were patients aged 11.5 years and above with 5-9 mm of mandibular anterior crowding, who were indicated for non-extraction treatment. The primary outcome was alignment effectiveness assessed using Little’s irregularity index (LII) over 16 weeks with a single wire (0.016 inches) in the SmartArch group, and two wires (0.014 and 0.018 inches) in the SENT group (eight weeks each). Secondary outcomes included root resorption evaluated by pre- and post-intervention periapical radiographs, and pain levels recorded by participants during the first week.
Results: A total of 40 participants were randomly allocated into two groups, 33 participants completed the study and were analysed (16 in the SmartArch group and 17 in the SENT group, aged 16.97 ± 4.05 years). The total LII decrease for the SmartArch and SENT groups was 5.63 mm and 5.29 mm respectively, which was neither statistically nor clinically significant. Root resorption was non-significant between groups. The difference in pain levels was not statistically significant for the first five days following wire placement; however, there was a significant difference favouring the SENT group in the final two days.
Conclusions: SmartArch and SENT archwires were similarly effective during the alignment phase of orthodontic treatment. Root resorption should be observed throughout treatment with either wire. SmartArch wires demonstrated a higher pain perception than SENT wires.

Keywords: Randomized clinical trial, Aligning archwires, Alignment