Alignment Efficacy and Transverse Dental Arch Changes with Different Initial Orthodontic Archwires

Alignment is the primary objective of the initial phase of fixed orthodontic treatment, requiring light and continuous forces for efficient tooth movement. Nickel-titanium based wires are the most widely used, with superelastic NiTi and thermoelastic CuNiTi being the most commonly selected in contemporary practice.

The aim of this review was to evaluate the existing clinical evidence on the alignment efficacy and transverse dental arch changes produced by superelastic NiTi and thermoelastic CuNiTi archwires in patients undergoing fixed orthodontic treatment.

A literature search was conducted in PubMed/MEDLINE and Google Scholar using relevant keywords related to NiTi and CuNiTi archwires, alignment efficacy, and transverse dental arch changes. Only studies published in English were included. Seven studies met the inclusion criteria and were included in the review.

All seven included studies reported effective crowding reduction with both wire types, with no statistically significant difference in alignment efficacy or time to alignment between groups. Evidence on transverse dental arch changes was limited to two studies with inconsistent findings. The severity of initial crowding was the only consistent predictor of alignment duration across all studies.

The available clinical evidence suggests that NiTi and CuNiTi archwires produce comparable alignment outcomes during the initial leveling stage of fixed orthodontic treatment. However, none of the included studies characterized the mechanical properties of the wires used clinically, making it impossible to establish a direct relationship between wire mechanical behavior and clinical outcomes, highlighting the need for future research integrating both approaches.