Heat-Activated NiTi Archwires Eased Pain but Did Not Speed Overall Alignment in Trial

Edited by Orthotown staff

Heat-activated nickel-titanium archwires produced faster early alignment and lower pain than conventional nickel-titanium wires, but the overall six-month alignment rate did not differ significantly, according to a randomized controlled trial published online Oct. 17 in the Journal of Orthodontics.

The two-arm parallel trial compared the two archwire sequences for maxillary anterior alignment in patients who needed fixed orthodontic treatment with first premolar extractions. All had a Little’s Irregularity Index of 7–9 mm. Of 46 participants randomized, 44 completed the trial, 22 in each group.

Investigators measured irregularity on digital scans taken at baseline and monthly for six months. Both groups improved significantly. A significant time-by-group interaction (P = .035) reflected greater irregularity reduction with heat-activated wires between months one and three.

Across the full six months, the heat-activated group aligned at 1.35 mm per month and the conventional group at 1.30 mm per month, a difference that was not statistically significant.

Pain, rated on a visual analog scale at 24 hours and three and seven days after activation, was lower with heat-activated wires. Cone beam computed tomography before and after alignment showed no between-group differences in root length or alveolar bone changes.

The trial was conducted by Khanh Vu Phuong Le, Lam Nguyen Le, and Ngan Thi Bich Truong of Can Tho University of Medicine and Pharmacy in Vietnam and was registered at ClinicalTrials.gov (NCT07176871).

The authors said the differences between the wires were small and may be of limited clinical significance. They also said further research is needed to determine whether the early gains translate into shorter overall treatment.

Sources:
Journal of Orthodontics, “Heat-activated nickel-titanium versus conventional nickel-titanium archwire sequences for maxillary anterior alignment: A randomised controlled trial,” published online Oct. 17, 2026: journals.sagepub.com/doi/10.1177/14653125261493138
PubMed, PMID 42888967: pubmed.ncbi.nlm.nih.gov/42888967