Pain After Archwire Placement With Three Types of Nickel-Titanium Archwires

Objectives: The objective of this prospective, triple-blinded, randomized controlled clinical trial was to compare the pain experience in patients receiving initial nickel-titanium (NiTi) archwires as part of their orthodontic treatment.
Methods: Immediately after braces were bonded to the teeth, 21 participants (7 each allocated to 3 groups with block randomization) received 0.016 inch round archwires that were either stabilized martensite (Nitinol from 3M Unitek), superelastic (27 degree Celsius Copper NiTi from Ormco) or thermoelastic (35 degree Celsius Copper NiTi from Ormco). Participants noted their pain levels on a visual analogue scale at 7 time points (baseline, 1 hour, 2 hours, 5 hours, 25 hours, 4 days and 7 days).
Results: ANOVA found that there were significant differences between the self-reported pain levels of groups at 2 and 5 hours; p=0.0234 and p=0.0053; respectively. Ranked comparisons found that patients who received superelastic NiTi reported significantly higher pain levels at 2 hours (p<0.05) than the other NiTi wires and higher than stabilized martensite at 5 hours (p<0.05) after archwire insertion. There were no other significant differences.
Conclusions: Superelastic NiTi archwires elicited significantly more pain than stabilized martensite or thermoelastic NiTi archwires in the first day after ligation of fixed orthodontic appliances.