Arandomized clinical trial investigating pain associated with superelastic nickel-titanium and multistranded stainless steel archwires during the initial leveling and aligning phase of orthodontic treatment

Abstract

Objective: To investigate and compare the effects of superelastic nickel-titanium and multistranded stainless steel archwires on pain during the initial phase of orthodontic treatment. Design: A double-blind two-arm parallel design stratified randomized clinical trial. Setting: A single centre in India between December 2010 and June 2012. A total of 96 participants (48 male and 48 females; 14.1-2.1 years old) were randomized (stratified on age, sex and initial crowding) to superelastic nickel-titanium or multistranded stainless steel archwire groups using a computer-generated allocation sequence. Methods: We compared 0.016-inch superelastic nickel-titanium and 0.0175-inch multistranded stainless steel wires in 0.022- inch slot (Roth prescription) preadjusted edgewise appliances. The follow-up period was 14 days. Outcome was assessed with a visual analogue scale at baseline and 32 pre-specified follow-up points. Data was analyzed using mixed-effects model analysis. Results: One participant was lost to follow up and 10 were excluded from the analysis due to bond failure or incomplete questionnaire answers. Ultimately, 85 participants (42 males and 43 females; 14.1-2.0 years old) were analysed for the final results. No statistically significant difference was found for overall pain [F value52.65, degrees of freedom (df)592.6; P50.1071]. However, compared to multistranded stainless steel wires, pain in subjects with superelastic nickel-titanium archwires was significantly greater at 12 h (t52.34; P50.0193), as well as at day 1 in the morning (t52.21, P50.0273), afternoon (t52.11, P50.0346) and at bedtime (t52.03, P50.042). Conclusion: For overall pain, there was no statistically significant difference between the two wires. However, subjects with superelastic nickel-titanium archwires had a significantly higher pain at peak level. © 2013 British Orthodontic Society.