Resumen de A randomized clinical trial investigating pain associated with superelastic nickel�titanium and multistranded stainless steel archwires during the initial leveling and aligning phase of orthodontic treatment
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 value?=?2.65, degrees of freedom (df)?=?92.6; P?=?0.1071]. However, compared to multistranded stainless steel wires, pain in subjects with superelastic nickel�titanium archwires was significantly greater at 12 h (t?=?2.34; P?=?0.0193), as well as at day 1 in the morning (t?=?2.21, P?=?0.0273), afternoon (t?=?2.11, P?=?0.0346) and at bedtime (t?=?2.03, P?=?0.042).
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.
