In vitro force delivery of nickel-titanium superelastic archwires in vertical displacement

Aisha de Souza Gomes STUMPF, Karina dos Santos MUNDSTOCK, Daniel MUNDSTOCK, Carlos Alberto MUNDSTOCK

Objective: The purpose of this study was to evaluate the force delivered by different superlastic nickel-titanium wires during vertical displacement, in order to determine whether their stress release meets the criteria for constant and light forces that are usually accredited to these archwires. Method: Ten samples of 6 brands of 0.016-in archwires (Ormco, GAC, Morelli, TP, American Orthodontics e Rocky Mountain) were tested in a complete metal model using Dynalock brackets (3M Unitek™). In the canine position, there was a sliding bracket connected to a pole. This set was related to a load cell of 0.5 kg attached to a universal testing machine (Autograph AG-199kNG, Shimadzu). The crosshead speed was 0.5 mm/min and the maximum displacement was 1.0 mm. The model was submerged in temperature-controlled water. The results were analyzed by ANOVA (p < 0.05), using the software SAS System 8.02, Cry, NC, USA. Results: The TP archwire had the lowest force throughout the test, although the final force was high (277.91 g). The Rocky Mountain archwire had the highest force release (455.41 g). Conclusion: The different brands of wires tested in this study failed in delivering low and constant forces as expected from superlastic nickel-titanium wires. The forces were extremely heavy for a vertical tooth movement.

Keywords: Corrective orthodontics. Orthodontic archwires. Tooth movement.

How to cite: Stumpf ASG, Mundstock KS, Mundstock D, Mundstock CA. In vitro force delivery of nickel-titanium superelastic archwires in vertical displacement. Dental Press J Orthod. 2012 Nov-Dec;17(6):26-30.

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