Force degradation of nickel-titanium closed coil springs: an in vitro
Keywords:Orthodontics; Movement; Spring coil; Nickel-titanium.
Objective: evaluation of the forces resulting from the initial stretching of closed Nickel-titanium springs and the degradation of these forces after 28 days of stretching. Methodology: The sample comprised 80 Morelli Nickel-titanium closed coil springs, divided into 4 groups of 20 according to their length, 7, 9, 12 and 15mm. In each group, 10 spring coils suffered distension in 50 and 100% of its original length and were maintained in devices to simulate the distension. The resulting forces were measured with a tensiometer and compared with the force described by the manufacturer on the spring packaging (200 grams force). Measurements were performed in 2 time-points; right after the initial strain (T1) and after 28 days (T2), when the devices were kept in artificial saliva at a temperature of 37°C. For the statistical analysis, the Mann-Whitney test was applied to compare the forces in T1 with the manufacturer's value and the paired t test to compare the forces between T1 and T2. In all statistical tests, a significance level of 5% was adopted. Result: In T1 the springs of 9, 12 and 15mm stretched by 50% showed significantly lower values and the springs of 7 and 15mm stretched by 100% showed significantly higher values, both compared with the manufacturer's recommendation. All groups of springs showed significant degradation of forces between T1 and T2, with percentage rates of force degradation from 7.1 to 21.9%. Conclusion: It is necessary to measure the forces of the springs during orthodontic treatment, aiming to establish an optimal force for tooth movement and thus optimizing the total treatment time.
Angolkar, P. V., et al. (1992). Force degradation of closed coil springs: an in vitro evaluation. Am J Orthod Dentofacial Orthop ,102,127-133.
Bezrouk, A., et al. (2014). Thermomechanical properties of nickel-titanium closed-coil springs and their implications for clinical practice. Am J Orthod Dentofacial Orthop , 146, 319-327.
Cox, C., et al. (2014). In-vivo force decay of nickel-titanium closed-coil springs. Am J Orthod Dentofacial Orthop , 145, 505-513.
Geng, H., et al. (2019). The effect of orthodontic clinical use on the mechanical characteristics of nickel-titanium closed-coil springs. J Int Med Res , 47, 803-814.
Han, S ., & Quick , D. C.(1993). Nickel-titanium spring properties in a simulated oral environment. Angle Orthod , 63:67-72.
Maganzini , A. L., Wong , A. M., & Ahmed, M. K. (2010). Forces of various nickel titanium closed coil springs. Angle Orthod , 80:182-187.
Manhartsberger, C., & Seidenbusch, W. (1996). Force delivery of Ni-Ti coil springs. Am J Orthod Dentofacial Orthop, 109:8-21.
Miura, F., Mogi , M., Ohura , Y., Karibe, M. (1988). The superelastic Japanese NiTi alloy wire for use in orthodontics. Part III. Studies on the Japanese NiTi alloy coil springs. Am J Orthod Dentofacial Orthop, 94: 89-96.
Mohammed, H., et al. (2018). Effectiveness of nickel-titanium springs vs elastomeric chains in orthodontic space closure: A systematic review and meta-analysis. Orthod Craniofac Res , 21:12-19.
Nattrass, C., Ireland, A. J ., & Sherriff, M. (1998). The effect of environmental factors on elastomeric chain and nickel titanium coil springs. Eur J Orthod , 20:169-176.
Nightingale, C ., & Jones, S.P. (2003). A clinical investigation of force delivery systems for orthodontic space closure. J Orthod , 30: 229-236.
Norman, N. H ., Worthington. H., & Chadwick, S. M. (2016). Nickel titanium springs versus stainless steel springs: A randomized clinical trial of two methods of space closure. J Orthod ,43:176-185.
Samuels, R. H ., Rudge, S. J., & Mair, L. H. (1998). A clinical study of space closure with nickel-titanium closed coil springs and an elastic module. Am J Orthod Dentofacial Orthop , 114:73-79.
Santos, A . C., Tortamano, A ., Naccarato , S .R ., Dominguez-Rodriguez, G. C., Vigorito, J.W. (2007). An in vitro comparison of the force decay generated by different commercially available elastomeric chains and NiTi closed coil springs. Braz Oral Res , 21(1):51-57.
Schneevoigt , R., et al. (1999). Laboratory analysis of superelastic NiTi compression springs. Med Eng Phys , 21:119-125.
Vidoni , G ., et al. (2010) . Combined aging effects of strain and thermocycling on unload deflection modes of nickel-titanium closed-coil springs: an in-vitro comparative study. Am J Orthod Dentofacial Orthop , 138:451-457.
von Fraunhofer, J. A ., Bonds, P. W., & Johnson, B. E. (1988) . Force generation by orthodontic coil springs. Angle Orthod , 63:145-148.
Wichelhaus , A., et al. (2010) . Mechanical behavior and clinical application of nickel-titanium closed-coil springs under different stress levels and mechanical loading cycles. Am J Orthod Dentofacial Orthop , 137,671-678.
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Copyright (c) 2020 Ana Claudia de Castro Ferreira Conti; Caroline de Vitto; Leonardo Filipe Conceição; Gregório Bonfim Dourado; Graziela Hernandes Volpato; Joel Ferreira Santiago Junior; Renata Rodrigues de Almeida-Pedrin
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