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In vitro evaluation of the influence of velocity on sliding resistance of stainless steel arch wires in a self‐ligating orthodontic bracket
Author(s) -
Savoldi F.,
Visconti L.,
Dalessandri D.,
Bonetti S.,
Tsoi J. K. H.,
Matinlinna J. P.,
Paganelli C.
Publication year - 2017
Publication title -
orthodontics and craniofacial research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 55
eISSN - 1601-6343
pISSN - 1601-6335
DOI - 10.1111/ocr.12156
Subject(s) - bracket , arch , materials science , orthodontics , nickel titanium , mathematics , composite material , structural engineering , shape memory alloy , medicine , engineering
Structured Abstract Introduction Of the variables used by in vitro studies of resistance to sliding ( RS ) in orthodontics, sliding velocity ( SV ) of the wire is often the one farthest from its clinical counterpart. We investigated whether velocity influences the RS at values approximating the orthodontic movement. Methods A SS self‐ligating bracket with a NiTi clip was fixed onto a custom‐made model. Different shaped orthodontic SS wires of four sizes and two types (round, 0.020″ and 0.022″; rectangular, 0.016″×0.022″ and 0.017″×0.025″) were tested using an Instron ® testing machine. Wires were pulled at four velocities (1×10 −2 mm/s, 1×10 −3 mm/s, 1×10 −4 mm/s, 1×10 −5 mm/s). Shapiro‐Wilk test was used to evaluate the normal distribution of the data; two‐way ANOVA was performed to compare means in the RS with wire characteristics and SV . Significance level was set at P <.05. Results RS was higher for rectangular wires, and for those with larger diameters. Lower SV was associated with lower RS , with wire type and size having an interaction effect. The RS relatively to SV can be represented as: RS ∝ α[ln( SV )]+β, where α and β are constants. Conclusions At very low SV and low normal forces, SV influences the RS of SS archwires in orthodontic brackets, and the proportionality is logarithmic. Although respecting these parameters in vitro is challenging, quantitative evaluations of RS should be carried out at clinically relevant velocities if aiming at translational application in the clinical scenario.