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ortho - the international C.E. magazine of orthodontics

I 07ortho 1_2014 C.E. article_ self-ligating systems I withapieceofrectangular0.019-inchby0.025-inch SSwirebeingusedasacalipertodampenanytorque or angular interference during the measuring of the forces (Fig. 1). This ensured that the wires used in the test could be passively inserted into the slots. ThecylinderswerepositionedinanEMICDL2000 (Tescsoftwareversion3.01/05)forload/unloadtrials. Each bracket was tested in three different steps: •M1–Moment1–(PullOut).Measurementofthe force that the clip exerts over the wire when pulled until the limit. • M2 – Moment 2 – (Load). Maintaining strength of a constant load of 20 N during a period of two hours. • M3 – Moment 3 – (Pull Out). Repetition of step No. 1 after the two previous steps. For each bracket, a new piece of the SS wire was used. In total, 120 measurements were performed. Forcevaluesthatcausedmaximumandminimum deflection of the clips of five brands of self-ligating brackets were collected. From these values (eight brackets per group), a mean score was calculated, representing the force Table 1_Brackets tested. Fig. 1_A custom cylinder designed for the experiment. Table 2_ The data allows the researcher to compare the mean scores between steps Nos. 1 and 3, after subjecting the clips to the force of 20 N for two hours in step No. 2. Table 3_Results of the experiment in all three steps. (Tables and photo/ Provided by Dr. Celestino Nobrega) Table 1 Table 2 Table 3 Fig. 1

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