Determination of the force systems produced by different configurations of tear drop orthodontic loops

Admin Dental Press

Edition V18N02 | Year 2013 | Editorial Online Article | Pages 19 to 19

Guilherme Thiesen , Roberto Hideo Shimizu , Caio Vinicius Martins Do Valle , Karyna Martins Do Valle-corotti , Jefferson Ricardo Pereira , Paulo Cesar Rodrigues Conti

Objective: To determine the mechanical characteristics of teardrop loop with and without helix fabricated using different metal alloy compositions (stainless steel and beta-titanium), submitted to different intensities of mbends preactivation (0° and 40°), and with different cross-sectional dimension of the wire used to build these loops (0.017 x 0.025-in and 0.019 x 0.025-in). Methods: Eighty loops used to close spaces were submitted to mechanical tests. The magnitudes of horizontal force, the moment/force ratio, and the load/deflection ratio produced by the specimens were quantified. Loops were submitted to a total activation of 5.0 mm and the values were registered for each 1.0 mm of activation. For statistic data analysis, a analysis of variance was performed and a Tukey’s Multiple Comparison test was used as supplement, considering a 5% level of significance. Results: In general, teardrop loops with helix produced lower magnitudes of horizontal force and load/deflection ratio, and higher moment/force ratio than teardrop loops without helix. Among all analyzed variables, metal alloy composition presented greater influence in the horizontal force and in the load/deflection ratio. The moment/force ratio showed to be more influenced by the preactivation of loops for space closure.

Biomechanics, Orthodontic space closure, Tooth extraction, Orthodontics,

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