Allahyar Geramy; Tahura Etezadi; Ahmad Reza Shamshiri; Mohammad Javad Kharazifard
Abstract
Introduction: An appropriate force system is a perquisite of desirable and predictable tooth movements during orthodontic treatment. Complete knowledge about the generated forces and moments by loops is essential to choose the best one for every situation.The aim of this study was to establish a mathematical ...
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Introduction: An appropriate force system is a perquisite of desirable and predictable tooth movements during orthodontic treatment. Complete knowledge about the generated forces and moments by loops is essential to choose the best one for every situation.The aim of this study was to establish a mathematical equation to bring about a relationship between the L-loop height, width, activation and the produced force.Materials and methods: Six 3D finite element models were designed for L-loop without preactivation bends. Loops were designed with different widths (w) and heights (h). The cross section of wire was 0.016”× 0.022”. The distal end of each model was activated 1 mm in 0.1 mm intervals. The force produced by activation in a 0.1 millimeter increment was recorded. Results: Force findings were different according to the loop parameters defined. The produced force varies from 0.106 to 0.228 N for a 0.1 millimeter of activation and increased from 1.07 to 2.27 N in 1.0 mm of activation.Conclusion: The magnitude of force by L-loop can be estimated through adjustment of vertical part and activation as Increments of activation increased the delivered force while Increasing L-loop height decreased the generated force.
Allahyar Geramy; Tahoora Etezadi
Abstract
Desirable tooth movements need optimal force systems. Loops are employed to move teeth properly. L-loop is used frequently due to its ease of fabrication. The aim of this study is to assess the expected forces and moments when a definite length of wire is bent to form L-loop. In other words, the effect ...
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Desirable tooth movements need optimal force systems. Loops are employed to move teeth properly. L-loop is used frequently due to its ease of fabrication. The aim of this study is to assess the expected forces and moments when a definite length of wire is bent to form L-loop. In other words, the effect of loop height and width on the produced force and moment is evaluated by the finite element method (FEM). Materials and methods: Six 3D finite element models were designed of an L-loop without pre-activation bends keeping the total lengths of wire equal to 24.34+/- 0.5 mm. The cross section of wire was 0.016”× 0.022”. The force produced by activation in a 0.1 millimeter increment was recorded. Results: In model L1, the findings start with 0.086 N in 0.1 mm of activation and increased to 0.88 N in 1mm of loop opening. The pattern of findings was almost the same for other loop designs (L2 through L6) with an increase in findings. M/F ratios were almost constant in a loop design along its activation starting with 3 in L1 and reaching about 1.9-2 in L6. Conclusions: Moment to force ratios were almost constant in a loop design along its activation. increasing width and decreasing height with almost the same length of loop wire can increase force and therefor reduce M/F ratio.
