Atefe Saffar Shahroudi
Abstract
Objectives: The aim of this study was to assess the effects of different orthodontic vertical loop height and design on its force characteristics at different amount of loop activation by means of finite element method (FEM) analysis. Materials and Methods: Four 3D FEM models were designed of double ...
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Objectives: The aim of this study was to assess the effects of different orthodontic vertical loop height and design on its force characteristics at different amount of loop activation by means of finite element method (FEM) analysis. Materials and Methods: Four 3D FEM models were designed of double vertical open loop (DVOL) and double vertical helical open loop (DVHOL) each of them in two heights of 6 mm and 7 mm. The loops were modeled in SolidWorks 2006 and then transferred to ANSYS Workbench. The loops were activated in buccolingual direction for 0.1, 0.3, 0.5, 0.7 and 1 mm simulating an activated multi-loop arch wire to align a posterior tooth which is erupted with buccal or lingual inclination. The force delivered at each amount of activation for the four loop designs were measured and compared. Results: The results of this study showed that the minimum amount of force was delivered by double vertical helical open loop with the height of 7 mm at the activation of 0.1 mm which was about 1.06E-01 N. The maximum amount of force was 2.2199 N which was delivered by double vertical open loop with height of 6mm at 1 mm activation. At each amount of activation the value of exerted force followed this order: DVOL 6 mm > DVOL 7 mm > DVHOL 6 mm > DVHOL 7 mm.
Conclusions: According to this FEM study, considering its limitations, adding a helix in a double vertical open loop as well as increasing the height of loop can reduce the value of delivered force.
Hasan Salehi; Sepide Arab
Abstract
Background: Alignment of the teeth as the first stage of comprehensive orthodontic treatment has widely been addressed. Several methods such as using super elastic arch wires, multi-strand wires and incorporation of various loops into the round stainless steel wires have been suggested in this stage.
Objectives: ...
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Background: Alignment of the teeth as the first stage of comprehensive orthodontic treatment has widely been addressed. Several methods such as using super elastic arch wires, multi-strand wires and incorporation of various loops into the round stainless steel wires have been suggested in this stage.
Objectives: The aim of this study was to investigate and compare the horizontal forces produced by six various loop designs in different amounts of activation using the finite element method. Materials and Methods: The Finite Element Model (FEM) was used to design and compare the horizontal forces of round 0.014 inches stainless steel vertical open loop, vertical closed loop, vertical helical open loop, vertical helical closed loop, plain vertical loop and the squash loop. The forces were measured at 0.1, 0.4, 0.8 and 1mm activations. Results: For all activations, vertical open loop had the highest horizontal force; while vertical helical closed loop showed the lowest force.
Conclusions: The design of vertical loops influences the horizontal force in all activations, immensely.
Allahyar Geramy; Reza Jelodar; Hasan Salehi
Abstract
Aim: The aim of this study was to assess the effects of different loop forms in continuous arch technique on its force characteristics in the anterior retraction arch wires.Material and Method: Six 3D finite element models were designed of an anterior retraction arch wire formed and included four average ...
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Aim: The aim of this study was to assess the effects of different loop forms in continuous arch technique on its force characteristics in the anterior retraction arch wires.Material and Method: Six 3D finite element models were designed of an anterior retraction arch wire formed and included four average sized anterior brackets and the palatal wall of the bracket slot of the canines. The models were similar except for the height and angle of the loop legs. The left side loop was kept constant in all stages of the study while modifying the right side loop height or vertical leg's angulations. SolidWorks 2006 was selected for the modeling phase and ANSYS Workbench Ver. 11.0 for the calculations. Mesializing force on molar, medially directed force on canine, and anterior retraction forces were evaluated.Results: According to the results, loop height in one side cannot affect the other side loop force characteristic directly; A gradual increase of the force difference between two side of the anterior retraction arch wire is shown. The mesializing force on molar is also increased with almost the same manner. The other findings related to loop leg divergence shows a difference between two sides but the differences are almost the same with varying degrees of divergence. Although the forces are not the same in both sides but the difference remained almost constant.
Conclusion: Arch wires may seem to be symmetric but may act asymmetric. Difference in anterior teeth retraction may be due to some asymmetries in arch wire fabrication which needs further considerations.
