<abstract xmlns="http://www.w3.org/1999/xhtml">

<sec>
<h3>Background</h3>
<p>It has been claimed that the opus loop is capable of delivering a constant and optimum M/F ratio without the need for gable bends.</p>
</sec>
<sec>
<h3>Objective</h3>
<p>To compare the forces, moments and moment/force (M/F) ratios of the opus loop, L–loop, T–loop and vertical helical closing loop (VHC loop) in a segmented arch with the finite element method (FEM).</p>
</sec>
<sec>
<h3>Methods</h3>
<p>The FEM was used to compare 3D models of closing loops in rectangular (0.016 x 0.022 inch) stainless steel wire. The L–, T– and VHC loops were designed with and without preactivation bends. The opus loop had no preactivation bends.</p>
<p>The T–Loops were 10 mm in height and 10 mm in length. The horizontal and vertical forces, the moments and the M/F ratios at the alpha and beta ends were recorded at 0, 0.1, 0.4, 0.7 and 1 mm intervals.</p>
</sec>
<sec>
<h3>Results</h3>
<p>The highest horizontal and vertical forces were produced by the L–loop (with and without preactivation bends) and in most cases the lowest forces were produced by the VHC loop. Loops with preactivation bends produced marked changes in the M/F ratio and loops without preactivation bends low, but relatively constant, M/F ratios over the full range of activation. Of the loops modelled without preactivation bends the opus and T-loop had the highest M/F ratios (7.20 – 7.67 mm at the anterior ends).</p>
</sec>
<sec>
<h3>Conclusion</h3>
<p>Stainless steel opus and T–loops without preactivation bends had constant M/F ratios, but both loops failed to deliver the optimum M/F ratio of 10:1.</p>
</sec>
</abstract>

Background
It has been claimed that the opus loop is capable of delivering a constant and optimum M/F ratio without the need for gable bends.


Objective
To compare the forces, moments and moment/force (M/F) ratios of the opus loop, L–loop, T–loop and vertical helical closing loop (VHC loop) in a segmented arch with the finite element method (FEM).


Methods
The FEM was used to compare 3D models of closing loops in rectangular (0.016 x 0.022 inch) stainless steel wire. The L–, T– and VHC loops were designed with and without preactivation bends. The opus loop had no preactivation bends.
The T–Loops were 10 mm in height and 10 mm in length. The horizontal and vertical forces, the moments and the M/F ratios at the alpha and beta ends were recorded at 0, 0.1, 0.4, 0.7 and 1 mm intervals.


Results
The highest horizontal and vertical forces were produced by the L–loop (with and without preactivation bends) and in most cases the lowest forces were produced by the VHC loop. Loops with preactivation bends produced marked changes in the M/F ratio and loops without preactivation bends low, but relatively constant, M/F ratios over the full range of activation. Of the loops modelled without preactivation bends the opus and T-loop had the highest M/F ratios (7.20 – 7.67 mm at the anterior ends).


Conclusion
Stainless steel opus and T–loops without preactivation bends had constant M/F ratios, but both loops failed to deliver the optimum M/F ratio of 10:1.

M/F ratios of four different closing loops: 3D analysis using the finite element method (FEM)

Australasian Orthodontic Journal

This work is licensed under the Creative Commons Attribution 4.0 International License.

Background
It has been claimed that the opus loop is capable of delivering a constant and optimum M/F ratio without the need for gable bends.


Objective
To...

M/F ratios of four different closing loops: 3D analysis using the finite element method (FEM)

Published Online: Dec 13, 2023

Page range: 121 - 126

Received: Aug 01, 2005

Accepted: Aug 01, 2006

DOI: https://doi.org/10.2478/aoj-2006-0012

© 2006 Mohammad Reza Safavi et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.