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

<italic>Objectives</italic>: This in vitro study investigated the loads (“forces”), moments and moment:force ratios (M:F) generated during activation and deactivation of three closing loop designs constructed from two different orthodontic wire alloys.
<italic>Method</italic>: The forces and moments of non-preactivated vertical U-Loops, symmetrical T-Loops, and asymmetrical T-Loops (X-Loops) made from titanium molybdenum alloy (TMA) and Japanese nickel titanium alloy (NiTi) were measured at 35.6°C ± 0.5°C. The M:F ratios generated during activation and deactivation were calculated for each loop. Analysis of covariance was used to identify statistical differences between loop material and design.
<italic>Results</italic>: The forces, moments and M:F ratios produced by the NiTi closing loops were significantly less than those from the TMA loops. NiTi T-Loops produced a relatively constant force during activation compared to the same design in TMA. The TMA X-loop produced a maximum M:F ratio of 9.4:1. No closing loop produced the optimum M:F ratio required for translational en masse tooth movement.
<italic>Conclusions</italic>: Optimum M:F ratios for translation are not possible with non-preactivated vertical U-Loops, symmetrical T-Loops, and asymmetrical T-Loops (X-Loops) made of NiTi and TMA alloys.
</abstract>

Objectives: This in vitro study investigated the loads (“forces”), moments and moment:force ratios (M:F) generated during activation and deactivation of three closing loop designs constructed from two different orthodontic wire alloys.
Method: The forces and moments of non-preactivated vertical U-Loops, symmetrical T-Loops, and asymmetrical T-Loops (X-Loops) made from titanium molybdenum alloy (TMA) and Japanese nickel titanium alloy (NiTi) were measured at 35.6°C ± 0.5°C. The M:F ratios generated during activation and deactivation were calculated for each loop. Analysis of covariance was used to identify statistical differences between loop material and design.
Results: The forces, moments and M:F ratios produced by the NiTi closing loops were significantly less than those from the TMA loops. NiTi T-Loops produced a relatively constant force during activation compared to the same design in TMA. The TMA X-loop produced a maximum M:F ratio of 9.4:1. No closing loop produced the optimum M:F ratio required for translational en masse tooth movement.
Conclusions: Optimum M:F ratios for translation are not possible with non-preactivated vertical U-Loops, symmetrical T-Loops, and asymmetrical T-Loops (X-Loops) made of NiTi and TMA alloys.

Moment to force ratio characteristics of three Japanese NiTi and TMA closing loops

Australasian Orthodontic Journal

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

Objectives: This in vitro study investigated the loads (“forces”), moments and moment:force ratios (M:F) generated during activation and deactivation of three...

Moment to force ratio characteristics of three Japanese NiTi and TMA closing loops

Published Online: Dec 13, 2023

Page range: 107 - 114

Received: Jun 01, 2004

Accepted: Aug 01, 2004

DOI: https://doi.org/10.2478/aoj-2004-0014

© 2004 Mark Kum et al., published by Sciendo

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