The effects of third-order torque and self - Saint Louis University

0.025-inch NuBryte Standard Arch stainless steel wires
(Part Number 03-925-51; GAC International, Bohemia, NY).
Because transmission of third-order torque-forces is
directly influenced by wire size, ten percent of the test-
wires (21 wires) were arbitrarily chosen and measured with
a digital micrometer (Model APB-2D, Mitutoyo Corporation,
Kanagawa, Japan). Their average cross-sectional dimensions
were calculated toward third-order clearance estimates.
Five different pairs of canine and second-premolar
brackets, all with 0.022-inch slots, were selected for this
study. The “passive” self-ligating attachments were Damon
3MX brackets (Ormco Corporation, Glendora, CA) with passive
facial slides (Figure 3-5) and SmartClip brackets
(3M/Unitek Corporation, Monrovia, CA) with passive C-clips
(Figure 3-6). The “active” self-ligating attachments were
In-Ovation R brackets (GAC International, Bohemia, NY;
Figure 3-7) with sliding spring-clips and Time2 brackets
(American Orthodontics, Sheboygan, WI; Figure 3-8) with
rotating spring-clips. The traditional crown-attachments
were the Victory-series MBT brackets (3M/Unitek
Corporation, Monrovia, CA; Figure 3-9); wires were tied in
the slots with silver Unistick elastomeric ligatures (Part
Number 854-262; American Orthodontics, Sheboygan, WI).
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