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

Conventional Ligation
Orthodontic ligatures existed prior to the use of the
modern fixed appliance. In 1728, Fauchard published a book
called “Le Chirurgien Dentiste” in which he described his
“Bandeau” device. Ligatures were extended from this
horseshoe-shaped device to facilitate simple tooth
movement. Angle’s edgewise appliance was introduced in
1925, and the original design has evolved to the most
commonly used orthodontic appliance today. It was the
first fixed appliance to feature ligatures as an essential
part of the appliance. Early ligatures were materially
precious metals. 49,50
In modern clinical orthodontics, the conventional
methods of tying archwires into bracket-slots are with
either small stainless steel wires or elastomeric ties.
These ligatures, although relatively inexpensive and easy
to place, have been criticized with the recent interest in
orthodontic friction. Studies have shown a relationship
between normal forces of ligation and resistance to
sliding. Using a pneumatically controlled surface to
simulate the force of ligation on a sliding wire, Stannard
et al. 17 discovered a proportional increase in friction with
increasing ligating force. Keith, Jones and Davies, 51 with
three magnitudes of ligating force, found a similar
20