Effects of third-order torque on frictional force of self-ligating brackets

Abstract

Objective: To investigate the effects of third-order torque on frictional properties of self-ligating brackets (SLBs). Materials and Methods: Three SLBs (two passive and one active) and three archwires (0.016 3 0.022-inch nickel-titanium, and 0.017 3 0.025-inch and 0.019 3 0.025-inch stainless steel) were used. Static friction was measured by drawing archwires though bracket slots with four torque levels (06, 106, 206, 306), using a mechanical testing machine (n 5 10). A conventional stainlesssteel bracket was used for comparison. Results were subjected to Kruskal-Wallis and MannWhitney U-tests. Contact between the bracket and wire was studied using a scanning electron microscope. Results: In most bracket-wire combinations, increasing the torque produced a significant increase in static friction. Most SLB-wire combinations at all torques produced less friction than that from the conventional bracket. Active-type SLB-wire combinations showed higher friction than that from passive-type SLB-wire combinations in most conditions. When increasing the torque, more contact between the wall of a bracket slot and the edge of a wire was observed for all bracket types. Conclusions: Increasing torque when using SLBs causes an increase in friction, since contact between the bracket slot wall and the wire edge becomes greater; the design of brackets influences static friction.

Frictional resistance of active and passive aesthetic self-ligating brackets with different orthodontic wire sizes

“…In like manner, the results of Muguruma et al 13 were in accordance with those of the present study except in one situation in which the brackets were combined with the 0.019 x 0.025-in SS wire with the application of a 30 o torque. This can be attributed to the high degree of the applied torque and the high stiffness of the wire.…”

Characterization of the coatings covering esthetic orthodontic archwires and their influence on the bending and frictional properties

“…During tooth movement, the friction between the bracket and the archwire is a primary concern. 19,20 Characteristics such as surface roughness, hardness, and elastic modulus depend on the wire's composition, thermal history, and cross-sectional dimensions. These characteristics also influence bending and frictional properties.…”

“…The static frictional force generated with each wire/ bracket combination was tested (n ¼ 10) under dry conditions at 258C using a custom-fabricated frictiontesting device attached to the universal testing machine (EZ Test, Shimadzu). 20 Each bracket was bonded to a stainless-steel plate using a bracketmounting device with a nonfilled adhesive resin (Superbond, Sun Medical, Shiga, Japan), and the bracket was positioned at 108. A 5-cm segment of wire was then ligated to the bracket using an elastomeric ligature (Alastik Easy-To-Tie Ligatures, 3M Unitek, Monrovia, Calif).…”

Mechanical properties of orthodontic wires covered with a polyether ether ketone tube

“…23, 24 The main factors that affect frictional resistance include the type of bracket; the physical properties, size, and alloy of the archwires; and the method of ligation. [25][26][27][28][29][30][31] Several methods have been proposed for reducing the friction between the brackets and wire, including the use of surface treatments such as ion implantation, poly(tetrafluoroethylene) coating, and diamond-like carbon coatings of the wires and/or brackets.…”