Effect of applied moment on resistance to sliding among esthetic self-ligating brackets

Abstract

Objective: To determine the effect of mode of ligation and bracket material on resistance to sliding (RS) by comparing various esthetic brackets of conventionally ligated and self-ligating (SL) designs under an increasing applied moment in the second-order dimension. Materials and Methods: Eight different commercially available esthetic brackets of SL and conventional elastomeric-ligated (CL) designs were mounted on a testing apparatus to simulate canine retraction using sliding mechanics and the application of a moment on 0. . The RS at calculated moments of 2000 g-mm and 4000 g-mm was determined and compared between the various brackets. Descriptive measures and one-way analysis of variance were used to calculate means and statistical differences among the bracket types. Results: The CL monocrystalline bracket displayed significantly greater (P , .05) RS than all other brackets tested. Among the other brackets, the range of RS values was 145.8-191.7 g and 291.9-389.2 g at moments of 2000 g-mm and 4000 g-mm, respectfully, though these differences were not significant (P , .05). All brackets tested displayed greater levels of RS (P , .05) at 4000 g-mm than at 2000 g-mm.Conclusion: With the exception of the CL monocrystalline bracket, all brackets displayed comparable amounts of RS regardless of mode of ligation or bracket slot material. (Angle Orthod. 2014;84:134-139.)

Frictional resistance of self-ligating versus conventional brackets in different bracket-archwire-angle combinations

“…These results allow us to conclude that the same outcome occurs even in rectangular wires, which is in accordance with some previous studies 5,6,9 but in discordance with other authors, who found no significant difference 12,13,22,23,28 or observed greater friction in the self-ligating brackets 25 . These discrepancies can be attributed to differences between experimental models, including shapes, sizes and prescriptions of self-ligating brackets, as well as clips or caps made of different materials.…”

“…Studies comparing self-ligating brackets with different ligating systems for conventional brackets have reported and showed that the former has a significantly lower level of frictional resistance 1,4,6-9,17,18,20,27 . However, some studies that evaluated rectangular wires 12,13,23,28 and applied moments 22,23 showed no differences between self-ligating and conventional brackets 12,13,22,28 . Some authors still found a greater friction in the self-ligating brackets 25 .…”

Resistance to sliding of orthodontic archwires under increasing applied moments

“…Conventional brackets are suggested to have increased frictional resistance to sliding caused by the ligatures used to hold the archwire in place, resulting in reduced treatment efficacy. [1][2][3] Conversely, self-ligating brackets are suggested to have reduced frictional resistance to sliding as they do not require additional ligatures. 4 Fixed orthodontic appliances have traditionally used stainless steel brackets together with a variety of archwire materials.…”

Are self-ligating brackets an advantageous alternative for non-extraction treatments?

“…With the exception of single crystalline ceramic brackets, all the tested brackets (conventional brackets from Clarity TM , Inspire Ice TM , Spirit MB TM , and Mystique TM , and self-ligating brackets from Clarity SL TM , In-Ovation C TM , In-Ovation R TM , and Smart Clip TM ) offer a comparable rate of resistance to sliding based on the bracket (self-ligating or not) and on the material of the slot of the bracket 35 .…”