Friction between Archwires of Different Sizes, Cross-Section and Alloy and Brackets Ligated with Low-Friction or Conventional Ligatures

Abstract

Objective: To test the null hypothesis that no statistically significant difference in frictional resistance is noted when round or rectangular archwires are used in conjunction with low-friction ligatures (small, medium, or large) or conventional ligatures. Materials and Methods: A total of 10 stainless steel brackets, a 0.022-in slot, and various orthodontic archwires, ligated with low-friction ligatures or conventional ligatures, were tested to compare frictional resistance. The archwires employed were 0.014-in and 0.016-in nickel titanium (NiTi), 0.018-in stainless steel (SS), 0.016 ϫ 0.022-in NiTi, 0.016 ϫ 0.022-in SS, 0.017 ϫ 0.025-in titanium molybdenum alloy (TMA), 0.017 ϫ 0.025-in NiTi, 0.017 ϫ 0.025-in SS, 0.019 ϫ 0.025-in SS, and 0.019 ϫ 0.025-in NiTi. Each bracket/archwire combination was tested 10 times in the dry state at an ambient temperature of 34ЊC. Results: Low-friction ligatures with round archwires showed statistically significantly lower frictional resistance than did conventional ligatures. When coupled with 0.016 ϫ 0.022-in NiTi and SS, no statistically significant difference was observed among the four groups. When coupled with 0.017 ϫ 0.025-in archwires, low-friction ligatures showed statistically significantly greater frictional resistance than was seen with conventional ligatures. When coupled with 0.019 ϫ 0.025-in NiTi, low-friction ligatures showed statistically significantly greater frictional resistance than did conventional ligatures, but no difference among the four groups was observed with the 0.019 ϫ 0.025-in SS. No significant difference was assessed among low-friction ligatures of different sizes. Conclusion: Low-friction ligatures show lower friction when compared with conventional ligatures when coupled with round archwires, but not when coupled with rectangular ones. (Angle Orthod. 2009;79:111-116.)

Frictional Characteristics of the Newer Low-friction Elastomeric Ligatures

“…This was in agreement with the findings of Baccetti and Franchi, 16 Tecco et al, 17 and Sivaraj. 18 One of the most favorable features of the Slide™ ligatures is the possibility of turning any type of existing conventional bracket system into a ''low-friction'' bracket system.…”

Active and passive self-ligation—a myth?

“…RS measured under these circumstances was due to experimental flaws due to incorrect alignment of the archwire within the bracket slot. [5][6][7][8] With the use of a stainless-steel chain almost all unwanted effects of malalignment, angulation, or torque between the bracket slot and the archwire were eliminated in the present study. The chain allowed the archwire to align itself perfectly within the bracket slot.…”

“…[1][2][3][5][6][7][8][9][10] Many of the discrepancies in the results can be attributed to the different testing designs. Some authors used an experimental setup in which the archwire was pulled straight through the bracket slot without any angulation, torque, or force-moment applied.…”

Frictional resistance of orthodontic wires tied with 3 types of elastomeric ligatures

“…These wires do not undergo as much deflection as lighter wires, however, they show a lower friction coefficient when compared with the thicker ones, 1,17,20,21 since the larger the wire size, the higher the friction coefficient. 1,6,20,22 The method of wire ligation to the bracket also influences frictional resistance 23 and it is proportional to the ligation force and friction coefficient of the surfaces that are in contact. 24 Therefore, this study was developed with the purpose of comparing the frictional resistance produced by different elastomeric ligatures, one low-friction ligature and two conventional ligatures, since they are the first choice of several orthodontists.…”