Frictional resistance of different types of self-ligating brackets with different wire combinations

The purpose of this study was to compare the effect of the mode of ligation on the frictional resistance of ceramic brackets and the effect of the bracket material on the frictional resistance whether it is static or kinetic. To achieve this one passive self-ligating ceramic bracket (Damon Clear 2), one active self-ligating ceramic bracket (Empower Clear) in addition to one passive self-ligating metal bracket (Damon Q) were used. These brackets were coupled with two sizes of stainless steel (SS) archwires (0.017 x 0.025-in and 0.019 x 0.025-in). A universal testing machine was used to pull the brackets along the straight distal end of the wire segments at a crosshead speed of 5 mm/min over a distance of 8 mm/min. The test was undergone under dry conditions. The results showed that the passive self-ligating brackets (PSLB) had significantly lower static friction (SF) and kinetic friction (KF) than the active self-ligating bracket (ASLB) with no significant differences between the ceramic and metal PSLB’s. Also inceasing wire size increased the SF and KF for the PSLB’s but did not affect the ASLB significantly.