| This study evaluated bracket-archwire frictional resistance as a function of ligation method and archwire vibration. In vivo archwire vibrations were measured to obtain frequencies and amplitudes for ex vivo testing. Active and passive ligation methods were compared for 9 vibration scenarios utilizing a friction testing apparatus, where a nickel titanium spring was attached to a wire bonded to an upper right canine bracket to create a 1500 cN-mm moment. As retraction forces were applied, the amount of time (ln, s) for each bracket configuration to move along a stainless steel wire was recorded in 90 trials. Results indicated that trials containing medium (150mV) and high (190mV) amplitude vibrations had significantly less friction, 4.81+/-2.08 and 4.67+/-2.00, respectively, than those subjected to low (110mV) amplitudes, 5.80+/-1.39 (p=0.04). There were no significant differences between passive and active ligation methods (p=0.100) and frequency of vibrations (p=0.317) on bracket-archwire frictional resistance. |
