Friction produced by a new passive ligature in sliding mechanics

Objective: This in vitro study investigated the effect of ligation method on friction and evaluated the efficacy of a new low-friction ligation——Leone SlideTM from Italy Leone Orthodontic Products. Methods: A friction testing apparatus was designed and used to assess the resistance of an 0.018X0.025-inch stainless steel rectangular wire that was ligated to an upper second premolar bracket (3M Unitek MBT mini).Four ligation methods (Leone SlideTM ligature, conventional elastomeric ligature, loose SS ligature, tight SS ligature) were used. For each ligation, the archwire was drawn through the bracket at a rate of 5mm/min over a distance of 2mm.The resistance to sliding were measured at 13 second-order angulations, which ranged from 0 to 9°.Linear regression analysis of RS against è was used. Results: Different ligation methods can produce different ligation forces or normal loads on archwires, therefore exhibited different friction. In the passive configuration, or the region in which second-order angulation(è) was less than critical contact angle for binding(èc), resistance to sliding was a relatively constant value, Leone SlideTM ligature produced the lowest friction that even can be ignored. In the active configuration, or the region in whichèwas greater than èc, resistance to sliding increased linearly as the angulation increased. At all angles, Leone SlideTM ligature presented the lowest friction, followed by loose SS ligature and conventional elastomeric ligature, while, tight SS ligature produced the highest friction due to its highest ligation force. Conclusions: As a new passive ligature system, Leone SlideTM is able to produce significantly lower levels of frictional forces in vitro when compared with conventional ligatures.