A comparison of different ligation methods on friction

Introduction: An elastomeric module with a polymeric coating has been developed to reduce the friction of sliding mechanics. This in-vitro study examined the stability of the coating and compared the frictional properties of coated modules with those of other common ligation methods. Methods: Six ligation methods (regular uncoated, slick [coated], conventional silver, easy-to-tie, silicone-impregnated, and standard silver modules) were used with standard stainless steel brackets and 0.019 x 0.025-in archwires, and resistance to movement was measured. Two self-ligating (Speed [Strite Industries, Cambridge, Ontario, Canada] and Damon 2 [Sybron Dental Specialities Ormco, Orange, Calif ]) brackets were also tested. Results: The Damon 2 self-ligating brackets produced less friction than the other ligation methods, followed by the coated modules. There was no significant difference between the frictional resistance of brackets ligated with regular uncoated, silicone-impregnated, and easy-to-tie modules. Speed self-ligating brackets produced less friction than regular uncoated, conventional silver, and standard silver modules. The frictional properties of coated modules were not significantly affected by repeating the test 5 times or by storage in saliva for a week. Conclusions: Damon 2 brackets produced no recordable friction of ligation. Coated modules produced 50% less friction than all other ligation methods except Damon 2. The coating was resistant to the simulated effects of the oral environment. Different methods of human saliva application were found to affect the frictional properties of the coating.