In vitro study of frictional forces during sliding mechanics of "reduced-friction" brackets.

This study evaluated the static friction force created between archwires and "reduced-friction" brackets during sliding mechanics. Five different brands of "reduced-friction" brackets were used: group A: NuEdge (TP Orthodontics, LaPorte, Ind); group B: Discovery (Dentaurum, Ispringen, Germany); group C: Synergy (Rocky Mountain Orthodontics, Denver, Colo); group D: Friction Free (American Orthodontics, Sheboygan, Wis); and group E: TIME, a self-ligating bracket (American Orthodontics). Group F (Omni Arch, GAC International, Bohemia, NY) served as a control group. Each group contained 75 stainless steel brackets with.022 x.028-in slots. Three stainless steel wires were tested:.018,.018 x.025, and.019 x.025 in. To take second-order bends into account, the brackets were set at either 5 degrees or 10 degrees to the wires. Each bracket was set in a special device, which was placed on the base of the testing machine. A wire ligated to the bracket was attached to the crosshead of the machine and pulled at a speed of 10 mm/min for a distance of 5 mm. Significant differences were found in the static friction forces among the different groups. Group D (Friction Free) showed the lowest and group E (TIME) showed the highest friction forces (higher than the normal friction brackets [Omni Arch]). This study demonstrates that not all brackets provide "reduced friction," even though the manufacturers describe them as doing so.