Frictional tests were performed on three ceramic brackets: monocrystalline (Inspire ICE), polycrystalline (InVu), polycrystalline with metal slot (Clarity), and one stainless steel bracket (Dyna-Lock).

Thirty brackets of each were tested, all with .022" slots, in combination with stainless steel and nickel-titanium wires .019" × .025", at 0° and 10° angulation, in artificial saliva.

Arch wires were pulled through the slots at a crosshead speed of 10 mm/min.

There were statistically significant differences between the groups of brackets and wires studied (p < .05).

The polycrystalline brackets with metal slots had values similar to those of conventional polycrystalline brackets, and the monocrystalline brackets had the highest frictional forces.

The nickel-titanium wires produced the lowest friction.

The addition of metal slots in the polycrystalline brackets did not significantly decrease frictional values.

Nickel-titanium wires produced lower friction than those of stainless steel.