PROPERTIES OF Ni-Ti ARCH WIRES ON DIFFERENT INTER- BRACKET SPAN

The aim of all clinicians is to use low, continuous force in fixed appliance treatment. The “objective:”, was to determine the loading and unloading properties of 0.016” , 0.016” x 0.022” and 0.017” x 0.025”dimensions of conventional Ni - Ti and Super elastic Ni- Ti wires for inter bracket widths ( 5 mm and 6.5 mm). “Method:”, used was modified three point bending test, carried out on wires with Instron 4500 testing machine fitted with a 100N load cell calibrated on 2 kg range. The testing machine was operated at a crosshead speed of 2 mm/min and the analogue output was passed through computer.Brackets were embedded on two acrylic blocks .A cut was made in the 1st block to a depth of 10x10 mm and 13x10 mm in the centre of the 2nd block to allow deflection.”Results:”, showed that the force value was comparatively higher in 5 mm inter bracket width than the 6.5 mm inter bracket width for all dimension of wires. The conventional Nickel Titanium had force values compared to super elastic Nickel Titanium and linearly progressing. On unloading the super elastic Nickel Titanium had constant forces on higher deflection. On unloading the force values of 0.016”x0.022” and 0.016” super elastic Nickel Titanium wires were similar. The force values were lower on unloading compared to the loading for all the wires tested. “Conclusion:”,. On unloading the force values of higher dimension super elastic Nickel Titanium were similar to smaller dimension arch wires.