nie objectives of this study were to evaluate physical properties of the laser welded orthodontic wires. The tensile fracture 1(kId, micro Vikers hardness and microstructures on the welded area of four different orthodontic wires, Cr-Co, Stainless ,ted, `I NIA, Ni-Ti, were tested
´I´he results were obtained as follows;
1. All 4 materials used in this study were able to be welded by laser. Cr-Co and S-S wires could be"welded ´ on both lap
and butt joints, TNIA wires were a part of lap and all butt joints, and Ni-Ti wires were for lap joints only.
The tensile-fracture loads of Cr-Co and S-S wires were higher on lap joint than butt joint welding and it shoved higher
Viiiue at 7-12J lap welding of Cr-Co wires and at more than 6J lap welding of S-S wires than control(p<0.05).
3, The tensile-fracture loads of TMA wires were higher on butt joint than lap joint welding and it decreased as the energy
l level increased, and every experin´}ental group showed lower value than control(p<0.05),
4. Ni-Ti wires were higher tensile-fracture load than control at 8-IIJ(p<0.05):
7. "Fhu hardness of Cr-Co and S-S wires were higher than TNIA and Ni-Ti wires. The hardness of laser exposed area of "Cr-Co nd S-S-wires decreased-, whilethat of TMA and Ni-Ti-wires tended to increase.
x ,.
1 i ermal effect limits of laser welded areas were 0.5mm for Cr-Co and´S-S wires, 0.6mm for TMA wires and O.Vmm for Ni Ti
. i mi(´rc stricture views all the experimental groups showed clear boundary of thermal effect limits and microstructe a1)1)eared at Cr-Co, S-S and TMA wires.
In Cr-Co, S-S and Ni-Ti wires, laser welding showed the higher bonding strength than electrical resistance spot welding. 1´he laser welding could be the good alternative way to use in, the routine orthodontic wire.
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