Alignment Efficiency of Superelastic Coaxial Nickel-Titanium

The preliminary phase of any orthodontic treatment with fixed appliances is the alignment and leveling of teeth. Leveling is the process in which the incisal edges of the anterior teeth and the buccal cusps of the posterior teeth are placed on an ideal horizontal level; and alignment is the lining up of teeth of an arch in order to achieve normal contact point relationship. In the alignment phase, the arch wire used should have the property of delivering light continuous forces for a long period of time [1]. This can be achieved by either varying the cross-section of the arch wire or by varying the elastic modulus of the wire. The shape of the initial arch wire-whether solid, multi-stranded, looped or tubular-imparts a unique force level, strictly because of its physical characteristics by varying elastic modulus. The material composition of the wire also affects its force characteristics. Metallurgical advances have produced initial arch wires that can deliver light forces even under extreme physical deformation [2].