INTRODUCTION: Arch wires are the primary means of generating forces for orthodontic treatment.They are one of the active components of fixed appliances. They bring about various tooth movements through the medium of brackets and buccal tubes.Arch wires are fabricated from a myriad of alloys. Understanding the basic material characteristics is essential in selecting wires for use in treatment. The bottom line is that the wire act as springs in clinical orthodontics.Mechanical properties of a material are determined by several factorssuch as variation of intrinsic properties alters the nature of the alloy itself,extrinsic properties are macroscopic features (diameter, length) and can be determined by the clinician.Three major properties of archwires are critical in defining their clinical usefulness:strength,stiffness and range.1