Dental Arch Form; Arch Size

Statement of the Problem: The stability of orthodontic treatment depends on pre-serving the patient’s pretreatment arch form and arch size during and after treatment. Purpose: This investigation was aimed to study the size and shape of Iranian man-dibular dental arch and evaluate the correlation of their average dental arch with commercially available preformed rectangular nickel-titanium arch wires. Materials and Method: In this study, 148 subjects were selected among students of Shiraz University of Medical Sciences. The inclusion criteria were having Angle class I in molar and canine relationships, and normal growth pattern. Intercanine and intermolar widths were measured after scanning their mandibular dental casts. Three main arch form templates; square, ovoid and tapered (Orthoform TM; 3M, Unitek, CA, USA) and 12 commercially available preformed mandibular nickel-titanium arch wires were scanned. Intercanine and intermolar widths of arch wires were com-pared with dental arch widths of the study samples. Arch width, arch form and the most appropriate arch wire were determined for each cast. Student’s t-test was use