To establish a simplified method for measuring the edge bevel radius of 0.019 × 0.025-in steel rectangular orthodontic wires, achievable in the clinical environment, and to compare it with the photographic method. Aided by the AutoCAD™ 2016 software, the theoretical mathematical relationship was...

To establish a simplified method for measuring the edge bevel radius of 0.019 × 0.025-in steel rectangular orthodontic wires, achievable in the clinical environment, and to compare it with the photographic method. Aided by the AutoCAD™ 2016 software, the theoretical mathematical relationship was determined between the edge rounding radius and cross-sectional dimensions (height, width, diagonals), through rectangle drawings that represent cross-sections. Two hundred segments (n = 20) were obtained from the posterior portions of 100 archwires from 10 brands (Dentaurum™; American-Orthodontics™; GAC™; 3M-Unitek™; Abzil™; Morelli™; Orthometric™; Aditek™; A-Company™; Orthomundi™). The cross-sectional measures of each segment were obtained with a micrometer and a caliper, and the edge bevel radii of these segments were calculated with the use of a mathematical formula. For the “gold standard”, the segments were included longitudinally in a phenolic resin cylinder, cross-sectioned, polished, and photographed in scanning electron microscope (SEM). The images were amplified 770× and the radii were measured with an acetate template. The micrometer and caliper measuring methods were subjected to Bland-Altman analysis and compared with the gold standard (SEM), considering ±10 μm as the maximum acceptable difference between methods. In the micrometre measurement, 95% of the differences from the standard were within the limits of agreement (−7.21 and 5.56 μm). For the caliper method, 95% of the differences were between −5.46 and 19.83 μm, which exceeded the fixed limit ±10 μm. The calculation method with micrometre measurements is equivalent to the photographic method, but there is no such equivalence for the caliper measurements

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