root parallelism of canine and second premolar in preadjusted and standard edgewise systems: a comparative study

background and aims: one of the main goals of standard orthodontic treatment is having the roots of teeth adjacent to extraction sites parallel to each other. the purpose of this study was to compare standard edgewise and preadjusted straight wire (mbt) methods in achieving this goal. materials and methods: for comparing root parallelism, 228 maxillary quadrants and 225 mandibular quadrants of 127 patients in whom 1 st premolar had been extracted during orthodontic treatment plan were evaluated. on pre and post-treatment panoramic views long axis of canines and 2 nd premolars of each quadrant were traced and the angulations between them were measured to assess root parallelism. for comparing mean value of angulations measured in post-treatmentviews between mbt and sew method, independent t-test and for comparing root parallelism of canines and 2 nd premolars chi-square test was used. results: evaluating root movement and root parallelism of maxillary and mandibular canines and 2 nd premolars did not show any statistically significant difference between treatment groups. (p> 0.05) conclusion: there is no difference between 2 methods of mbt and standard edgewise in achieving favorable root parallelism of teeth adjacent to extraction site. if each of these methods is used properly good root parallelism can be achieved in most of the cases.