Aim: To quantitatively assess the extent of morphologic changes of the apical root area and root length of maxillary central incisors after orthodontic treatment using digital subtraction radiography (DSR) and to investigate possible contributing parameters. Methods: The subtracted images of panoramic radiographs of 21 patients before and after orthodontic treatment were evaluated using I/RAS C and Image J software. The retrieved data were analyzed by means of SPSS statistical software, and the method’s error was assessed. Results: There was a small but significant decrease of the root dimensions of the maxillary central incisors at the end of orthodontic treatment. The amount of root resorption was not significantly influenced by sex, age, dentition, malocclusion classification, extraction, overjet, overbite, elastic wear, and number of teeth with resorption as measured by DSR. Conclusion: DSR of pre- and posttreatment panoramic radiographs was able to confirm minor root resorption of the maxillary central incisors after orthodontic treatment. World J Orthod 2010;11:142–152.