External apical root resorption is a possible side effect of fixed orthodontic treatment, particularly in the upper front teeth. This randomized clinical trial was conducted to compare the amount and timing of root resorption associated with three different methods of retracting the upper anterior teeth using miniscrew anchorage. Sixty adult patients with Class II Division 1 malocclusion who required extraction of the upper first premolars were randomly allocated to one of three groups: a bidimensional bracket group, a hybrid dual-section archwire group, or a conventional sliding mechanics group. In all groups, the six upper anterior teeth were retracted together with the support of orthodontic miniscrews. Panoramic radiographs were obtained before treatment, after completion of leveling and alignment, and after completion of en-masse retraction. Root and crown lengths were measured on these radiographs to estimate external apical root resorption during the leveling and alignment phase, during the retraction phase, and over the complete observation period. The study also compared the pattern of resorption among the upper canines, lateral incisors, and central incisors.