The purpose of this study was to evaluate the effect of two different mandibular En Masse retraction techniques using mandibular buccal shelf miniscrews. Twenty patients with skeletal Class I or mild skeletal Class II relationship and severe crowding in the lower arch more than 7 mm requiring orthodontic treatment with upper anterior en masse retraction in the extraction space of first premolars were selected then 10 patients will be allocated to each group. The CBCT were analyzed for differences between pre-treatment and post-treatment variables that included skeletal and dental relationships. Results were statistically analyzed by IBM SPSS version 28. There were no significant differences in bone resorption of the labial bone and its height after performing both techniques of En masse retraction (P values<0.001). the bone remodeling process is required for tooth displacement.