This randomized split-mouth clinical trial aims to compare the accuracy and clinical outcomes of CAD/CAM 3D-printed surgical guides with the conventional free-hand technique for orthodontic miniscrew placement in the posterior maxilla. Each participant will receive miniscrew placement using both techniques on opposite sides of the maxilla following random allocation. The primary outcome is placement accuracy assessed by three-dimensional positional and angular deviations between planned and actual miniscrew positions. Secondary outcomes include miniscrew stability, success rate after three months, postoperative pain, procedural time, patient satisfaction, and complications. The study also evaluates maxillary posterior cortical bone thickness using cone-beam computed tomography (CBCT) and investigates its relationship with miniscrew placement accuracy and stability