Root Resorption and Alveolar Bone Changes in the Maxillary Canine Retraction Using Ni Ti Closed-coil Springs Versus Elastomeric Chains (A Split -Mouth Cone Beam CT Study)

* Inclusion Criteria: * Patients aged 16 years or older * Patients indicated for fixed orthodontic appliances * Patients indicated for bilateral extraction of maxillary first premolars * Patients who have not undergone any previous orthodontic treatment * Exclusion Criteria: * Patients with a history of craniofacial trauma, anomalies, or congenital defects * Patients currently taking anticoagulant drugs affecting bone metabolism * Patients with a history of trauma or pathology involving the maxillary canines * Patients with periodontally compromised teeth