Inclusion Criteria:  Age range from 13 to 18 years. Full set of permanent teeth (the third molars are not considered). Angle class I malocclusion with normal facial proportions. Mild to moderate crowding in both arches that require treatment with fixed appliance using non extraction approach No previous orthodontic or orthognathic surgery treatment. Free from oral and general health problems that could interfere with orthodontic treatment.. All teeth should be caries-free.  Exclusion Criteria:  Patients with poor oral hygiene or periodontally compromised teeth. History of serious medical problems or taking systemic medication which could affect orthodontic treatment. History of serious dental problems (endodontic treatment, periodontal surgery, apicectomy, or any other dental problems) which could affect orthodontic treatment. History of trauma, bruxism, or or parafunctional habits.