 5. All subjects had good oral hygiene. The exclusion criteria in this study was as follows; 1- Missing permanent teeth with exception of 3rd molar. 2- Previous orthodontic treatment. 3- Systemic disease that may influence orthodontic treatment and drug intake. 4- Periodontal disease. 5- Functional mandibular deviations and facial asymmetry. 6- History of parafunctional habits. 