Objective: Assessment of maxillary buccal alveolar bone following orthodontic alignment without extractions.(Cone beam study). Materials and Methods:Twenty adolescents with crowded permanent dentitions were treated without extractions with EASY SMILE (USA) Orthodontic self-ligating bracket brackets & conventional brackets. Cone beam computed tomographic scans were taken before treatment (T0) and after alignment (T1). Alveolar bone thickness (BT) was evaluated at the maxillary central incisor (I), second premolar (2PM), and first molar mesiobuccal (mb1M) and distobuccal (db1M) roots. Correlations between alveolar width changes and initial arch width, initial crowding, amount of expansion, amount of tipping, and amount of molar rotation were calculated were calculated. All data collected will be tabulated and statistically analyzed. Results:BT decreased and BH increased significantly for the incisors and mesiobuccal(mb1M) root of the first molars. Also, arch dimensions generally increased together with tipping. Bone loss was correlated with crowding and amount of expansion in the premolar region. Conclusion:Nonextraction alignment resulted in arch expansion associated with tipping of teeth for both self-ligating brackets & conventional brackets. Alignment with expansion led to horizontal and vertical bone loss at the incisors and mesiobuccal root of the first molars. Thinner BTs and more severe crowding before treatment led to increase the risk for buccal bone loss. Keywords:Alveolar bone,CuNiTi wire,CBCT,Self-ligating