Background: The present study was conducted for evaluating alveolar bone changes around mandibular incisors during surgical orthodontic treatment of patients with mandibular prognathism. Materials & methods: A total of 20 patients who presented with jaw deformities diagnosed as skeletal Class III mandibular prognathism. To evaluate the change of the surgical orthodontic treatment progress including alveolar bone around the lower incisors, lateral and frontal cephalograms and CBCT images were obtained before treatment (T0), after presurgical orthodontic treatment (T1), and after debonding (T2). A CBCT scanner was used to scan the patients while they were upright and with maximal intercuspation. All the results were assessed by SPSS software. Results:The lower central and lateral incisors demonstrated that, following presurgical orthodontic therapy, there was a reduction in the vertical alveolar bone level and the alveolar bone thickness of the labial and lingual plates; however, there was no degradation during the postsurgical orthodontic treatment. Conclusion: People with mandibular prognathism should receive extra consideration because excessive forward movement of the lower incisors during presurgical orthodontic therapy may result in alveolar bone loss surrounding the lower incisors. Key words: Alveolar bone