Objective    To investigate the application of computer-aided 3D reconstruction and rapid prototyping (RP) technique in the correction of prominent mandibular angle.     Methods    Computer tomography scanning and 3D reconstruction were performed on 15 square face patients with prominent mandibular angles

then their actual mandible models were made by RP techniques. Surgical programs were made according to the model

including partial mandibular angle osteotomy

outer mandible table sagittal splitting osteotomy

chin augmentation with autogenous mandibule bones

and so on. In 15 cases

mandibular angle partial cutting was performed in 5 cases

sagittal splitting osteotomy in 6 cases

and mandibular angle partial cutting combined with splitting osteotomy in 4 cases. The autogenous mandibule bones were transplanted for chin augmentation in 3 chin microsomia patients. All the cases were treated according to the position and range set by the RP model.     Results    All the mandibular models produced by RP techniques were real and complete

which could directly and precisely show the state of the mandible. The operations completed smoothly and accomplished with the expected outcomes designed before operation. In all cases

the width of lower face was efficiently reduced and the face was symmetrical after operation. The follow-up period ranged from 3 months to 1 year in 12 patients

during which their facial appearances were in good condition and the results were satisfactory.     Conclusion    RP techniques is helpful in precise representation of the state of mandible

which providing ideal surgical models for accurate evaluation of prominent mandibular angle

design of surgical procedures as well as surgery instruction. It can provide good assistance to facial contour plastic surgery.