Abstract: Objective: To evaluate facial soft tissue 3-deminsion changes of skeletal Class Ⅲ malocclusion patients after orthognathic surgery using structure light scanning technique. Methods: Eight patients ［3 males and 5 females, aged (27.08±4.42) years］ with Class Ⅲ dentoskeletal relationship who underwent a bimaxillary orthognathic surgical procedure involving advancement of the maxilla by Le Fort Ⅰ osteotomy and mandibular setback by bilateral sagittal split ramus osteotomy (BSSO) and genioplasty to correct deformity were included. 3D facial images were obtained by structure light scanner for all the patients 2 weeks preoperatively and 6 months postoperatively. The facial soft tissue changes were evaluated in 3-dimension. The linear distances and angulation changes for facial soft tissue landmarks were analyzed. The soft tissue volumetric changes were assessed too. Results: There were significant differences in the sagittal and vertical changes of soft tissue landmarks. The greatest amount of soft tissue change was close to lips. There were more volumetric changes in the chin than in the maxilla, and fewer in the forehead. Conclusion: After biomaxillary surgery, there were significant facial soft tissue differences mainly in the sagittal and vertical dimension for skeletal Class Ⅲ patients. The structure light 3D scanning technique can be accurately used to estimate the soft tissue changes in patients who undergo orthognathic surgery.

Key words: Malocclusion, Angle class Ⅲ, Imaging, three-dimensional, Face, Structured light