Evaluation of Soft Tissue Changes in Skeletal Class III Patients After Bimaxillary Orthognathic Surgery with StereophotogrammetryBackground: To examine the changes after bimaxillary orthognathic surgery in soft tissues of patients with skeletal Class III malocclusion using three-dimensional (3D) photographic imaging. Methods:This study was conducted on 28 patients, 11 female, 17 male, who treated with one-piece Le Fort I in the maxilla along with bilateral sagittal split osteotomy in the mandible in Erciyes University Faculty of Dentistry Department of Orthodontics ( mean age 20.4 ± 3.01, range 17. 03 -31.16). While the maxillary advancement amount was 4.70 ± 1.20 mm; impaction amount was 2.23 ± 0.97 mm. The amount of mandibular set-back was 4.23 ± 1.56 mm. 3D stereophotogrammetric recordings were taken just before and at least 6 months after the operation. The data were evaluated as a single group, as no difference was observed between genders. "paired t test" was used for statistical analysis.Results: In the sagittal direction, maxillary lengths, mandibular convexity angle, soft tissue A and ANB angles increased statistically significantly. The maxillary convexity angle, mandibular lengths and corpus lengths, facial convexity angle, total facial convexity angle and soft tissue B angle were statistically significantly decreased. In the transverse direction, nasal and nasal base widths increased statistically significantly. In the vertical direction, maxillary height, upper vermilion height, the ratio of mid-face height to lower face height increased statistically significantly, lower vermillion height, lower lip length, mandibular height, mid and lower face heights, anterior face height, vertical and mentolabial angles were statistically significantly decreased. Conclusion:As a result of orthognathic surgery treatment, the most prominent changes were observed in sagittal, the slightest changes in transversal direction measurements. This study may be useful in predicting postoperative soft tissue changes and to what extent patient's expectations can be satisfied in skeletal Class III patients after bimaxillary orthognathic surgery.