Abstract Objectives Smile aesthetics are crucial in orthodontic and orthognathic planning, particularly for patients with dentofacial deformities seeking enhanced facial harmony. This study evaluated changes in smile parameters of patients with class III deformities before and after orthognathic surgery using 3D stereophotogrammetry. Materials and methods Conducted at Başkent University Oral and Maxillofacial Surgery Department, this retrospective investigation comprised 21 patients with class III skeletal deformities who underwent bimaxillary orthognathic surgery. Standardized social-smile photographs and 3D facial scans were obtained preoperatively and at an average 8-month follow-up. Smile parameters, including buccal-corridor ratio, upper-lip length, inter-commissural width, lip thickness, lip asymmetry and volumetric measures were reported. Preoperative and postoperative differences were analyzed with paired T-tests or Wilcoxon signed-rank tests ( p < 0.05), 95% confidence intervals, and Cohen’s d for paired samples. Results Mean follow-up was approximately 8 months. False-discovery-rate correction identified one significant change: buccal-corridor ratio decreased by 4.4%, producing a visibly fuller transverse smile ( d = 0.66). Upper-lip length and inter-commissural width increased by about 1.0 mm and 1.6 mm, respectively (both d ≈ 0.5). Vertical smile dimensions, incisor display, and global facial height and width remained stable (| d |≤0.18). Measurement reliability ranged from good to excellent (ICC = 0.60–0.93(Intraclass Correlation Coefficient). Conclusion Orthognathic surgery improved transverse smile fullness in patients with class III skeletal deformities while preserving vertical dental display, affirming the value of 3D assessment. Clinical relevance Three-dimensional stereophotogrammetry offers objective, reproducible documentation of soft-tissue changes and should be integrated into routine orthognathic evaluations. Unlike previous studies relying on cephalometry and photographs, this is the first study to utilize 3D stereophotogrammetry for assessing smile parameters.
Enez et al. (Tue,) studied this question.