Lower facial third projection: Analysis using true vertical lines from subnasale and soft Nasion

Orthognathic surgery is essential for correcting certain malocclusions and enhancing facial aesthetics. However, determining the ideal positioning of facial structures remains a topic of debate. This study aims to propose numerical references for surgical planning by determining the optimal sagittal projection of the maxillary incisors in aesthetically attractive Caucasian patients. An observational and retrospective study was conducted using cephalometric and photographic records of 89 patients' lateral profiles. These images were evaluated on a 10-point scale by orthodontists, maxillofacial surgeons, and laypeople. Cephalometric parameters were measured, including the position of the upper incisor and soft tissue pogonion, using the Barcelona Line and true vertical lines from subnasale. Statistical analyses were applied to explore the relationship between these parameters and aesthetic perception. The upper incisor and soft pogonion positions were found to significantly influence aesthetic perception. Ideal projection values for the upper incisor were 2.38 mm anterior to the Barcelona Line. The ideal projection for the soft pogonion was 6.02 mm anterior to the same reference. The positions of the upper incisor and soft pogonion are key predictors of aesthetic perception in orthognathic surgery. These findings may enhance surgical planning, although other factors may also affect facial aesthetics.