Résumé
Abstract Introduction Lips play a fundamental role in facial attractiveness and in decisions pertaining to orthognathic surgery. Objective To assess the upper lip changes following Le Fort I osteotomy for maxillary advancement and/or impaction. Methods In the present retrospective non-randomized clinical trial, we evaluated 3 groups of patients who underwent Le Fort I osteotomy of the maxilla. Group 1 (n = 35) underwent maxillary advancement, group 2 (n = 14), maxillary impaction, and group 3 (n = 11 ) was submitted to both maxillary advancement and impaction. The lip thickness of all patients was measured preoperatively, and the participants in each group were categorized into two subgroups: thin (< 12 mm) and thick (> 12 mm) lip. The primary (before orthognathic surgery) and final (after orthodontic bracket removal) lateral cephalograms of the patients were analyzed using the Dolphin software. Comparisons were made using the paired t-test and linear regression in the IBM SPSS Statistics for Windows software. Results The length of the upper lip increased by 1 mm (p = 0.012) on average following maxillary advancement, and it decreased by 0.43 mm (p = 0.24) on average following maxillary impaction. In the maxillary advancement group, the change in angulation of the incisors predicted the incisal display (p = 0.03). In the maxillary impaction group, skeletal changes in the vertical dimension predicted changes in upper lip length (p = 0.033). Conclusions Le Fort I osteotomy for maxillary advancement significantly increases the length of the upper lip. The assessment of lip thickness prior to surgery can help