ABSTRACT
PURPOSE: Orthognathic surgery has the objective of altering facial balance to achieve esthetic results in patients who have severe disharmony of the jaws. The purpose was to quantify the soft tissue changes after orthognathic surgery, as well as to assess the differences in 3D soft tissue changes in the middle and lower third of the face between the 1- and 2-jaw surgery groups, in mandibular prognathism patients. MATERIALS AND METHODS: We assessed soft tissue changes of patients who have been diagnosed with mandibular prognathism and received either isolated mandibular surgery or bimaxillary surgery. The quantitative surface displacement was assessed by superimposing preoperative and postoperative volumetric images. An observer measured a surface-distance value that is shown as a contour line. Differences between the groups were determined by the Mann-Whitney U test. The Spearman correlation coefficient was used to evaluate a potential correlation between patients' surgical and cephalometric variables and soft tissue changes after orthognathic surgery in each group. RESULTS: There were significant differences in the middle third of the face between the 1- and 2-jaw surgery groups. Soft tissues in the lower third of the face changed in both surgery groups, but not significantly. The correlation patterns were more evident in the lower third of the face. CONCLUSION: The overall soft tissue changes of the midfacial area were more evident in the 2-jaw surgery group. In 2-jaw surgery, significant changes would be expected in the midfacial area, but caution should be exercised in patients who have a wide alar base.
Subject(s)
Face/anatomy & histology , Mandible/abnormalities , Maxilla/surgery , Orthognathic Surgical Procedures , Prognathism/surgery , Cephalometry , Cone-Beam Computed Tomography , Female , Humans , Imaging, Three-Dimensional , Male , Mandible/diagnostic imaging , Mandible/surgery , Maxilla/diagnostic imaging , Maxillofacial Development , Orthognathic Surgical Procedures/methods , Osteotomy, Le Fort , Osteotomy, Sagittal Split Ramus , Statistics, Nonparametric , Young AdultABSTRACT
PURPOSE: The objective of this study was to evaluate the three-dimensional soft tissue changes observed over time after bimaxillary surgery for mandibular prognathism using cone-beam computed tomography (CBCT) superimposed imaging. MATERIALS AND METHODS: CBCT scans were obtained for 25 patients before bimaxillary surgery (T0), at 2 months after surgery (T1) and at 6 months after surgery (T2). Cephalometric variables from the reoriented volumetric images were measured and compared at T0, T1, and T2. The quantitative surface displacement in the middle and the lower third of the facial soft tissue using CMF tools was assessed by superimposing the T0 and T1 or T0 and T2 3D images. RESULTS: The soft tissue in middle third of face moved forward at T1 and significantly moved backward from T1 to T2 (Ch-Al, p < 0.001; Al, p < 0.05; Pn, p < 0.05). Most of the soft tissue changes from T1 to T2 were not correlated with the hard tissue changes (p > 0.05), while the cheeks were positively correlated with the soft tissue around them (Exo-Al, p < 0.01; Ch-Al, p < 0.01). CONCLUSION: Post-operative soft tissue changes occurred in the middle third of the face and are considered to be more complex than the changes in the lower third of face. Therefore, soft tissue assessment at least 6 months after surgery is desirable.
