Date of Award



Department of Orthodontics

First Advisor

Jonas Bianchi


Introduction: The objective of this retrospective longitudinal study was to assess and compare the surgical changes and stability of the maxilla, mandible, and mandibular condyle, in patients who have undergone surgery first approach (SFA) followed by conventional braces or Invisalign (Inv) treatment. Methods: Thirty patients had a cone beam computed tomography (CBCT) exam taken at three timepoints: T1 (presurgery), T2 (immediately after surgery), and T3 at the completion of orthodontics treatment. After the cranial base registration, twenty-seven landmarks were located on each time point using axial, sagittal, and coronal cross-sectional views in the ITK-SNAP software. In addition, seventeen skeletal angular and linear variables were measured using the 3D Slicer software. Result: In general, both Groups had similar sugical changes (T2-T1) and stability (T3-T2). There was a statistically significant longer postsurgical orthodontic time in the Fixed Group (x̅ = five months). Skeletally, comparing T3-T2 the B point showed a statistically significant inferior position in the Fixed Group compared to the Inv Group (1.3 mm), resulting in a larger increase in mandibular plane angle in the Fixed Group (x̅ = 2.7 degrees). Conclusion: The Fixed appliances and clear aligner therapy in the surgery first approach resulted in similar skeletal changes and stability, except for the mandibular plane angle, which showed a greater increase in the Fixed Group. This result may suggest that patients with hyperdivergent skeletal pattern could benefit from aligner therapy for the postsurgical orthodontic phase.