Strategies for Designing 3D-Printed Titanium Plates for Orthognathic Surgery: Trade-off Between Biomechanical Compatibility and Fatigue Strength

Le Fort I osteotomy is an orthognathic surgery used to correct maxillofacial deformities. The maxilla is cut and can be repositioned using patient-specific titanium fixation plates. The aim of the study is to propose a workflow that exploits the numerical modelling of orthognathic case to obtain the optimization of plate design. The 3D model of a le Fort I case was reconstructed from the patient images to create a finite element model with occlusal and muscular forces. A numerical fatigue analysis was carried out using Matake and Fatemi-Socie criteria. The plate design was optimized minimizing the plate thickness to improve biomechanical compatibility and changing the fillet radius and the thickness in critical regions for fatigue life to ensure adequate fatigue strength. The post-optimized plates show a significant increase in the predicted endurance life, reaching the required limit of 150000 chewing cycles. This work confirms the effectiveness of the optimized plate design to ensure mechanical reliability and reduce the risk of complications and discomfort for the patient.