Comparison of Biomechanical Behavior Between Commercial and Patient-Specific TI6AL4V Titanium Plates of the Same Design Following Le Fort I Osteotomy: A 3D- Finite Element Analysis

Abstract

AbstractBackground:Le Fort I osteotomy is a common orthognathic procedure for treating patients with midface skeletal abnormalities. This study evaluates and compares the biomechanical behavior between the three-dimensional (3D) printed patient-personalized TI6AL4V mini plates with commercially made pure mini plates of the same size and design using finite element analysis.Methods:Le Fort I osteotomy with 5 mm advancement associated with mediolateral rotation of the maxilla on the sagittal plane creating a gap of 3 mm at the most posterior part of the left side model was virtually executed on 3D-model using Mimics software. Fixation methods were modeled using (software) to represent 3D-printed patient-personalized TI6AL4V and commercially titanium mini plates. Both fixation mini plates models had the same conventional 4-hole L-shape design with similar thicknesses of 0.5 mm and 0.7 mm and placement vectors at the piriform rims and the zygomaticomaxillary buttress, respectively. ANSYS R19.2 software (Canonsburg, Pennsylvania, U.S.) was employed to create computer-aided engineering finite element models and analyses. Stress distribution, strain behaviors, and displacements of the fixation mini-plates, total model, and the maxilla segment were analyzed after loading postoperative occlusal force of 125, 250 and 500 N/mm².Results:Le Fort I fixation with TI6AL4V L-shaped mini plates resulted in lower principal VM stress, strain, and displacement values than commercially made titanium L-shaped mini plates. The TI6AL4V fixation demonstrated a reduced displacement of the maxillary segment. Both fixation models showed the maximum VM stress, strain, and displacement values across the area where a vertical gap between the bony segment of the maxilla was created due to the downward rotation creating a posterior gap of 3mm at the left side of the maxilla. The maximum overall VM stresses of TI6AL4V mini plates were relatively higher than those observed in the commercial titanium mini plates.Conclusion:The maximum stress, strain, and segment displacement of both fixation models were predominantly concentrated in the area of the vertical gap. Notably, both fixation materials exhibited remarkably close values, which can be attributed to the similar design of the fixation plates used in both models.