Convergence Study of Three-Dimensional Upper Skull Model: A Finite Element Method

Le-fort I osteotomy has been widely used by maxillofacial surgeons as a procedure due to its versatility and simplicity to treat patient with dentofacial deformity. Technology such as virtual planning software has greatly aided surgeon to prepare for the surgery by allowing them to work with clinical engineer to plan for the surgery and create custom implants design on the patient’s scanned anatomy in form of three-dimensional (3D) model. Most of convergence study for skull was done by analyzing the total number of mesh elements. Hence, this study was conducted to determine the optimum mesh size by performing mesh convergence study using h-refinement method on the upper skull 3D model. The 2D Computed-Tomography (CT) images in DICOM format were used to create the 3D model by using Mimics software. The mesh refinement process of the segmented upper skull 3D model was performed in the 3-Matic software, and the mesh size used from 5 mm to 2.5 mm with 0.5 mm interval. Marc Mentat software was used to perform finite element analysis (FEA) where a fixed load was set on superior part of the skull meanwhile point load with 125N stress was applied on incisors. Results from the mesh convergence analysis showed that percentage difference of upper skull of 4.0 mm–3.5 mm mesh size is below 5% and from the convergence plot the line graph start to converge at 3.5 mm to 4 mm. Therefore, it can be concluded that 4 mm mesh size is the optimum mesh size for upper skull 3D model.