Fatigue Lifetime of Zygomatic Implant-Supported Maxillary Prosthesis: A Finite Element Analysis

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Purpose: To use finite element analysis (FEA) and computerized lifetime prediction algorithms to evaluate the biomechanical behavior and fatigue lifetime of a full-arch maxillary prosthesis supported by two conventional implants and two zygomatic implants in both hybrid and quad designs.Methods: A commercially available titanium zygomatic implant system, a commercially available titanium conventional dental implant system, and a standardized sawbone human skull model were scanned using micro-computed and cone-beam computed tomography.Three dimensional (3D) models were created in Mimics.Advanced maxillary atrophy was determined on the human skull and simulated using 3D segmenting and editing tools.Finite element volume meshing was completed in Simpleware, then exported to ABAQUS where material characteristics were assigned to each respective part.The following three occlusal load scenarios were considered in this study: 1.) 150 N uniformly distributed; 2.) 150 N in the anterior region and 250 N in the posterior region; 3.) 178 N in the anterior region and 489 N in the posterior region.The von Mises stresses for each design were analyzed and plotted, and the static results were used to predict the fatigue lifetime of the zygomatic implants in FE-Safe. Results:The maximum von Mises stress in the surrounding bone tissue was located in the crestal bone at the sites of zygomatic implants.For zygomatic implants, the maximum von Mises stress was in the abutment connection area.All values were within the bone resorption thresholding values and the limit of material strength.The fatigue lifetime for the zygomatic implants in the hybrid zygomatic implant-supported prosthesis was predicted as 1.937E+14 cycles under the maximum loading for this study.The quad-based zygomatic implant system had a lifetime prediction of 2.08E+14 chewing cycles under maximum loading.Conclusion: Peak static stresses were found in the abutment connection of zygomatic implants and crestal bone surrounding the zygomatic implant.Therefore, additional concern should be placed on these areas, for they are most likely to fail first.The fatigue lifetime predicted for the titanium zygomatic implant in each given scenario using FE-based lifetime prediction exceeded the prediction of 40 years of service time.