Three-Dimensional Finite Element Modeling of an Implant-Supported Fixed Dental Prosthesis

Objectives: To describe a three-dimensional finite element modeling protocol for an all-ceramic implant-supported fixed dental prosthesis using Simpleware and micro-CT data.
Methods: Two titanium dental implants (Astra Tech Osseospeed, Ø 4.0 and 4.8 mm, Dentsply), their suitable zirconia abutments, and a three-unit all-ceramic fixed dental prosthesis were scanned using an X-ray micro-CT scanner (Skyscan1172, Micro Photonics). Sliced images from all components were generated at a resolution of 34.4 µm, reconstructed by NRecon software (Micro Photonics), and processed into 3D models using an interactive medical image processing software (Simpleware, Synopsis). Individual masks of all components (implants, abutments, and prosthesis) were produced by thresholding tools based on their greyscale values. 3D editing and Boolean Operations tools were used to correct artifacts and imperfections, and to generate new features. The connector heights of the ceramic prosthesis were altered to create new models for future analysis. A cuboid mask was created to simulate the bone. All models were converted to surfaces, assembled, and meshed together to be exported and analyzed subsequently by a finite element analysis software (ABAQUS, Simulia).
Results: The final models were composed of two implants and their abutments, one multi-layered all-ceramic fixed dental prosthesis, filling, cement layer, and simulated bone. The models created by 3D modeling had good and detailed physical resemblance compared with the physical components scanned. The connector heights were successfully altered (3, 4, and 5 mm) to further investigate connector height's influence on the biomechanical behavior of the protheses.
Conclusions: The combined use of micro-CT scan and Simpleware software provided an accurate, reliable, and non-destructive method to create the digital models and test the biomechanical behavior of all-ceramic implant-supported fixed dental prosthesis with different features.