Finite Element Analysis of Implant-embedded Maxilla Model from CT Data

Objectives: Finite element analyses (FEAs) of maxillary segment models with implants have been previously performed. However, there are no entire maxillary models available, as a base of reference for the size, boundary and load conditions of such models. Thus, the objectives of this study were to create an entire maxillary FEA model and to investigate stress distribution around a posterior implant embedded in it as a reference for further models.

Methods: CT images (DICOM data) of the entire maxilla were taken from a human dried skull and then converted into STL files, using 3D DICOM viewer (INTAGE Realia Professional). These files were imported into CFD software (ANSYS AI environment) and a cylindrical implant of 4.1-mm diameter and 8-mm length was computer-generated and overlapped over the right maxillary alveolar ridge approximately at the location of the first molar. This model was meshed with about 30,000 elements and about 15,000 nodes, and its material properties were defined. The model was then exported to a finite element program (ANSYS version 11.0), in which equivalent (von Mises) stresses were calculated.

Results: High stress concentrated around the implant neck. Moderate stress was found in the posterior region of the right alveolar crest, in the ipsilateral sinus floor around the implant apex and in the medial sinus wall.

Conclusion: By this method, an implant-bone FEA model that closely approximated the complicated structure of the entire maxilla could be generated. Stress from the implant mainly dispersed to the posterior region of the alveolar crest and ipsilateral sinus. Thus, a maxillary segment that includes these structures may be an appropriate substitute for the entire maxillary model.