Comparison of implants placed in mandible and reconstructed fibula using finite element analysis

Abstract

Purpose: The purpose of this study was to compare dental implants placed in mandible and reconstructed fibula under the same loading conditions using three-dimensional finite element analysis.<br/> <br/> Materials and methods: Two three-dimensional finite element models were developed to analyze biomechanical behaviors of implants placed in mandible and reconstructed fibula. Mandible model was composed of the mandibular segment, implant systems, and two-unit splinted implant-supported crowns. Fibula model included the same components except that the mandible was replaced with a reconstructed fibula. In the implant-abutment joint with abutment screw, preload was achieved. Oblique loading of 150 N was applied to the occlusal surfaces of the splinted crowns at 11.54 degrees to apico-coronal direction. The stress distribution patterns and the maximum von Mises stress of the individual components were compared.<br/> <br/> Results: In the supporting bones, stress was concentrated in the cortical bone around the implant neck. After screw tightening and before the imposition of oblique loads, the pattern and values of the von Mises stresses were similar between the mandible and fibula models. The highest von Mises stresses in the cortical bone were 6.7 MPa in the mandible model and 7.1 MPa in the fibula model. After application of oblique loads, the highest von Mises stresses in the cortical bone were 11.5 MPa in the mandible model and 25.2 MPa in the fibula model. In the implant systems, the highest stress concentration was observed in the abutment screws in all models. After screw tightening and before the application of oblique loads, the stress distributions of the two models were similar to the ones before loading. The highest von Mises stresses in the abutment screws and abutments were 115.7 MPa in the mandible model and 115.1 MPa in the fibula model. After application of oblique loads, the maximum von Mises stress on the implants was 113.5 MPa in the mandible model and 116.2 MPa in the fibula model. <br/> <br/> Conclusion: Within the limits of this study, the splinted implant-supported fixed prosthesis placed in the reconstructed fibula might be a successful treatment option for the patient who underwent mandibular reconstruction based on biomechanical behaviors.<br/>