Implant-Supported Restoration with Straight and Angled Hybrid Abutments: Digital Image Correlation and 3D-Finite Element Analysis

Abstract

Objective: The aim of this study was to investigate the effect of the hybrid abutment with different angles (0 and 15 degrees) on the stress distribution and deformation on maxillary implant-supported fixed prosthesis, using digital image correlation (DIC) and finite element analysis (FEA). Materials and Methods: For DIC, two situations were considered: conventional straight implant placement and implant placement with 15 degrees inclination. Different zirconia mesostructures were milled, one straight and the other with a 15-degree angulation to correct the implant positioning. Then, the zirconia mesostructures were cemented to the titanium base (Ti base), and both groups received a lithium disilicate crown. The DIC technique was performed to measure the deformation generated on the simulated bone surface (150 N loading). For the FEA (in silico), three-dimensional numerical models based on the in vitro setup were modeled using computer-aided design software. All materials were considered elastic, isotropic, and homogeneous. Comparison of both methods showed coherence between the in vitro and in silico results. The von-Mises stress of the implants, Ti base and screw, and the maximum principal stress in the mesostructure and crown were calculated for both conditions. Results: The overall surface deformation distributions determined by both techniques were considered similar allowing the model validation. The higher deformation was found in the cervical region with a higher magnitude for the angled hybrid abutment. The same pattern was observed in the stress fields regardless of the analyzed region and structure. Conclusion: Based on this study, using an angled hybrid abutment to correct the implant positioning generated higher stress in the implant fixture, surrounding tissue, Ti base, screw, and crown. Therefore, the implant should be positioned axially, whenever possible, to reduce the mechanical complications.