Biomechanical Behaviors of Implant-Supported Zirconia Restorations Cemented to Novel Screw-Retained Abutment Systems: A Three-Dimensional Finite Element Analysis Study

Abstract

Objective: The purpose of this study was to evaluate the biomechanical behaviors of non-engaging titanium base abutments (N-TiBA) bonded to three-unit zirconia restorations in terms of stress dis-tribution in implants and prosthetic components. Material and Methods: Three-dimensional (3D) models of a tissue-level and bone-level implant systems and their screw-retained abutments (SRA) and N-TiBA were created. A bone block representing the maxillary right posterior region was created, and the implants were placed in the first premolar and first molar areas. Six different three-unit implant-sup-ported fixed dental prostheses (I-FDPs) models were created: tissue-level implant, N-TiBA, 6 mm crown height (TL6); tissue-level implant, N-TiBA, 10 mm crown height (TL10); bone-level implant, SRA, 6 mm crown height (SR6); bone-level implant, SRA, 10 mm crown height (SR10); bone-level implant, N-TiBA, 6 mm crown height (BL6); bone-level implant, N-TiBA, 10 mm crown height (BL10). The restoration material was determined as monolithic zirconia. In each model, equal vertical (200 N) and oblique (100 N) loads were applied to each tooth simultaneously. The stress distribution in the restoration, implant, abut-ments, and basal screws was evaluated through the von Mises stress analysis. Results: The TL6 and TL10 exhibited higher von Mises stress values in the implants and lower von Mises stress values in the abut-ments than in the other FEA models. The increase in the crown height resulted in higher stress values under oblique loading compared to ver-tical loading. Conclusion: The non-engaging connection type and crown height affected the stress distribution in the implant and pros-thetic components.