Influence of Conventional and Innovative Abutment Designs and Retention Mechanisms on the Biomechanics and Microgap Pattern: A 3D Finite Element Analysis

This study aimed to analyze the biomechanics of three abutment systems with distinct retention mechanisms and their impact on the implant-abutment interface (IAI). The finite element analysis method was used to model maxillary three-unit restorations with conventional cement-retained abutment (CRA), multi-unit abutment (MUA), and innovative cementless link-retained abutment (LRA) systems. Dental implants were positioned at 0°/0°, 15°/15°, and 25°/25° angulation combinations. Analyses were performed under 400 N vertical and 200 N oblique loading applied at a 45° angulation. The LRA system exhibited lower stress on the implants and abutments under both loading conditions, whereas the CRA system demonstrated the highest stress. In contrast, the maximum principal stresses within the peri-implant bone were the highest in the LRA system under both loading conditions. Despite greater IAI displacement in the molar region, no specific abutment system exhibited distinct superiority under different scenarios. Overall, an increase in implant angulation led to higher stress values across all parameters. The MUA and LRA systems demonstrated reduced stress concentration and more uniform load distribution compared with the CRA system under tilted implant configurations. The findings suggest that the innovative cementless LRA system may serve as a feasible alternative to conventional CRA and MUA systems, exhibiting superior biomechanical performance, particularly compared with the CRA system.