Characterizing the Abutment Prosthetic Support Interface of a Hybrid Abutment In Vitro for Single and Partial Fixed...

To investigate the resistance, retention, and prosthetic adaptability of an abutment prosthetic support interface (APSI) for single and splinted implant restorations.

Twenty-five 3 mm hexagonal-tapered hybrid abutments were subjected to fatigue testing to evaluate resistance of cemented metal crowns, applied on-axis and off-axis. Crowns of three different heights, 10 mm, 12 mm, and 14 mm were assessed. Retention was evaluated via dislodgement force testing for two configurations, single crowns (n=5) cemented on five 3 mm-high hybrid abutments and five 6 mm-high 8° tapered abutments; and splinted two-unit prostheses (n=10) cemented on two 3 mm-high hybrid abutments and two 3 mm-high 8° tapered abutments, both arranged in converging implant configurations.

All resistance specimens subjected to axial loading survived 1 million cycles. Off-axis loading resulted in implant body fractures in all specimens for 12 mm and 14 mm crown heights. Mean number of cycles to failure was 320,117 ± 114,230 for the 12 mm group and 137,375 ± 144,420 for the 14 mm group. Mean dislodgment forces of single crowns cemented on 3 mm-high hybrid abutments compared to 6 mm-high 8° tapered abutments were significantly different (p<0.05). Splinted prostheses on 3 mm-high hybrid abutments compared to 3 mm-high 8° tapered abutments were significantly different (p<0.001).

The APSI (hybrid abutment) concept demonstrated: (1) a cemented crown-abutment interface strength exceeding the inherent strength of the titanium implant material; (2) significantly greater cemented crown retention compared to tapered abutments; and (3) rotational adaptability, enabling optimized insertion paths for splinted restorations.