In vitro fracture resistance of implant-supported terminal zirconia cantilevered frameworks

This study aims to investigate the in vitro fracture loads of three different terminal cantilever forms of implant-supported zirconia frameworks. A total of 30 implant-supported zirconia frameworks (Aconia, China) were CAD/CAM-fabricated and divided into three groups, each with a distal abutment cantilever form design of 5mm: Group A had square cantilevers, Group B had oval cantilevers, and Group C had oval-square cantilevers. Universal testing machine was used to apply vertical loads to the samples, and the fracture loads were recorded. Variance analysis and Tukey's post-hoc tests were applied for statistical evaluation. There was no significant difference between the mean fracture loads of Group B (587.8±112.2 N) and Group C (591.3 ±81.3 N), but both of these groups exhibited significantly lower fracture loads compared to Group A (893.8±145 N, p<0.001 for each). Within the scope of this experimental study, it can be concluded that implant-supported terminal square shaped cantilever zirconia frameworks, each measuring 5 mm from the distal abutment, are more likely to exhibit greater resistance to vertical loads compared to their oval and oval-square counterparts.