Load-Bearing Capacity of Custom-Made Versus Prefabricated Commercially Available Zirconia Abutments

Purpose: To compare the load-bearing capacity of custom-made zirconia abutments with that of prefabricated commercially available zirconia abutments. Materials and Methods: Zirconia (ICE Zircon) blocks were manually copy-milled to abutments using prefabricated commercially available abutments as models, divided into four groups (n = 10/group), and sintered at 1,500°C. Prefabricated commercially available abutments were used as controls (groups 1 and 4, n = 10/group). The abutments in the study groups were: (1) Astra ZirDesign (AstraTech); (2) copy-milled Zirkonzahn-Astra; (3) copy-milled Zirkonzahn-Astra, short; (4) Xive Cercon (Dentsply/Friadent); (5) copy-milled Zirkonzahn-Xive; and (6) copy-milled Zirkonzahn-Xive, modified. Seven abutments per group were screwed onto implant replicas (size 3.5/4.0 mm for AstraTech, 3.8 mm for Dentsply Friadent) with acrylic resin sample base; the implants were loaded dry with a universal testing machine at room temperature and a 45-degree loading angle. Statistical analyses were made using one-way analysis of variance. The three remaining abutments per group were screwed onto implant replicas, and the distance between the replica and the abutment was measured with a scanning electron microscope. Results: Significant differences were seen among the groups in terms of load-bearing capacity; copy-milled Zirkonzahn-Xive modified abutments (group 6) were statistically significantly stronger (1,099 N) than the other abutments (P .05). The Xive models resulted in catastrophic failure, whereas the Astra-design revealed visual bending before failure. Conclusions: Custom-made zirconia abutments have comparable failure loads to those seen for prefabricated commercially available zirconia abutments. Keywords: custom-made abutment, dental abutment, load-bearing capacity, marginal fit, zirconia