IADR Abstract Archives
Effect of Luting Agents on Fracture Load of Zirconia Crowns
Objectives: The aim of this study was to evaluate the effect of luting agents on the load at fracture and fracture mode in monolithic zirconia crowns with two different material compositions. A 3Y-TZP zirconia with 4-6wt% Y2O3 and a 5Y-TZP zirconia with ≤12wt% Y2O3.
Methods: A total of 60 monolithic zirconia crowns, 40 3Y-TZP crowns (Prettau®Zirconia, Zirkonzahn) and 20 5Y-TZP zirconia crowns (Prettau® 4 Anterior®, Zirkonzahn) were produced to a shallow chamfer molar preparation. The 3Y-TZP crowns were divided into four groups (n=10) and attached to abutment duplicates (SDR® flow+, Denstply Sirona Restorative) using the following four different cementation techniques; 1: Self-adhesive resin cement (RelyX™ Unicem, 3M ESPE), 2: Pre-treatment of the crown with sandblasting and self-adhesive resin cement, 3: Zinc phosphate cement (Harvard Cement OptiCaps®, Harvard Dental International GmbH), 4: Glass ionomer cement (GC Fuji® I CAPSULE, GC Corporation). The 5Y-TZP crowns were divided into two groups (n=10) and attached to the duplicates with; 1: Self-adhesive resin cement, or 2: Sandblasting pre-treatment and self-adhesive resin cement.
All the crowns were loaded axially on the occlusal surface in a servo hydraulic testing system at a rate of 0.5mm/min until fracture occurred. Fracture analysis of the fractured specimen was performed.
Results: The 3Y-TZP zirconia crowns fractured at significantly higher values than that of the 5Y-TZP (p<0.005). The median load at fracture for the 3Y-TZP crowns was 5747N (3873N-7500N), and 3082N (2100N-4948N) for the 5Y-TZP crowns. There were no significant differences among different cementation techniques within each material group.
All fractures initiated at the crown margin, at either the mesial or distal curvature, and propagated towards the occlusal surface, resembling clinically observed fractures.
Conclusions: The 3Y-TZP zirconia crowns fractured at almost twice the load compared to the 5Y-TZP zirconia crowns, but neither were affected by cementation technique.
Methods: A total of 60 monolithic zirconia crowns, 40 3Y-TZP crowns (Prettau®Zirconia, Zirkonzahn) and 20 5Y-TZP zirconia crowns (Prettau® 4 Anterior®, Zirkonzahn) were produced to a shallow chamfer molar preparation. The 3Y-TZP crowns were divided into four groups (n=10) and attached to abutment duplicates (SDR® flow+, Denstply Sirona Restorative) using the following four different cementation techniques; 1: Self-adhesive resin cement (RelyX™ Unicem, 3M ESPE), 2: Pre-treatment of the crown with sandblasting and self-adhesive resin cement, 3: Zinc phosphate cement (Harvard Cement OptiCaps®, Harvard Dental International GmbH), 4: Glass ionomer cement (GC Fuji® I CAPSULE, GC Corporation). The 5Y-TZP crowns were divided into two groups (n=10) and attached to the duplicates with; 1: Self-adhesive resin cement, or 2: Sandblasting pre-treatment and self-adhesive resin cement.
All the crowns were loaded axially on the occlusal surface in a servo hydraulic testing system at a rate of 0.5mm/min until fracture occurred. Fracture analysis of the fractured specimen was performed.
Results: The 3Y-TZP zirconia crowns fractured at significantly higher values than that of the 5Y-TZP (p<0.005). The median load at fracture for the 3Y-TZP crowns was 5747N (3873N-7500N), and 3082N (2100N-4948N) for the 5Y-TZP crowns. There were no significant differences among different cementation techniques within each material group.
All fractures initiated at the crown margin, at either the mesial or distal curvature, and propagated towards the occlusal surface, resembling clinically observed fractures.
Conclusions: The 3Y-TZP zirconia crowns fractured at almost twice the load compared to the 5Y-TZP zirconia crowns, but neither were affected by cementation technique.
