Objectives: The purpose was to investigate the potential difference in the load-to-fracture values of several all-ceramic crown systems. Five different coping-reinforced all-ceramic crown systems were selected. Ten crowns from each system were fabricated and luted to standardized titanium dies.
Methods: The study consisted of five groups of ten samples each, all luted using G.C. Link Max resin adhesive cement. Group A: IPS Eris, Group B: Cerac In-lab Alumina coping, Group C: Cerac In-lab Zirconia coping, Group D: Procera AllCeram Alumina coping, and Group E: Procera Zirconia coping. Following cementation, the samples were placed under a 5 Kg static load for 10 minutes insuring proper seating and stored in 100% humidity for one week. All samples were visually inspected prior to testing and were loaded to fracture at the rate of 0.5 mm/min using a universal-testing machine.
Results: Group A = 321.49 KgF +/- 113.69 (S.D.), Group B = 288.63 +/- 102.82 (S.D.), Group C = 266.58 +/- 69.17 (S.D.), Group D = 295.49 +/- 80.54 (S.D.), and Group E = 420.37 +/- 82.45 (S.D.). The data were analyzed using an unpaired t-test; this indicated a statistical difference between group E and all of the others (P-value =0.039).
Conclusions: We concluded under these conditions, the Procera Zirconia crown system has significant higher load-to-fracture value than several other all-ceramic crown systems.