Sintered Characteristics of 3 Mole% Yttria-Stabilized Zirconia Polycrystals (3Y-TZP) Implants Manufactured by Slip-Casting and Computer Aided Design/Computer Aided Manufacturing (CAD/CAM).

Two types of dense and toughened 3Y-TZP zirconia implants were fabricated by the sintering of green compacts. Then, the sintered properties of the two implants were compared. Slip-cast and post-sintered all-ceramic zirconia implants were fabricated by the heat treatment at 1450 °C for 2 h using optimal slurry conditions (60 wt% solid content, 1 wt% dispersant, and pH 12). Computer-aided design and manufacturing (CAD/CAM)-machined and post-sintered zirconia crowns, supplied by a dental hospital, were obtained by sintering at 1650 °C for 5 h. The X-ray diffraction results indicated that the phase composition of the slip-casted specimen was completely tetragonal, but the CAD/CAM machined sample was composed of mixed phases of main tetragonal and minor monoclinic crystals. The sintered density and Vickers hardness of the slip-casted specimen were 6.07 g/cm³ and 1367 Hv, respectively, and these were higher than those of the CAD/CAM machined specimen. From the comparative results of the surface microstructure, hardness, and roughness between the two sintered specimens, the slip-casted specimen was found to have higher surface roughness and mechanical hardness, smaller grain size, and less surface micro-cracks than the CAD/CAM machined specimen.