###### Abstract
For better esthetics, high-transmittance zirconia with low alumina and a high yttria content has been developed for dental applications. Commercially available zirconia is commonly doped with 0.25 wt.% alumina [11]. For the fabrication of high-density zirconia, alumina is of particular importance as a contaminant because it improves the densification rate of zirconia; however, it reduces the transmission of visible light owing to the segregation of alumina on zirconia grain boundaries [12; 13]. In 2011, high translucent tetragonal zirconia polycrystalline (TZP) stabilized with 3 mol% of yttria containing less than 0.05 wt.% alumina was introduced into dentistry. Although reducing the amount of alumina to less than 0.05% can contribute to increasing translucency, it degrades the mechanical properties [14]. Dental prostheses not only restore functionality such as occlusal support and protection but also require esthetics to meet patient expectations. The high transparency of zirconia is particularly crucial for achieving natural esthetics in prosthetic restoration. For additive manufacturing, several processes have been developed, including binder jetting, material extrusion, powder bed fusion, and polymerization processes such as stereolithography (SLA) and digital light processing (DLP) [15]. Each method has its advantages and disadvantages [16]. Several additive manufacturing systems are commercially available for the production of dental restorations [17; 18]. The zirconia ceramic slurry composition used in the additive manufacturing process influences the overall quality of the final restorations. The ceramic grain sizes in zirconia objects fabricated using commercial additive manufacturing systems negatively impact the mechanical properties and density. As a result,zirconia ceramic restorations fabricated via additive manufacturing have fewer desirable properties than those fabricated via subtractive manufacturing. The most commonly used processes for 3D modeling ceramics are SLA and DLP [19; 20]. The systems based on these processes involve the creation of layers in either bottom-up or top-down approaches. In the bottom-up approach, the build platform begins at the bottom of the resin container and moves upward as each layer is cured. A light source, such as a projector for DLP or laser for SLA, cures the resin through a transparent window at the bottom of the container. In the top-down approach, the build platform begins at the top of the resin container and moves downward as each layer is cured. A light source cures the resin layer-by-layer from the top. While both bottom-up and top-down approaches have their advantages and limitations, the top-down approach is preferred in contexts where speed, efficiency, and reduced risk of print failures are critical factors [21]. The top-down approach has comparatively faster printing times because the object is continuously pulled out of the resin rather than being built layer-by-layer from the bottom. In the top-down approach, the object being built is not subjected to the peeling forces that the bottom-up approach involves while building each layer, and the risk of printing failures, such as detachment from the build platform, is reduced. In this study, we explored a commercial top-down SLA-based system for the additive manufacturing of ceramic prosthetic restorations. This SLA-based system can use formulated resin-ceramic slurries for the fabrication of ceramics. Relatively viscous slurries can be spread thinly with blades; however, if the viscosity is too high, it becomes difficult to uniformly spread the slurries. After the slurry is spread, it is photopolymerized. However, if the polymerization shrinkage is large, it causes deformation of the polymerized area, making layer formation difficult. Therefore, both the slurry and modeling conditions require optimization. We used 0.05 wt.% alumina and 3 mol% yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) because these values have been found to be suitable for fabricating dental crowns [22].