The Influence of Microstructure on the Flexural Properties of 3D Printed Zirconia Part via Digital Light Processing Technology

Abstract

In recent years, additive manufacturing of ceramics is becoming of increasing interest due to the possibility of the fabrication of complex shaped parts. However, the fabrication of a fully dense bulk ceramic part without cracks and defects is still challenging. In the presented work, the digital light processing method was introduced for fabricating zirconia parts. The flexural properties of the printed zirconia were systematically investigated via a three-point bending test with the digital image correlation method, scanning electron microscopy observation and fractography analysis. Due to the anisotropy of the sample, the bending deformation behaviors of the zirconia samples in the parallel and vertical printing directions were significantly different. The flexural strength and the related elastic modulus of the samples under vertical loading were higher than that of the parallel loading, as the in-plane strength is higher than that of the interlayer strength. The maximum horizontal strain always appeared at the bottom center before the failure for the parallel loading case; while the maximum horizontal strain for the vertical loading moved upward from the bottom center to the top center. There was a clear dividing line between the minimum perpendicular strain and the maximum perpendicular strain of the samples under parallel loading; however, under vertical loading, the perpendicular strain declined from the bottom to the top along the crack path. The surrounding dense part of the sintered sample (a few hundred microns) was mainly composed of large and straight cracks between printing layers, whereas the interior contained numerous small winding cracks. The intense cracks inside the sample led to a low flexural property compared to other well-prepared zirconia samples, which the inadequate additive formulations would be the main reason for the generation of cracks. A better understanding of the additive formulation (particularly the dispersant) and the debinding-sintering process are necessary for future improvement.

Innovation and Evaluations of 3D Printing Resins Modified with Zirconia Nanoparticles and Silver Nanoparticle-Immobilized Halloysite Nanotubes for Dental Restoration

“…This increase is observed when adding zirconia nanoparticles at concentrations of 4% and 8%, as well as HNC/Ag fillers at concentrations of 5%. These findings were reported earlier in [35][36][37].…”

Stress Distribution Pattern in Zygomatic Implants Supporting Different Superstructure Materials

“…The material’s constants (elastic modulus and Poisson ratio) were assigned to each volumetric element with isotropic and homogeneous consistency, based on data in the literature. The properties have been summarized in Table 1 [ 15 , 21 , 25 , 26 , 27 , 28 ]. Five different superstructures have been simulated, as showed in Figure 3 .…”

“…With the application of CAD/CAM, there are several superstructure materials that are suggested for implant-supported, full-arch rehabilitations, such as a cobalt–chrome alloy [ 2 ], a titanium alloy [ 7 ], zirconia [ 15 , 16 ], carbon-fiber polymers [ 17 , 18 ] and the polyaryletherketone family [ 14 , 19 ]. Despite the extensive literature on the effects of superstructure materials for conventional implants [ 6 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ], the data regarding biomechanical behavior of zygomatic implants are limited [ 2 , 6 , 21 , 22 ].…”

Surface Characteristics and Flexural Strength of Porous‐Surface Designed Zirconia Manufactured via Stereolithography

“…Dental restorations require adequate flexural strength to ensure they are permissible for clinical use and have enough durability under occlusal forces. The flexural strength of SLA‐fabricated zirconia ceramics is closely related to the ceramic suspension, processing parameters, phase transformation, density, and internal and surface defects 9,26–28 . The effects of the porous design on the mechanical properties of zirconia components remain unclear.…”

“…The flexural strength of SLA-fabricated zirconia ceramics is closely related to the ceramic suspension, processing parameters, phase transformation, density, and internal and surface defects. 9,[26][27][28] The effects of the porous design on the mechanical properties of zirconia components remain unclear.…”